Journal of the International Neuropsychological Society (2013), 19, 1–14. Copyright E INS. Published by Cambridge University Press, 2013. doi:10.1017/S135561771200152X

1 Neurocognition in Psychometrically Defined College

2 Schizotypy Samples: We Are NOT Measuring the

3 ‘‘Right Stuff’’

4 Charlotte A. Chun, Kyle S. Minor, AND Alex S. Cohen 5 Department of , Louisiana State University, Baton Rouge, Louisiana

6 (RECEIVED November 11, 2011; FINAL REVISION October 4, 2012; ACCEPTED October 4, 2012)

7 Abstract

8 Although neurocognitive deficits are an integral characteristic of , there is inconclusive evidence as to 9 whether they manifest across the schizophrenia-spectrum. We conducted two studies and a meta-analysis comparing 10 neurocognitive functioning between psychometrically defined schizotypy and control groups recruited from a college 11 population. Study One compared groups on measures of specific and global neurocognition, and subjective and objective 12 quality of life. Study Two examined working and subjective cognitive complaints. Across both studies, the 13 schizotypy group showed notably decreased subjective (d 5 1.52) and objective (d 5 1.02) quality of life and greater 14 subjective cognitive complaints (d 5 1.88); however, neurocognition was normal across all measures (d’s , .35). Our 15 meta-analysis of 33 studies examining neurocognition in at-risk college students revealed between-group differences in 16 the negligible effect size range for most domains. The schizotypy group demonstrated deficits of a small effect size for 17 working memory and set-shifting abilities. Although at-risk individuals report relatively profound neurocognitive deficits 18 and impoverished quality of life, neurocognitive functioning assessed behaviorally is largely intact. Our data suggest that 19 traditionally defined neurocognitive deficits do not approximate the magnitude of subjective complaints associated with 20 psychometrically defined schizotypy. (JINS, 2013, 19, 1–14) 21 22 Keywords: Risk marker, , Quality of life, Meta-analysis, Functioning, Students

23 INTRODUCTION handful of studies have not observed significant impairments 39 between schizotypy and control groups (e.g., Cohen, Iglesias, 40 24 Neurocognitive impairment is an integral feature of schizo- & Minor, 2009). Gaining a clearer perspective on how neuro- 41 25 phrenia, remaining stable across episodic and remissive cognitive abilities are affected across the spectrum holds 42 26 periods (Saykin, Shtasel, Gur, & Kester, 1994). Neuro- important implications for schizophrenia, as they may reflect 43 27 cognitive deficits are also potentially important for under- critical schizophrenic endophenotypes (Gur et al., 2007) and 44 28 standing schizotypy, defined as the ‘‘latent personality allow for detection of pre-morbid features of the illness. 45 29 organization that harbors the liability for schizophrenia’’ Many schizotypy studies investigating neurocognition 46 30 (Lenzenweger, 2006; Meehl, 1962). Whereas a broad have used psychometric identification methods in college 47 31 range of cognitive abilities are impaired in schizophrenia samples (Gooding & Braun, 2004). The use of college 48 32 (Heinrichs & Zakzanis, 1998), many studies suggest that samples is conceptually advantageous because subjects 49 33 individuals with schizotypy also exhibit impairment, albeit are recruited around the peak age of schizophrenia onset 50 34 attenuated in severity, in specific areas such as working (Chapman, Chapman, Kwapil, Eckblad, & Zinser, 1994) 51 35 memory (Gooding, Kwapil, & Tallent, 1999), delayed recall and can be tested without confounding factors, such as 52 36 (Vollema & Postma, 2002), visual spatial (Lenzenweger & medication effects. Individuals recruited using psychometric- 53 37 Gold, 2000), (Gooding & Braun, 2004), and identification methods may be less symptomatic than indivi- 54 38 language (Poreh, Ross, & Whitman, 1995). However, a duals in the schizophrenia-spectrum identified using 55 other methods (e.g., biological identification, ultra high risk 56 interview) because they generally have sufficient social, 57 Correspondence and reprint requests to: Alex Cohen, Louisiana State University, Department of Psychology, 236 Audubon Hall, Baton Rouge, cognitive, and financial resources to participate in higher 58 LA 70803. E-mail: [email protected] education. Accordingly, examination of neurocognition in 59

1 2 C.A. Chun et al.

60 college samples provides a key test of whether neurocognitive of schizotypy (at the 95th percentile or above). An important 117 61 impairment persists in even high-functioning populations on feature of our sample is that it was heterogeneous with respect 118 62 the schizophrenia spectrum. Our primary goal was to investi- to schizotypal traits; including positive, negative, and dis- 119 63 gate the relationship between neurocognition and schizotypy organized traits. This improves upon many prior studies that 120 64 in psychometrically identified college samples: we expected to use only one schizotypal trait dimension when examining 121 65 find specific, but not global, neurocognitive deficits. schizotypy and neurocognitive functioning. The results from 122 66 It is also important to consider whether neurocognitive Study One were inconsistent with our predictions, so we con- 123 67 deficits in schizotypy are associated with real world out- ducted further follow-up studies. In Study Two, we expanded 124 68 comes. In patients with schizophrenia, neurocognitive our tests to include executive functioning and subjective neuro- 125 69 impairments are associated with lower quality of life (QOL; cognitive complaints. In Study Three, we conducted a meta- 126 70 Chaplin et al., 2006; Ritsner, 2007), higher unemployment analysis of 33 studies investigating neurocognitive abilities in 127 71 rates (Gold, Queern, Iannone, & Buchanan, 1999), poorer college students with psychometrically defined schizotypy. 128 72 social skills, and less time spent in the community (Green, 73 1996). Patients with schizophrenia exhibiting neurocognitive 74 impairments also represent increased costs to the public STUDY ONE: METHODS 129 75 sector due to health and social care expenses (Patel et al., 76 2006). While a handful of studies demonstrate that func- Participant Selection 130 77 tioning and quality of life are impaired in individuals with Participants for Studies One and Two were recruited from the 131 78 schizotypy (Cohen & Davis, 2009), few examine the rela- undergraduate population at a university in the Southeastern 132 79 tionship between neurocognition and functioning. One study Unites States. Students completed one of two measures of 133 80 has shown a significant relationship between neurocognitive schizotypal traits online during separate data collection points 134 81 problems and poor functioning in those with schizotypy (n 5 1775 and 1507, respectively) for either course credit or a 135 82 (Aguirre, Sergi, & Levy, 2008), especially in the social chance to win cash prizes. From these pools, we recruited 136 83 domain; however, others have failed to find a significant individuals exhibiting elevated schizotypal traits on at least 137 84 relationship between these variables (e.g., Cohen, Leung, one of three subscales. Informed by (a) Meehl’s (1962) 138 85 Saperstein, & Blanchard, 2006; Dinn, Harris, Aycicegi, theories of schizotypy, (b) taxometric studies suggesting a 139 86 Greene, & Andover, 2002). A secondary goal of this project 10% population incidence of schizotypy (Lenzenweger & 140 87 was to assess whether neurocognitive impairments are related Korfine, 1992), (c) findings that over half of individuals in the 141 88 to real world outcomes in a schizotypy group. top 10% of SPQ scorers met criteria for a schizophrenia- 142 89 The final purpose of this study was to compare subjective spectrum disorder (Raine, 1991), and (d) evidence that the top 143 90 cognitive complaints between schizotypy and control groups, 5% of schizotypy scorers were nearly eight times more likely 144 91 to determine the degree to which students at risk for schizo- to report a history of schizophrenia diagnosis and ten times 145 92 phrenia report experiencing cognitive difficulties. Quality of more likely to report psychiatric hospitalization than controls 146 93 life questionnaires evaluate functioning by quantifying the at or below the mean (Cohen & Najolia, 2011), we defined 147 94 outcome of poor cognitive skills but do not directly measure the schizotypy group by a percentile score at or above the 148 95 subjects’ own assessment of their neurocognition. This key 95th percentile using sex and ethnicity derived means from the 149 96 distinction may clarify the underlying relationship between larger database on positive, negative or disorganized scales. 150 97 cognitive deficits and daily functioning. Interestingly, two The use of a 95th versus 90th percentile reflects a conservative 151 98 studies have reported that those with schizotypy self-report cutoff score, reflecting an attempt to reduce false positives, and 152 99 greater trouble with daily executive function than controls. has been used in our published research (e.g., Cohen & Hong, 153 100 However, in neither study did the schizotypy group differ 2011). Control participants were recruited from a pool of 154 101 from controls in objective measures of executive performance individuals scoring below the 50th percentile on each of the 155 102 (Chan et al., 2011; Laws, Patel, & Tyson, 2008). This suggests three schizotypy subscales. The final sample consisted of 156 103 that subjective neurocognitive concerns are pronounced 167 individuals with schizotypy and 57 control participants 157 104 in schizotypy populations, and that these concerns are not (for further recruitment details, see Minor & Cohen, 2010). 158 105 commensurate with standard measures of neurocognitive Subjects were paid $30 for their participation. The Chapman 159 106 functioning. This is an important finding to substantiate, as it Infrequency Scale (Chapman & Chapman, 1983) was used to 160 107 may suggest that deficits in the college population are not identify grossly inconsistent profiles (.3 items endorsed). 161 108 meaningfully captured by standard neurocognitive instruments. Informed consent was obtained from each subject and research 162 109 It may also mean that the primary deficit is in the subjective procedures were approved by the Institutional Review Board. 163 110 domain—perhaps reflecting autobiographical beliefs or other 111 ‘‘higher order’’ cognitive processes. 112 To address our goals, we conducted three studies to Measures 164 113 assess whether collegiate schizotypy and control groups Schizotypal traits 165 114 show neurocognitive dysfunctions. In Study One, we mea- 115 sured neurocognition and quality of life in a sample of 167 Two versions of the Schizotypal Personality Questionnaire 166 116 psychometrically identified individuals with extreme levels (SPQ; Raine, 1991) were used to measure schizotypal traits. 167 Neurocognition in college schizotypy samples 3

