Acta Derm Venereol 2014; 94: 67–71 CLINICAL REPORT Onychophagia and Onychotillomania: Prevalence, Clinical Picture and Comorbidities Przemysław PACAN1, Magdalena GRZESIAK1, Adam REICH2, Monika Kantorska-JANIEC1 and Jacek C. Szepietowski2 1Department of Psychiatry, and 2Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Wroclaw, Poland Onychophagia is defined as chronic nail biting behaviour, younger than 3–6 years (8, 9). By the age of 18 years the which usually starts during childhood. Onychotilloma- frequency of this behaviour again decreases; however, nia results from recurrent picking and manicuring of the it may persist into adulthood in some subjects (8, 10). fingernails and/or toenails, leading to visual shortening According to the International Classification of Di- and/or estraction of nails. The aim of this study was to seases and Health Related Problems – 10th Revision assess the prevalence of onychophagia and onychotillo- (ICD-10), nail biting is classified as other specified mania in young adults, and the comorbidity of these con- behavioural and emotional disorders with onset usu- ditions with anxiety disorders and obsessive compulsive ally occurring in childhood and adolescence (F98.8), disorders (OCD), as well as to determine factors related together with excessive masturbation, nose picking, and to these behaviours. A total of 339 individuals were inter- thumb sucking (11). Diagnostic criteria have not been viewed with a structured questionnaire. Onychophagia well described for this group of disorders. was present in 46.9% of participants (including 19.2% Onychophagia seems to be a variant of compulsion, active and 27.7% past nail biters), and an additional 3 which may lead to destruction of the fingernails. Nail people (0.9%) had onychotillomania. The majority of biting is an under-recognized problem in daily clinical subjects (92.2%) described nail biting as an automatic practice, occurring as a continuum from mild to severe behaviour. Tension before nail biting was reported by (12, 13). Some studies indicate that nail biting may re- 65.7% of nail biters, and feelings of pleasure after nail sult from over-stimulation (due to stress or excitement) biting by 42%. Among the participants with lifetime ony- or under-stimulation (due to boredom or inactivity) chophagia, 22.5% met criteria of anxiety disorder and (12, 14). Nail biters often bite off rough, broken or 3.1% of OCD, while in the group without onychophagia sticking out fragments of the cuticles or fingernails in at least one anxiety disorder was diagnosed in 26.2% and order to make the fingernails smooth and appear perfect OCD in 5.0%. We did not find any correlation between or regular (14). In addition, some individuals seem to nail biting and other anxiety disorders or OCD. In con- experience pleasure and relaxation during nail biting clusion, no single condition was associated with nail bit- (14). Some observations suggested comorbidity of nail ing or influenced such behaviour; multiple psychological biting and OCD or anxiety disorders (15, 16). factors were involved. Key words: onychophagia; nail bit- Onychotillomania results from recurrent picking and ing; onychotillomania. manicuring of the fingernails and/or toenails, leading to visual shortening and/or estraction of the nails (17–19). Jacek C. Szepietowski, Department of Dermatology, Vene- There are no epidemiological data on this behaviour, reology and Allergology, Wroclaw Medical University, Ul. and our knowledge about onychotillomania is limited Chalubinskiego 1, PL-50-368 Wroclaw, Poland. E-mail: to a few case reports (18, 20–22). The aim of the pre- [email protected] sent study is to provide further data on the prevalence Accepted Feb 14, 2013; Epub ahead of print Jun 5, 2103 of onychophagia and onychotillomania among young adults, and to determine the comorbidity of anxiety di- Acta Derm Venereol 2014; 94: 67–71. sorders and OCD, and the factors related to nail biting behaviour. Onychophagia is defined as chronic nail biting behaviour, which usually starts during childhood or early adulthood MATERIALS AND METHODS (1–3). It is estimated that more than half of the school-age The study was approved by the ethics committee of Wro- population frequently, or at least occasionally, bites their claw Medical University. A total of 343 medicine students of fingernails (4). There are only a few published studies Wroclaw Medical University were initially recruited into the analysing the frequency of this problem in the general study. Four subjects (1.2%) declined to participate. Written population, most of which are limited to children and informed consent was obtained from all remaining participants: 208 (61.4%) females and 131 (38.6%) males, mean ± SD age adolescents. The prevalence of onychophagia found 23.9 ± 1.1 years, range 21–26 years, after providing full infor- among children and adolescents ranges from 20% to 29% mation about the study. As there is no diagnostic instrument to (5–7). Onychophagia has rarely been noted in children