In this study, we determined the rates of current ICDs in 70 children and adolescents with life time DSM-IV OCD. To our knowledge, this is the largest and broadest sample of youth with primary OCD that has been studied and may increase the generalizability of the results. Only 17.1% of OCD subjects in this study had a current ICD, and the majority of subjects diagnosed with an ICD reported symptoms of either skin picking or nail biting.
The rates of ICDs found in this study are similar to the rates found in previous samples of adult OCD subjects (16.4% to 35.5%) (Fontenelle et al., 2005
; Matsunaga et al., 2005
; Grant et al., 2006
). Also like other studies in adults with OCD, the grooming disorders were well represented in youth with OCD. Although epidemiological studies of grooming disorders have not been performed, the rate of current skin picking (12.8%) was higher than reported in other populations (2% in dermatological patients [Griesemer, 1978
; Gupta et al., 1987
] to 2.7%–3.8% in college students) (Arnold et al., 2001
; Keuthen et al., 2000
). Nail biting was the second most common ICD found in this study (current rate of 10.0%), and this rate was also higher than the 6.4% current prevalence rate found in one study of college students (Teng et al., 2002
). Similarly, the rate of trichotillomania in this study (1.4% current) was similar to those found in the general population (1.0%–2.5%) (Christenson et al., 1991
; Rothbaum et al., 1993
). Therefore, this study suggests that the grooming disorders may be more common in youth with OCD than in the general population. One possible explanation for the fact that grooming disorders were common could be that these behaviors tend to reduce anxiety, much as compulsions do. Conversely, kleptomania, pyromania, and pathological gambling are more typically described as reward-driven or pleasurable. This elevated rate of co-occurrence of grooming disorder may support some shared underlying neurobiological correlates and genetic factors in at least some individuals with these ICDs (Bienvenu et al., 2000
). One previous study found significantly higher rates of these grooming disorders in first-degree relatives of OCD probands thereby demonstrating a possible familial transmission (Bienvenu et al., 2000
Of note was the fact that other ICDs appear to be quite rare in children and adolescents with OCD. Although epidemiological studies of most ICDs are lacking, recent studies estimate that the prevalence of problem gambling among adolescents ranges from 1% to 9% (Jacobs, 2004
). The current rate of pathological gambling in this sample of youth with OCD (0%) is therefore notably lower than found in the general population. In addition, the findings from this study of the current rates of kleptomania (1.4% compared to 8.8%) and pyromania (0% compared to 6.9%) were lower than rates found in a population of adolescent psychiatric inpatients (Grant et al., 2007
). These findings support previous studies that have found the co-occurrence of pathological gambling, kleptomania, or pyromania in samples of OCD subjects to be uncommon (Fontenelle et al., 2005
; Grant et al., 2006
). These findings may suggest that the concept of the obsessive compulsive spectrum is too broad and that only certain ICDs should be included.
OCD youth with a current ICD were more likely to have a co-occurring tic disorder. OCD with tic disorders may occur earlier in life than OCD without tics (Rosario-Campos et al., 2001
; Jaisoorya et al., 2008
). Because age of onset of OCD diagnosis was not significantly different between groups, age as a confounding variable seems less likely and the association of ICDs and tic disorders appears reinforced and independent of age. This finding is also consistent with a recent multi-level latent class analysis that found that OCD subjects with comorbid tic disorders were more likely to have grooming disorders (Nestadt et al., 2008
). Is there a common biology underlying both the grooming ICDs and tic disorders? Studies suggest that dopamine dysregulation may underlie tic disorders (Leckman et al., 1997
) and a similar hypothesis may explain grooming disorders (Hemmings et al., 2006
). Further studies are needed to examine to what extent tics and grooming ICDs share common neurobiology. These findings may also begin to explain why dopamine antagonists have shown some efficacy in the treatment of both tic disorders and grooming ICDs (Onofrj et al., 2000
; Arnold et al., 2001
; Dion et al., 2002
; Stewart and Nejtek, 2003
; Scahill et al., 2003
Our hypothesis that ICD presence would be positively associated with greater functional impairment or greater rates of psychiatric hospitalization was not supported by these data. These results seemingly contrast with findings in OCD adults in whom ICD co-occurrence was associated with more frequent psychiatric hospitalizations and functional difficulties (Grant et al., 2006
). The differences between adults and youth with OCD and ICDs may suggest that if left untreated, ICD presence in OCD may progress to a more severe form of OCD. Clinicians should carefully screen OCD patients for skin picking and nail biting, as the presence of these disorders may have treatment implications. Further research is needed to explore how the relationship between OCD and ICDs may affect treatment outcome. In addition, research is needed to clarify the extent to which each disorder may contribute to the other disorder’s development and maintenance.
This study has several limitations. Most notably, we based ICD diagnoses on subject report only and did not obtain information from parents. Because the behaviors associated with ICDs are often denied due to shame, the rates found in this study may underestimate the actual rates of ICDs in subjects with OCD. Also, we did not evaluate subjects for certain ICDs (e.g., compulsive internet use, compulsive videogame playing, compulsive buying) that might be more common in this age group. If we had, the rates of ICDs may have been arguably higher. Furthermore, this study is cross-sectional and not prospective. Therefore, a clear understanding of how the ICD and OCD are related is beyond the scope of this analysis. In addition, it is unclear how generalizable our results are to youth with OCD in the community. Because the subjects in this study were recruited from specialized services, they probably represent more severe cases compared to non-specialized services and the community. Also, although this study recruited from multiple treatment sites, only youth with primary OCD were enrolled in the study. Therefore, those individuals with a primary ICD and secondary OCD were not included, and this may have resulted in an under-estimation of ICD comorbidity. Nonetheless, our sample may generalize better than previous OCD studies, in that the study inclusion/exclusion criteria were very broad. The study also used both self-report and interviewer-administered measures with strong psychometric properties and established norms. Ideally, having a population-based control as part of this study and assessing the same ICDs with the same criteria, would strengthen these findings.
In conclusion, these results suggest that ICDs are relatively uncommon in youth with OCD. The notable exceptions appear to be skin picking and nail biting. Additional research on this topic is needed, including larger prevalence studies, studies of clinical correlates of ICDs in OCD, and studies that may shed light on the relationship between OCD and ICDs (e.g., studies assessing rates of OCD in ICD samples, prospective studies, and studies of etiology and pathophysiology). OCD is a highly heterogeneous disorder, and therefore future studies examining ICD co-occurrence in larger samples of youth with OCD are needed to determine whether certain OCD symptom dimensions are associated with differential treatment responses.