168 The SPQ (PsycINFO citations as of 8/15/2011 5 389) and Functioning 223 169 SPQ-Brief (SPQ-B; Raine & Benishay, 1995) (PsycINFO Quality of life was assessed using a modified version of 224 170 citations as of 8/15/2011 5 90) reflect two of the most Lehman’s Quality of Life Interview (QOL-I; Lehman, 1995). 225 171 oft-used schizotypy questionnaires. The full SPQ (n 5 1775) Quality of life was measured in 33 items across a range of 226 172 and SPQ-B (n 5 1507) were used respectively for subjects seven objective (e.g., ‘‘How often do you talk to your family 227 173 during the first and second data collection points. The on the phone’’) and subjective (e.g., ‘‘How do you feel about 228 174 full SPQ consists of 74 items and has demonstrated high your family’’) domains (home, daily activities, family, social, 229 175 internal reliability, test–retest reliability, and convergent and financial, health, and legal concerns). For data reduction 230 176 discriminant validity. The SPQ is also significantly correlated purposes, the scales were summed to create total Objective 231 177 (Wuthric & Bates, 2006) with the commonly used and and Subjective QOL-I scores (see Cohen & Davis, 2009 for 232 178 longitudinally verified (Chapman et al., 1994) Chapman psychometric support). 233 179 Scales: Perceptual Aberration (r 5 .70; Chapman, Chapman, 180 & Raulin, 1978), Magical Ideation (r 5 .72; Eckblad & 181 Chapman; 1983) and Social Anhedonia (r 5 .48; Eckblad, Proposed analyses 234 182 Chapman, Chapman, & Mishlove, 1982). The SPQ-B consists Analyses were conducted in three parts. First, we compared 235 183 of 22 items taken from the SPQ and has a commonly used age, gender, and ethnicity between control and schizotypy 236 184 three-factor solution (Cognitive-Perceptual, Interpersonal, and groups to determine whether these variables should be 237 185 Disorganization). It has demonstrated adequate reliability and controlled for in further analysis. Second, we used t tests to 238 186 ´ validity in several studies (e.g., Fonseca-Pedrero, Paıno-Pin˜eiro, evaluate whether neurocognitive functioning and quality of 239 187 ´ ´ ´ Lemos-Giraldez, Villazon-Garcıa, & Mun˜iz, 2009). To address life differed between control and schizotypy groups. It was 240 188 concerns that the original dichotomous response format is our expectation that the schizotypy group would show sig- 241 189 insensitive to trait intensity (Peltier & Walsh, 1990), we adopted nificantly poorer functioning in each of the neurocognitive 242 190 a 5-point Likert type response scale used in recent SPQ research domains. Finally, we investigated whether Objective and 243 191 (Wuthric & Bates, 2005). Subjects’ response options ranged Subjective QOL were related to neurocognitive performance 244 192 from ‘‘Strongly Disagree’’ to ‘‘Neutral’’ to ‘‘Strongly Agree.’’ using correlations. We hypothesized that QOL would be 245 193 The Likert scale version of the SPQ has shown high con- significantly correlated with each neurocognitive domain. All 246 194 a5 vergence and improved internal reliability ( .95) compared variables were relatively normally distributed. An alpha level 247 195 to the forced-choice dichotomous response version (Wuthric & of .05 was used for all analyses in this study. 248 196 Bates, 2005). To address potential concerns that the SPQ and 197 SPQ-BR tap different populations, we recomputed all group 198 comparisons for each questionnaire separately. The results did STUDY ONE: RESULTS 249 199 not substantively change.