assess onychophagia, a specially designed questionnaire was © 2014 The Authors. doi: 10.2340/00015555-1616 Acta Derm Venereol 94 Journal Compilation © 2014 Acta Dermato-Venereologica. ISSN 0001-5555 68 P. Pacan et al. developed for the study. All included subjects completed the Table SI1. A significant portion of participants (n = 32; questionnaire, to determine the presence of onychophagia or 48.5%) reported nail biting several times a month. onychotillomania and characterize the nail biting behaviour. The questionnaire included questions on demographic data, date Only 6 persons (9.1%) bite fingernails every day. The of onychophagia and/or onychotillomania onset, localization, analysed subjects usually bit their fingernails less than frequency and intensity of nail biting, feelings accompanying 5 times a day (n = 59; 89.4%) and spent < 10 min/day the nail biting (e.g. pleasure/gratification/relief after nail biting, on nail biting (n = 47; 71.2%) (Table SI1). The mean tension before or when trying to resist nail biting), presence of duration of nail biting per day was 7.6 ± 7.7 min, ranging nail eating, whether nail biting was intentional or automatic, and whether it occurred or not during other activities. According to from 1 to 30 min. More than half of participants with the onset of nail biting, participants with onychophagia were active onychophagia (n = 39; 59.1%) tried to give up divided into 2 groups: early onset (before the age of 13 years), nail biting; the mean duration of periods of cessation and late onset of onychophagia (after the age of 13 years). The of nail biting was 3.8 ± 2.6 months, ranging from 0.5 to lifetime prevalence of anxiety disorders and OCD has been 12 months. No statistically significant differences were determined according to the ICD-10 (11). Each participant found between females and males regarding nail biting was examined by a psychiatrist (PP, MG or MK-J) using the 1 computerized Munich version of the Composite International characteristics (Table SI ). Diagnostic Interview (CIDI), a fully-structured diagnostic in- Specific factors related to nail biting are shown inTa - strument designed by the World Health Organization (WHO) ble SII1. Five persons (7.6%) always felt tension before for identifying mental disorders based on diagnostic criteria of nail biting or when trying to resist such behaviour, and the ICD-10 and Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) classifications (23). Several a further 36 individuals (58.1%) had this feeling at least studies confirmed the reliability and validity of the CIDI (e.g. sometimes. Feelings of pleasure, gratification or relief 24, 25), and it has been used in many epidemiological studies occurring at least sometimes after nail biting confirmed on the general population, as well as in studies evaluating the 24 participants (42%), while 32 persons (57.1%) never prevalence of mental disorders among patients with various had such feelings. The majority of participants (n = 59; medical conditions (e.g. 26, 27). All results were analysed using the software package Statis- 92.2%) described nail biting as an automatic behaviour, tica® 10.0 (Statsoft, Krakow, Poland). The significance of the without thinking about it. They usually bit their finger- observed differences between studied groups was determined by nails during other activities, such as watching television, the Student’s t-test, Pearson’s χ2 test, or two-sided Fisher’s exact using a computer, learning, reading, etc. Only 5 persons test. A p-value < 0.05 was considered statistically significant. (7.8%) never bit their fingernails automatically. In 20 participants (39.3%) nail biting was an intentional ac- tion; they interrupted other activities in order to carry RESULTS out nail biting. For most females (82.3%) nail biting was Clinical characteristics of onychophagia not an intentional activity, while most males (51.5%) acknowledged, that they had bitten their fingernails A total of 160 persons (47.2%) reported nail biting intentionally, interrupting other activities at the same during their lifetime, and an additional 3 persons (0.9%) time. The difference in the frequency of intentional reported problems of onychotillomania. Onychophagia nail biting between females and males was statistically was diagnosed in 95 females (59.4%) and 65 males significant (p = 0.02) (Table SII1). There was also a (40.6%) (p = 0.43). The mean age of onychophagia statistically significant difference between women and onset was 8.0 ± 3.5 years, age range 3–20 years. The men considering the frequency of automatic nail biting majority of individuals (86.2%) started nail biting (p = 0.02). No other relevant differences were observed before the age of 13 years, and only 22 participants regarding gender (Table SII1). (13.8%) reported later onset. The mean age of onset Groups with different onychophagia onset did not among females was 7.7 ± 3.5 years, and among males differ from each other in terms of continuing nail biting 8.1 ± 3.6 years (p = 0.47).