Neurocognition in Psychometrically Defined College Schizotypy Samples: We Are NOT Measuring the ''Right Stuff''

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 Psychology, 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 schizophrenia, 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 memory 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, Psychopathology, 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), attention (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

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