Demographic and Descriptive Factors 250 200 Neurocognitive functioning Demographic and descriptive variables are presented in 251 201 Neurocognitive abilities were assessed using the Repeatable Table 1. No significant differences in age, gender, or ethnicity 252 202 Battery for the Assessment of Neuropsychological Status were observed when the schizotypy and control groups were 253 203 (RBANS; Randolph, 1998), which consists of twelve subtests compared (p’s . .10). 254 204 assessing five neurocognitive domains. The RBANS is 205 appropriate for use in patients with schizophrenia-spectrum Neurocognitive Performance and Quality of Life: 255 206 disorders, and has been cited by over 146 studies. Evidence Schizotypy Versus Control Groups 256 207 suggests that the RBANS is sensitive to neurocognitive 208 impairments commonly observed in schizophrenia (Gold et al., Table 2 contains the means and standard deviations for neuro- 257 209 1999) and has been previously used in studies of college schi- cognitive performance and QOL. Overall neurocognitive 258 210 zotypy samples (Cohen et al., 2009). Although originally used performance did not significantly differ between schizotypy 259 211 to measure deficits in psychotic and elderly populations, the and control groups. In contrast to our hypotheses, there were 260 212 RBANS has since been used to detect more subtle differences in also no significant differences between groups in any of the 261 213 younger populations, showing sensitivity for high-functioning five neurocognitive domains. The schizotypy group showed 262 214 athletes: youth (Moser & Schatz, 2002) and college students significantly lower scores as compared to controls for both 263 215 (Killam, Cautin, & Cantucci, 2005), as well as adolescents subjective and objective quality of life. 264 216 along the spectrum of schizophrenia disorders (Holzer et al., 217 2007). The RBANS is relatively efficient to administer, sensi- Neurocognition and QOL: Within Schizotypy 265 218 tive, reliable (a50.84), correlated with other neurocognitive 219 batteries, such as the Wechsler Adult Intelligence Scale-III Subjective QOL was not significantly related to neuro- 266 220 (r 5 .77; Wechsler, 1997a) and -III cognitive performance on any specific domain (p’s . .10). 267 221 (r 5 .69; Wechsler, 1997b), and is related to real world As predicted, objective QOL was associated with better 268 222 variables, such as employment status (Gold et al., 1999). overall neurocognitive performance (r[166] 5 .16; p , .05). 269 4 C.A. Chun et al.

Table 1. Demographic and descriptive characteristics for subjects in Study 1 and Study 2

Study 1 Study 2

Controls M (SD) Schizotypy M (SD) Controls M (SD) Schizotypy M (SD) (N 5 26) (N 5 89) (N 5 32) (N 5 71) Age 19.74 (4.63) 19.21 (1.55) 19.82 (6.35) 19.17 (1.84) Sex ( % Female) 53.2 65.1 74.2 67.3 Ethnicity (% Caucasian) 82.3 84.0 83.9 85.7 SPQ Factor Scores Positive 252.92 (8.49) 3.85 (18.36) 213.59 (2.49) 3.30 (5.54) Negative 225.35 (5.28) 7.74 (9.00) 213.41 (2.05) 4.04 (6.51) Disorganization 229.31 (3.72) 0.43 (11.50) 211.00 (1.59) 4.73 (4.22)

270 Performance in language domains was also related to higher The general null findings of this study could be explained 296 271 Objective QOL ratings (r[166] 5 .17; p , .05); however, it by the fact that there were few measures of working memory, 297 272 should be noted that these correlations were in the small which has been proposed as one of the key domains affected 298 273 effect size range (Cohen, 1988). None of the other correlations in individuals with schizotypy (Gooding et al., 1999). 299 274 for these analyses were statistically significant. A follow-up study was, therefore, conducted comparing 300 working memory in psychometrically defined college 301 students. It is also worth noting how dramatically quality of 302 275 STUDY ONE: DISCUSSION life was affected in the schizotypy population in comparison 303 to how neurocognition was preserved. The measures of 304 276 Study one examined neurocognitive performance and quality quality of life used in this study tap a broad range of domains, 305 277 of life in individuals with schizotypal traits. Contrary to our but generally do not assess cognitive complaints, so it was 306 278 expectations, no significant differences were found between unclear the degree to which individuals with schizotypy 307 279 the schizotypy and control groups for neurocognitive vari- report that their neurocognition abilities are impaired. This 308 280 ables. This was not a power issue, as there were no group issue was also redressed in Study Two. 309 281 differences in neurocognitive performance that rose to a 282 medium level or better. In contrast, we did find, as supported 283 by the literature (Cohen & Davis, 2009), that schizotypy was STUDY TWO: METHODS 310 284 associated with a declination in both objective and subjective 285 quality of life on the order of a large effect size. This suggests Participant Selection 311 286 that individuals with schizotypy not only experienced sub- 287 jective dissatisfaction with their general quality of life, but A separate data collection was conducted that was 312 288 experienced objectively defined impoverishment in life quality methodologically similar to that in Study One. In total, 313 289 as well (at least recorded via self-report). In terms of the rela- 1665 students completed the Schizotypal Personality Ques- 314 290 tionship between neurocognition and quality of life, we found tionnaire – Brief Revised version (Cohen, Matthews, Najolia, 315 291 that global and language performance were sig- & Brown, 2010). Of these, 47 individuals were recruited 316 292 nificantly correlated with objective functioning, suggesting for the schizotypy group and 30 were recruited for the 317 293 that at least some facets of neurocognition are important for control group using the same procedures as in Study One. 318 294 daily functioning. Generally, these correlations were not as The Chapman Infrequency Scale (Chapman & Chapman, 319 295 robust as expected. 1983) was used to identify grossly inconsistent profiles 320

Table 2. Comparison between Schizotypy and control groups on RBANS and QOL-I scores

Controls M (SD) Schizotypy M (SD) td Total RBANS Index 96.2 (10.9) 96.6 (10.5) 20.22 2.04 Immediate Memory Scale Index 96.7 (11.3) 99.2 (12.3) 21.42 2.21 Visuopatial/Construct. Scale Index 94.0 (19.1) 95.0 (16.4) 20.39 2.06 Language Scale Index 95.2 (9.7) 94.7 (12.2) 0.28 .05 Attention Scale Index 105.2 (13.1) 102.4 (14.4) 1.35 .21 Delayed Memory Scale Index 96.9 (9.7) 97.7 (9.3) 20.54 2.08 Subjective QOL-I 42.6 (5.7) 33.2 (6.6) 9.65 1.52 Objective QOL-I 1.2 (4.2) 23.8 (5.5) 6.32 1.02 Neurocognition in college schizotypy samples 5

321 (endorsing .3 items were excluded). Subjects were paid $30 cognitive complaints. Previous studies have shown a 370 322 for their participation in this study. significant correlation between self-report of working mem- 371 ory deficits and objective working memory performance 372 in schizophrenia samples (Garlinghouse, Roth, Isquith, 373 323 Measures Flashman, & Saykin, 2010), although this relationship does 374 375 324 Schizotypal Traits not appear to be preserved in schizotypy groups (Chan et al., 2011; Laws et al., 2008). An alpha level of .05 was used for 376 325 The SPQ-Brief Revised (SPQ-BR; Cohen et al., 2010) was all analyses in this study. 377 326 used to measure schizotypal traits in this study. The SPQ-BR 327 is an empirically based revision of the SPQ that features 328 improved psychometric properties over the SPQ-B, such STUDY TWO: RESULTS 378 329 as greater internal consistency (a5.90), sensitivity, and 330 convergent validity with relation to quality of life function- Demographic and Descriptive Factors 379 331 ing. It is comprised of 32 items cohering into seven separate 332 sub-ordinate subscales and three super-ordinate factors. Demographic and descriptive variables are presented in 380 333 As in Study One and in other recent research (Cohen et al., Table 1. No significant differences in age, gender, or ethnicity 381 334 2010), a Likert scale response format was used here (see were observed when the schizotypy and control groups were 382 335 Cohen et al., 2010; Wuthric & Bates, 2005 for reliability and compared (p’s . .10). 383 336 validity support).

Working Memory Performance: Schizotypy 384 337 Working memory tests Versus Control 385

338 We used five separate tests of working memory. These No significant differences were observed on working memory 386 339 included measures of verbal working memory: the digit span measures when the schizotypy and control groups were 387 340 forward, digit span backward, letter number, Continuous compared (see Table 3). 388 341 Performance Test – Individual Pairs; and of visual spatial 342 working memory: spatial span (MATRICS, MCCB; Subjective Cognitive Complaints: Schizotypy 389 343 Nuechterlein et al., 2008; Kern et al., 2008). Note that these 344 tests were selected based on their importance in schizo- Versus Control 390 345 phrenia more generally, as evidence of their inclusion in the The schizotypy group reported significantly greater sub- 391 346 MATRICS battery. jective cognitive complaints when compared to the control 392 group (see Table 3). 393 347 Subjective cognitive complaints

348 Subjective cognitive complaints were measured using the Subjective and Objective Neurocognition 394 349 Cognitive Difficulties Scale (McNair & Kahn, 1984). This Correlations 395 350 measure includes 26 items assessing a broad range of Subjective neurocognitive ability was found to be related 396 351 subjective complaints regarding basic neurocognitive func- to Digit Span Forward (r[45] 52.29; p , .05). No other 397 352 tions and their effects on daily functioning (e.g., ‘‘I forget significant correlations were observed for either group 398 353 appointments, dates, or meetings’’, ‘‘I fail to recognize (p’s . .10). 399 354 people I know’’). A total score, reflecting increasing levels of 355 cognitive complaints, was used in this study. Table 3. Working memory performance compared between the 356 Proposed analyses control and schizotypy groups

357 Analyses were conducted in three parts. First, we compared Controls Schizotypy 358 age, gender and ethnicity between control and schizotypy 359 groups to determine whether these variables should be MSDMSDt d 360 controlled for in further analyses. Second, t tests were Digit Span Forward 9.85 1.83 9.36 2.29 .92 .24 361 conducted to compare raw scores of working memory Digit Span Backwards 8.60 1.47 8.76 1.59 .42 2.10 362 performance between the schizotypy and control groups. Letter Number 17.81 2.63 17.63 3.10 .25 .06 363 We hypothesized that the schizotypy group would be Spatial Span 18.44 2.83 18.12 3.03 .43 .11 364 significantly more impaired on each of these measures. Third, CPT 2 digits 3.77 0.55 3.85 0.44 .73 2.16 365 t tests were conducted to examine group differences in CPT 3 digits 3.18 0.74 3.42 0.63 1.52 2.35 366 subjective neurocognitive complaints, with the expectation CPT 4 digits 2.09 0.83 2.12 0.76 .17 2.04 367 that the schizotypy versus control groups would show Subjective Cognitive 368 significantly more complaints. Finally, we examined the Complaints 27.10 10.41 47.38 11.17 7.97 21.88 369 relationship between working memory ability and subjective 6 C.A. Chun et al.

400 STUDY TWO: DISCUSSION Personality Inventory-168 (Hathaway & McKinley, 1983). 452 Unfortunately, the variability in methods was sufficiently 453 401 Study Two built on the findings of the first study by diverse as to render moderation analysis impractical. 454 402 expanding the focus to working memory and subjective 403 cognitive complaints. Although individuals with schizotypy Categorizing Neuropsychological Tests 455 404 were shown to have dramatically more subjective neurocog- 405 nitive complaints than controls (on the order of nearly two Neuropsychological tests examining global or specific neuro- 456 406 standard deviations), no significant differences in working cognitive domains were examined. In total, we categorized 457 407 memory were observed. This is consistent with previous tests into 10 different neurocognitive dimensions (global 458 408 findings in the college population (Laws et al., 2008; Chan cognition, memory, fluency, processing speed, set shifting, 459 409 et al., 2011). Collectively, these data suggest that college visual spatial, language, attention, working memory, and 460 410 students with schizotypy do not show dysfunction in reasoning). Tests were also categorized by whether they 461 411 basic neurocognitive functions, in contrast to reports of were timed versus untimed and overt visual spatial versus 462 412 demonstrative neurocognitive deficits (Poreh et al., 1995). language, due to the previous schizotypy literature on reac- 463 413 To investigate the state of the literature on neurocognition tion time (Lenzenweger, 2001) and hemispheric asymmetry 464 414 in college students with schizotypy, we next conducted a (Cohen et al., 2009). Categorizations were made using a 465 415 systematic and comprehensive meta-analysis of published team-consensus approach based on information obtained 466 416 studies on this topic. from test-manuals, from prior meta-analyses of this kind 467 (Cohen et al., 2007). 468

417 STUDY THREE: METHODS Meta-analytic Procedure 469

418 Search Strategy We used MetaWin statistical package to conduct our analyses 470 (Rosenberg, Adams & Gurevitch, 2000). Effect size values 471 419 To identify studies assessing neurocognitive performance were independently computed for each neurocognitive 472 420 in college schizotypy samples, we conducted a search in domain for each study using the Hedges d statistic. If multiple 473 421 2009 using PsycINFO, Psychology and Behavioral Sciences measures for a single domain were reported from a single 474 422 Collection databases (for a complete list of search terms used, study, these effect sizes were averaged together. Cumulative 475 423 see Appendix B). Our inclusion criteria consisted of: (1) studies effect sizes were computed using a procedure that statistically 476 424 with a psychometrically defined schizotypy group recruited weighs individual effect sizes by their reciprocal variance 477 425 from a college population; (2) the study had to contain means scores. The rationale for this weighting procedure is that 478 426 and standard deviations, correlations or other test statistics the closer a sample’s effect size approximates that of the 479 427 sufficient to compute effect sizes; (3) the study had to be population, the smaller the variance of that effect size will be. 480 428 published in a peer-reviewed journal; and (4) the study had to 2 Q statistics, based on w distributions, were also reported 481 429 measure either global or specific neurocognitive domains here. The Q , a measure of the total heterogeneity of a 482 430 using tests that are standardized or have documented psy- total sample, was used to determine whether the variability of 483 431 chometric support in a peer reviewed journal. This search was individual effect size values within a group were greater than 484 432 updated in 2012 to include recent studies. Including studies that predicted by sampling error. A significant Q value 485 433 One and Two, 33 total studies were included in the meta- total suggests that there is significant heterogeneity in effect 486 434 analysis (see Appendix A for a complete reference list). sizes within a group. All meta-analyses reported here used 487 random effects models. The analyses were conducted in three 488 435 Categorizing Psychometric Schizotypy Methods steps. First, we computed aggregate effect sizes comparing 489 436 Individuals with schizotypy included in this meta-analysis schizotypy and control groups on neurocognitive tests. 490 437 were defined by a variety of methods, such as standard Second, we separated tests into categories (neurocognitive 491 438 deviation, median, or percentage of the sample, as well as by domain, timed vs. untimed, visual spatial vs. language) and 492 439 score on the psychometric test. There were also a variety computed effect sizes for both groups. Finally, we conducted 493 440 of measures used: fourteen studies used the Chapman Scales: moderation analyses. This involved comparing effect sizes in 494 441 Perceptual Aberration Scale (Chapman et al., 1978), Revised neurocognitive performance between studies defining schi- 495 442 Physical Anhedonia Scale (Chapman & Chapman, 1978), zotypy in terms of positive/cognitive-perceptual (K, number 496 443 Magical Ideation Scale (Eckblad & Chapman, 1983), of studies 5 20) and negative/interpersonal (K 5 14) traits. 497 444 Revised Social Anhedonia Scale (Eckblad et al., 1982); seven Positive effect size values indicate that the schizotypy group 498 445 studies used the SPQ (Raine, 1991), six studies used the performed better than the control group, whereas negative 499 446 SPQ-B (Raine & Benishay, 1995), two studies used the effect sizes reflect the opposite. 500 447 Oxford-Liverpool Inventory of Feelings and Experiences 448 (Mason, Claridge, & Jackson, 1995), one study used STUDY THREE: RESULTS 501 449 the Cognitive Slippage Scale (Miers & Raulin, 1987), two 450 studies used the Schizotypal Personality Scale (Claridge & The findings for the meta-analysis investigating neurocognitive 502 451 Broks, 1984), and one study used the Minnesota Multiphasic domains are summarized in Table 4. More detailed findings 503 Neurocognition in college schizotypy samples 7

Table 4. Meta-analysis of studies comparing college students with psychometrically-defined schizotypy to controls across various cognitive domains

Cognitive Domain: K Schizotypy N Control N d 95% CI Qtotal Global Cognition 11 1103 689 .07 2.17 to .03 37.08** Memory 12 599 493 .04 2.09 to .16 8.08 Fluency 9 478 324 .01 2.14 to .17 7.35 Processing Speed 8 354 288 2.01 2.21 to .19 4.00 Set-Shifting 14 787 689 2.22a 2.32 to 2.10 27.35* Visual-Spatial 6 320 231 .05 2.15 to .25 8.56 Language 4 270 160 2.03 2.35 to .29 3.05 Attention 9 724 467 .11 2.25 to .03 3.80 Working Memory 12 630 478 2.27a 2.42 to 2.12 17.61 Reasoning 14 744 642 2.17 2.29 to 2.05 14.38 TOTAL 33 1987 1471 2.09 2.13 to 2.05 26.82** Untimed 28 1331 1101 2.14 2.22 to 2.06 27.95 Timed 18 1099 808 2.04 2.14 to .04 9.74 TOTAL 32 1749 1368 2.10 2.16 to 2.04 2.55 Non-visual-Spatial 23 1407 1091 2.10 2.18 to 2.02 26.22 Visual-Spatial 17 1033 719 2.13 2.23 to 2.03 28.01* TOTAL 27 1523 1203 2.11 2.17 to 2.05 .20

K 5 Number of studies a 5 d . 0.20 * 5 Qtotal p , .05 ** 5 Qtotal p , .01

504 including individual studies and measures used can be found two domains, with the schizotypy group performing more 533 505 in Appendix C, as Table 5. No meaningful differences poorly for set shifting and working memory, which have both 534 506 (defined as an effect size value ,.20; Cohen, 1988) were been shown as fundamental correlates of executive func- 535 507 found between the schizotypy and control groups on mea- tioning (Miyake, Friedman, Emerson, Witzki, & Howerter, 536 508 sures of global cognition, memory, fluency, processing 2000). Potential working memory differences were found in 537 509 speed, visual spatial, language, attention, and reasoning. contrast to the results from Study Two, which may have been 538 510 Small effect sizes (d 5 0.20–0.49; Cohen, 1988) were found underpowered due to small sample sizes. This discrepancy 539 511 for set shifting and working memory, suggesting that the could also be due to different tasks used: we tested neither 540 512 schizotypy group performed more poorly than controls in oculomotor delay response tasks nor delayed match-to-sample 541 513 these areas. The Q-total values were statistically significant tasks, which were included in some studies in the meta- 542 514 for each of these domains. Negligible effect sizes were analysis. It is also important to note that we were unable to 543 515 observed for timed versus untimed tests and language versus examine differences between schizotypy scales (e.g., SPQ vs. 544 516 visual spatial abilities. O-LIFE). It could be the case that neurocognition impair- 545 517 When the meta-analyses were recomputed for studies ments manifest differently as a function of how schizotypy is 546 518 using positive and negative schizotypy scales, the results did defined. This reflects a limitation that can be addressed 547 519 not appreciably change. For both studies using positive and in future studies. Nonetheless, these results do not provide 548 520 negative schizotypy scales, a small effect size deficit was evidence that at-risk individuals from a high-functioning, 549 521 observed in set-shifting and working memory abilities. university population exhibit global neurocognitive impair- 550 522 Positive schizotypy was also associated with a small effect ment. They also suggest that individuals from this population 551 523 size level difference in processing speed (K 5 3; d 52.24). exhibit negligible deficits in most specific neurocognitive 552 domains and, at best, modest executive functioning deficits. 553

524 STUDY THREE: DISCUSSION GENERAL DISCUSSION 554 525 In Study Three, we evaluated the findings from published 526 studies that compared neurocognitive functioning in schizo- The primary goal of this study was to assess whether 555 527 typy and control groups recruited from college populations. neurocognitive impairment is present in individuals with 556 528 Although many studies have reported significant findings psychometrically defined schizotypy recruited from college 557 529 (e.g., Gooding et al., 1999) we observed negligible effect populations. Focusing on the college population is important 558 530 sizes across most neurocognitive domains, independent of in discerning core characteristics of schizophrenia-spectrum 559 531 categorization. A total of 81% of studies examined showed only pathology from confounding post-psychotic factors. This 560 532 small or negligible findings. Small effect sizes were observed in examination reflects a key test of whether neurocognitive 561 8 C.A. Chun et al.

562 impairment remains stable even in high-functioning groups on deficits. In this regard, it seems relatively safe to conclude 619 563 the schizophrenia spectrum. There were three main findings that college-based studies using clinical neuropsychological 620 564 from these sets of studies. First, individuals with psychome- measures, at least as currently used, are not meaningfully 621 565 trically defined schizotypy showed marked concerns about tapping the ‘‘right stuff’’ (Green, Kern, Braff, & Mintz, 622 566 their neurocognitive functioning, and, consistent with a prior 2000). This observation has been made by others (e.g., Chang 623 567 report from our lab (Minor & Cohen, 2010), showed notable & Lenzenweger, 2004; Chan et al., 2011; Laws et al., 2008). 624 568 declines in both subjective and objective quality of life. Future research should focus on clarifying this striking dis- 625 569 In this regard, psychometrically defined schizotypy was parity. One possibility is that individuals with schizotypy are 626 570 by no means benign. Second, we did not observe any evi- impaired in some neurocognitive dimension not assessed 627 571 dence of global or overt neurocognitive deficits. Individuals using standard neurocognitive batteries. That is, memory 628 572 with schizotypy generally performed similar to controls. In and attention may largely be preserved, but other, as yet 629 573 the meta-analysis, schizotypy groups showed small reduc- unidentified cognitive abilities are impaired. Some possible 630 574 tions in executive functioning performance; however, as candidates that were not represented in our meta-analysis 631 575 with previous studies (Chan et al., 2011; Laws et al., 2008) include abstraction, cognitive control and social cognition. 632 576 performance was undemonstrative of their subjective com- Another possibility is that individuals with schizotypy show 633 577 plaints. Finally, neurocognitive functioning provided only very specific, focal neurocognitive deficits that are masked by 634 578 small contributions to the variance in quality of life in standard clinical instruments, which typically tap a broad 635 579 individuals with schizotypy. Thus, in contrast to patients range of neurocognitive, motivational and executive abilities. 636 580 with schizophrenia, individual differences in neurocognitive Perhaps the assessment of more specific cognitive abilities, 637 581 dysfunctions did not greatly explain subjective functional using techniques from cognitive sciences, may yield more 638 582 deficits. This study provides evidence that college students identifiable neurocognitive dysfunctions. Finally, it is possi- 639 583 with psychometrically defined schizotypy, as a group, do ble that individuals likely to endorse items on the SPQ are 640 584 not show pronounced neurocognitive deficits, at least, as also more likely to report personal problems on the QOL-I. 641 585 traditionally measured. This may reflect a response bias that could be avoided in 642 586 Working memory has been shown as a promising endo- future research by using more sensitive validity scales. It may 643 587 phenotype in schizophrenia pathology for individuals with also suggest that the deficit lies largely in the subjective 644 588 traceable genetic risk (Horan et al., 2008). Our meta-analysis domains, for example, reflecting biased autobiographical 645 589 found working memory and set-shifting abilities to be dis- beliefs or meta-cognitive processes. 646 590 turbed, at a small effect size level, in psychometrically In contrast to what is seen in schizophrenia (Ritsner, 2007) 647 591 defined college schizotypes. It stands to reason that this may the contribution of neurocognitive functioning to global 648 592 be a meaningful level of impairment for this high-functioning quality of life and functioning was relatively small. This 649 593 population; however, it is clear that the magnitude of suggests that the impoverishments in quality of life largely 650 594 impairment is not commensurate with subjective reports. It is reflect the impact of other factors than basic neurocognitive 651 595 worth noting that alternate recruitment methodologies not abilities, at least, other than those assessed using standard 652 596 included in this meta-analysis, such as biological identifica- clinical instruments. An important question becomes, what 653 597 tion (Asarnow et al., 2002) and ultra high-risk interview variables contribute to poor quality of life in the psychome- 654 598 (Trestman et al., 1995) consistently find significant neuro- trically defined schizotypy population? A recent study (Grant 655 599 cognitive impairment associated with these ‘‘at-risk’’ samples. & Beck, 2009) suggests an indirect relationship between 656 600 Thus, it stands to reason that neurocognitive deficits do neurocognitive deficits and impaired behavioral functioning 657 601 not manifest in all at-risk groups, such as high-functioning in individuals with schizophrenia, proposing that defeatist 658 602 college students, but may be present in those high-risk beliefs embody the important, underlying link between 659 603 individuals whose illness is most likely to worsen over time the two; this connection may be similarly represented in 660 604 (i.e., ultra-high risk patients). Heterogeneity, with regards non-psychotic, at risk individuals. Since those with schizo- 661 605 to schizotypy measures used and group definitions, could be typy from the college population exhibit problems in daily 662 606 considered a potential confound in this study. However, functioning, without proportional neurocognitive deficits, 663 607 sensitivity analyses generally failed to support this notion, as dysfunctional attitudes appear a likely candidate for the 664 608 there was little difference in magnitude of neurocognitive diminution in quality of life. Moreover, poor emotional 665 609 impairment between studies examining positive and negative intelligence in schizotypy leads to problems in social and 666 610 schizotypy. Nonetheless, we did not directly compare these family functioning (Aguirre et al., 2008). Therefore, the 667 611 studies, so heterogeneity of schizotypy remains an important subjective cognitive complaints and impoverished quality of 668 612 issue for future research. life found in our study could be due to defeatist cognitive 669 613 A key finding regards the seemingly profound discrepancy content or misguided personal and social beliefs. 670 614 in neurocognition between what individuals with schizotypy In summary, the present findings support the notion that 671 615 subjectively report and their actual abilities. Students at risk that psychometrically defined schizotypy is not benign, as 672 616 for schizophrenia showed a marked decline in QOL and even the college sample with schizotypy recruited in these 673 617 increased cognitive complaints, yet these problems did studies exhibited notable declines in quality-of-life and 674 618 not appear to be manifestations of classical neurocognitive increased concerns with their own neurocognitive abilities. 675 Neurocognition in college schizotypy samples 9

676 In answer to the question, is the field measuring the right Cohen, A.S., Matthews, R., Najolia, G., & Brown, L.A. (2010). 733 677 neurocognitive factors associated with psychometrically Psychometrically-sound brief measure of schizotypy: Improving 734 678 defined schizotypy in college samples, the response, based on the SPQ-B. Journal of Personality Disorders, 24, 516–537. 735 679 the present findings of large abnormalities in subjective but Cohen, A.S., & Najolia, G.M. (2011). Birth characteristics and 736 schizotypy: Evidence of a potential ‘‘Second Hit’’. Journal of 737 680 not objective functioning, is a relatively clear ‘‘no’’. Psychiatric Research, 45(7), 955–961. 738 Cohen, A.S., Saperstein, A.M., Gold, J.M., Kirkpatrick, B., 739 681 ACKNOWLEDGMENTS Carpenter, W.T. Jr., & Buchanan, R.W. (2007). 740 of the deficit syndrome: New data and meta-analysis of findings to 741 682 The authors acknowledge the efforts of Gina Najolia, Laura Brown, date. Schizophrenia Bulletin, 33(5), 1201–1212. 742 683 our undergraduate research assistants and our research subjects. The Cohen, J. (1988). Statistical power analysis for the behavioral 743 684 authors attest that they have no conflicts of interest. This work was sciences (2nd ed.). New Jersey: Lawrence Erlbaum Associates. 744 685 supported by an internal Louisiana State University grant and a Dinn, W.M., Harris, C.L., Aycicegi, A., Greene, P., & Andover, 745 686 Louisiana Board of Regents grant to the senior author. The funding M.S. (2002). Positive and negative schizotypy in a student 746 687 agency had no further role in study design; in the collection, sample: Neuro-cognitive and clinical correlates. Schizophrenia 747 688 analysis, and interpretation of data; in the writing of the report; and Research, 56, 171–185. 748 689 in the decision to submit the paper for publication. Eckblad, M.L., & Chapman, L.J. (1983). Magical ideation as an 749 indicator of schizotypy. 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Eckblad, M.L., Chapman, L.J., Chapman, J.P., & Mishlove, M. 1018 955 Lenzenweger, M.F., Cornblatt, B.A., & Putnick, M. (1991). 1982. The revised social anhedonia scale. Unpublished test. 1019 956 Schizotypy and sustained attention. Journal of Abnormal Hathaway, S.R., & McKinley, J.C. (1983). The Minnesota Multi 1020 957 Psychology, 100, 84–89. Phasic Personality Inventory (MMPI) manual. New York: 1021 958 Lenzenweger, M., & Gold, J. (2000). Auditory working memory Psychological Corporation. 1022 959 and verbal recall memory in schizotypy. Schizophrenia Research, Mason, O., Claridge, G., & Jackson, M. (1995). New scales for 1023 960 42(2), 101–110. the assessment of schizotypy. Personality and Individual 1024 961 Lenzenweger, M., & Korfine, L. (1994). Perceptual aberrations, Differences, 18, 7–13. 1025 962 schizotypy, and the Wisconsin Card Sorting Test. Schizophrenia Miers, T.C., & Raulin, M.L. (1987). Cognitive Slippage Scale. 1026 963 Bulletin, 20(2), 345–357. In K. Corcoran & J. Fischer (Eds.), Measures for clinical 1027 964 Martin, E.A., & Kerns, J.G. (2010). Social anhedonia associated practice: A sourcebook (pp. 125–127). New York: Free Press. 1028 965 with poor evaluative processing but not with poor cognitive Raine, A. (1991). The SPQ: A scale for the assessment of 1029 966 control. Psychiatry Research, 178, 419–424. schizotypal personality based on DSM-I-R criteria. Schizophrenia 1030 967 Park, S., Holzman, P., & Lenzenweger, M. (1995). Individual Bulletin, 17, 555–564. 1031 968 differences in spatial working memory in relation to schizotypy. Raine, A., & Benishay, D. (1995). The SPQ-B: a brief screening 1032 969 Journal of Abnormal Psychology, 104(2), 355–363. instrument for schizotypal personality disorder. Journal of 1033 970 Park, S., & McTigue, K. (1997). Working memory and the Personality Disorders, 9, 346–355. 1034 971 syndromes of schizotypal personality. Schizophrenia Research, 972 26(2), 213–220. 973 Peters, M., Smeets, T., Giesbrecht, T., Jelicic, M., & Merckelbach, APPENDIX B: META-ANALYSIS SEARCH 1035 974 H. (2007). Confusing action and imagination: Action source TERMS 1036 975 monitoring in individuals with schizotypic traits. Journal of 976 Nervous and Mental Disease, 195, 752–757. Schizot* 1 cognit* 1 college/undergrad*/ student* 1037 977 Poreh, A., Ross, T., & Whitman, R. (1995). Reexamination 978 of executive functions in psychosis-prone college students. Anhedon* 1 cognit* 1 college/undergrad*/ student* 1038 979 Personality and Individual Differences, 18(4), 535–539. Chapman 1 cognit* 1 college/undergrad*/ student* 1039 980 Spaulding, W., Garbin, C., & Dras, S. (1989). Cognitive 981 abnormalities in schizophrenic patients and schizotypal college Magical Ideation 1 cognit* 1 college/undergrad*/ student* 1040 12 C.A. Chun et al.

1041 Percept* Aberr* 1 cognit* 1 college/undergrad*/ student* Schizot* 1 languag* 1 college/undergrad*/ student* 1045

1042 Psychosis-prone* 1 cognit* 1 college/undergrad*/ student* Schizot* 1 verbal* 1 college/undergrad*/ student* 1046

1043 Schizot* 1 memor* 1 college/undergrad*/ student* Schizot* 1 spatial* 1 college/undergrad*/ student* 1047

1044 Schizot* 1 executive* 1 college/undergrad*/ student* Schizot* 1 attent* 1 college/undergrad*/ student* 1048 1049 APPENDIX C: DETAILED META-ANALYSIS TABLE

Table 5. Mean Effect Sizes Computed for Schizotypy vs. Controls

Untimed Total Total Schizotypy vs. N N Variance Study Measure Neurocognitive Test Timed Schizotypy Controls dd Global Cognition Burch 2006 A WASI-FSIQ: Vocab, Matrix Reasoning 0 37 38 2.45 .03 Chan 2011 B WAIS-R Estimate: Information, Arithmetic, X62632.24 .03 Similarity, Digit span Chun 2012, Study I C RBANS Total X 167 57 2.13 .04 Gooding 1999 D WAIS-R Estimate: Vocab, Block Design X 155 104 .14 .02 Gooding 2001 D WAIS-R Estimate: Vocab, Block Design X 125 83 2.03 .02 Gooding 2004 D WAIS-R Estimate: Vocab, Block Design X 50 45 .10 .04 Gooding 2006 D Shipley-Hartford Vocab, Abstraction X 256 137 2.01 .01 Suhr 1997 D WAIS-R Full Scale X 56 42 2.13 .04 Tallent 1999 D WAIS-R Estimate: Vocab, Block Design X 115 63 2.02 .02 Wang 2008 B WAIS-R Estimate X 41 20 21.68 .10 Woodward 2007 C NAART, Quick Test X 37 32 2.07 .02 Memory Aguirre 2008 C CVLT: Learning trials 1-5, Short & Long Delay 0 40 56 .08 .04 Recall Burch 2006 A Incidental Recall, Intentional Recall 0 37 38 .11 .03 Chan 2011 B WMS: Visual Reproduction Recall, Logical Memory 0 62 63 .36 .03 Chun 2012, Study I C RBANS Memory: Immed. & Delayed Recall for List 0 167 57 .09 .02 Learning, Story Memory, Figure Recall, Dinn 2002 C ROCFT Recall Accuracy 0 34 55 2.42 .05 Gooding 2004 D ROCFT: Delay Accuracy, Delay Line Bisection 0 50 45 2.03 .04 Jahshan 2007 C CVLT: Learning trials 1-5, Short & Long Delay 0 52 40 .19 .04 Recall Kim 2011 B K-CVLT: Learning trials 1-5, Short & Long Delay 0 28 31 .03 .07 Recall, Recognition Rate LaPorte 1994 D WMS-R: Immed. & Delayed Recall, Percent Retained 0 20 30 2.13 .08 Lenzenweger 2000 D Verbal Memory: Immed. & Delayed Recall 0 31 26 .07 .07 Wang 2008 B WMS: Visual Reproduction Recall, Logical Memory, 041202.34 .08 Prospective Memory Woodward 2007 C RAVLT Total 0 37 32 .12 .02 Fluency Chan 2011 B Category Fluency 1 62 63 2.03 .03 Chun 2012, Study I C RBANS: Category Fluency 1 167 57 .12 .02 Dinn 2002 C Letter Fluency 1 34 55 .01 .05 Duchene 1998 D Letter Fluency 1 20 20 .26 .10 Kim 2011 B COWA: Letter & Category Fluency 1 28 31 .19 .07 Laws 2008 C Letter & Category Fluency 1 29 32 .14 .07 Poreh 1995 E COWA 1 19 19 2.77 .11 Suhr 1997 D COWA 1 56 42 2.09 .04 Tsakanikos 2005 A Letter Fluency 1 61 0 2.02 .02

(Continued ) Neurocognition in college schizotypy samples 13

Table 5. Continued

Untimed Total Total Schizotypy vs. N N Variance Study Measure Neurocognitive Test Timed Schizotypy Controls dd Processing Speed Chun 2012, Study I C RBANS-Coding 1 167 57 .13 .02 Dinn 2002 C TMT-A 1 34 55 2.19 .05 Kim 2011 B TMT-A 1 28 31 .14 .07 Laws 2008 C BADS: Zoo Map Drawing Time 1 29 32 2.05 .07 Martin 2010 D Stroop Test Congruent RT 1 27 47 .08 .06 Park 1995 D WAIS-R Digit Symbol 1 28 23 2.36 .08 Poreh 1995 E TMT-A 1 19 19 .01 .11 Spaulding 1989 F COGLAB: RT 1 20 19 2.20 .10 Set Shifting Aguirre 2008 C WCST, Perseverative Errors 0 40 56 .07 .04 Bedwell 2006 C WCST, Total Errors 0 14 26 .46 .11 Chan 2011 B WCST, Perseverative Errors 0 62 63 2.12 .03 Dinn 2002 C TMT-B 1 34 55 2.13 .05 Gooding 1999 D WCST, Non-Perseverative Errors 0 155 104 2.44 .02 Gooding 2001 D WCST, Perseverative & Non-Perseverative Errors 0 125 83 2.34 .04 Jahshan 2007 C WCST, Perseverative Errors 0 52 40 .06 .04 Kim 2011 B WCST, Perseverative Errors, Total Errors 0 28 31 2.83 .07 Lenzenweger 1994 D WCST, Perseverative Errors 0 23 28 .00 .08 Martin 2009 D Stroop Test Incongr. RT 1 27 47 .02 .06 Poreh 1995 E TMT-B 1 19 19 21.01 .12 Tallent 1999 D WCST, Perseverative & Non-Perseverative Errors 0 115 63 2.46 .11 Suhr 1997 D WCST, Tower of Hanoi 0 56 42 2.37 .02 Woodward 2007 C WCST, Perseverative Errors 0 37 32 .03 .02 Visual Spatial Dinn 2002 C ROCFT: Copy Organization 0 34 55 2.17 .05 Chun 2012, Study I C RBANS- Figure Copy, Line Orientation 0 167 57 .18 .02 Gooding 2004 D ROCFT, WAIS-R Block Design 1 50 45 2.12 .04 Kim 2011 B ROCFT: Copy Accuracy & RT, Immed. 0 28 31 .06 .07 & Delayed RT Poreh 1995 E WAIS-R Block Design 1 19 19 2.27 .11 Spaulding 1989 F Mueller-Lyer, Size Estimation 0 20 19 2.30 .11 Language Chun 2012, Study I C RBANS- Picture Naming 0 167 57 .04 .02 Gooding 2004 D WAIS-R Vocab 0 50 45 .01 .04 Kerns 2008 G Peabody Picture Vocab 0 32 34 .00 .06 Poreh 1995 E WAIS-R Vocab 0 19 19 2.58 .11 Attention Bedwell 2006 C Span of Apprehension, CPT-IP: Omission Errors, 114262.13 .11 Commission Errors, False Alarms, RT Chan 2011 B SART: Correct, Commission Errors 0 62 63 .02 .03 Chun 2012, Study I C RBANS-Attention: Digit Span 0 167 57 .07 .02 Gooding 2006 D CPT-IP: Shapes & Numbers, Shapes & Numbers RT: 1 256 137 2.21 .01 Distraction: (RT, False Alarm, lnB, Hits, d’) Others: 0 Kim 2011 B D2: Total Errors, Concentration Performances 1 28 31 2.13 .07 Lenzenweger 1991 D CPT-IP: False Alarm, lnB, Hits, d’ 0 32 43 2.19 .06 Park 1995 D Oculomotor Delayed Response Task-Sensory: 0, 1 28 23 2.02 .08 % Correct, RT

(Continued ) 14 C.A. Chun et al.

Table 5. Continued

Untimed Total Total Schizotypy vs. N N Variance Study Measure Neurocognitive Test Timed Schizotypy Controls dd Spaulding 1989 F Apprehension/Masking, Vigilance False Alarms 0 20 19 2.32 .11 Tallent 1999 D Degraded Stimulus: % Correct, RT 0, 1 115 63 2.10 .02 Sensorimotor task: % Correct, RT 0, 1 Working Memory Chan 2011 B 2-Back: Accuracy 0 62 63 2.12 .05 LN-Span: Total Correct, Longest String Chun 2013, Study I C RBANS-Digit Span 0 167 57 2.40 .08 Chun 2013, Study II C Digit Span, LN-Span, CPT-IP, Spatial 0 47 30 2.24 .06 Gooding 2003 D Delayed Match-to-Sample: Identity, Emotion, 0, 1 43 39 2.26 .05 Spatial (% Correct, RT) Holzman 1995 D Oculomotor Delayed Response: % Correct 0 31 26 2.58 .08 Kerns 2008 G 3-Back WM Task: Accuracy Proportion 0 32 34 2.58 .06 Lenzenweger 2000 D LN-Span: Total Correct, Longest String 0 31 26 2.28 .07 Park 1995 D Oculomotor Delayed Response-Memory: 0, 1 28 23 2.12 .05 % Correct, RT Park 1997 B Spatial WM Task: % Correct 0 14 75 2.65 .09 Peters 2007 E Operation Span 0 17 17 2.13 .12 Tallent 1999 D Spatial WM: % Correct, RT 0, 1 115 63 2.40 .03 Wang 2008 B 2-Back: Total Correct, RT Correct 0, 1 41 20 2.75 .08 LN-Span: Total Correct, Longest Strings 0, 0 Reasoning Aguirre 2008 C WCST: Cards Sorted Correctly, Categories 0 40 56 .02 .04 Completed Bedwell 2006 C WCST: Trials to complete first set, Failure to 0 14 26 .20 .11 maintain set Chan 2011 B WCST: Categories Completed 0 62 63 2.12 .03 Dinn 2002 C Divergent Thinking, Porteus Maze 1 34 55 2.16 .05 Gooding 1999 D WCST: Categories Completed, Trials to first set, 0 155 104 2.20 .02 Failure to maintain set, Conceptual Level Gooding 2001 D WCST: Categories Completed, Trials to first set, 0 125 83 2.04 .04 Failure to maintain set, Conceptual Level Jahshan 2007 C TASIT: Parts 1–3 052402.02 .04 WCST: Categories Completed, Concept. Level Kim 2011 B WCST: Categories Completed 0 28 31 2.87 .07 Laws 2008 C Hayling Sentence Inhibition, Zoo Map 1 29 32 2.03 .07 Lenzenweger 1994 D WCST: Categories, Trials to first category, Failure to 023282.39 .08 maintain set, Learning to learn Park 1995 D WCST: Categories, Trials to first category, Failure to 028232.14 .08 maintain set, Learning to learn Poreh 1995 E Booklet Category Test: Errors 0 19 19 2.67 .11 Spaulding 1989 F Card Sorting 0 20 19 2.40 .10 Tallent 1999 D WCST: Categories Completed, Trials to first set, 0 115 63 2.19 .02 Failure to maintain set, Conceptual Level

A 5 O-LIFE, B 5 SPQ, C 5 SPQ-B, D 5 Chapman Scales, E 5 STA, F 5 MMPI, G 5 Cognitive Slippage Scale 0 5 Untimed, 1 5 Timed, *X 5 Both *(For studies employing both timed and untimed tests: if separate scores were given for each test, timed/untimed are reported separately. If only a composite score was given, timed/untimed is classified as X)