Epidemiology and phenomenology of obsessive-compulsive disorder in non-referred young adolescents: a Polish perspective

Evaluating the diagnostic validity of CBCL-OCS in Chinese children and adolescents with OCD

BACKGROUND AND OBJECTIVES

Obsessive-compulsive disorder (OCD) is recognized globally as a serious mental health concern among children and adolescents. Accurate early diagnosis and intervention are crucial for effective management and improving patient outcomes. The primary objective of this study was to evaluate the diagnostic validity of the Child Behavior Checklist-Obsessive Compulsive Scale (CBCL-OCS) in Chinese children and adolescents, ensuring its cultural adaptability. The secondary objective was to explore the clinical characteristics of OCD, including prevalence, symptom severity, and comorbidities.

METHODS

A cross-sectional epidemiological survey was conducted among 8,595 middle school students in Liaoning Province, China. The CBCL-OCS was employed as the primary screening tool. The optimal cutoff value for OCD screening was determined through receiver operating characteristic (ROC) curve analysis.

RESULTS

The study found an OCD prevalence of 1.710%, which was consistent with the global estimation. ROC analysis determined a cutoff score of 2.5 for CBCL-OCS, with a sensitivity of 0.789 and a specificity of 0.899. Furthermore, adolescents exhibited significantly higher CBCL-OCS scores compared to younger children, suggesting an increase in OCD severity with age. Significant associations were also found between OCD symptoms and comorbid emotional disorders, behavioral problems, and anxiety symptoms.

CONCLUSIONS

This study confirms the utility of CBCL-OCS as an effective early screening tool for OCD in Chinese middle school students, highlighting its sensitivity and specificity, and cultural adaptability. Results contributed valuable insights to the epidemiology of OCD among children and adolescents, underscoring the need for targeted interventions during critical developmental periods, especially in adolescence.

The Prevalence and Comorbidity of Tic Disorders and Obsessive-Compulsive Disorder in Chinese School Students Aged 6-16: A National Survey

Background: Obsessive-compulsive disorder (OCD) and tic disorders (TDs) are closely related and considered to etiologically overlap. Both disorders are characterized by repetitive behaviors. TD and OCD often co-occur. The high comorbidity between OCD and TD individuals suggests that we also need to pay more attention to the homogeneity and heterogeneity between TS and OCD. To date, there has been no systematic nationwide epidemiological survey of the mental health (including tic disorders and obsessive-compulsive disorder) of children and adolescents in China. Methods: A two-stage epidemiological study of psychiatric point prevalence was conducted. We used the multistage cluster stratified random sampling strategy to assess five provinces of China. The Child Behavior Checklist was used to identify behavioral problems among the enrolled students in the first stage. The results from the Mini-International Neuropsychiatric Interview for Children and Adolescents and evaluations from two psychiatrists based on the Diagnostic and Statistical Manual-IV were used to make a diagnosis. Point weighted prevalence for TD and OCD was estimated. We adjusted prevalence estimates with the product of sampling weights and poststratification weights. Standard error values and 95% confidential intervals were generated with Taylor series linearization. Rao−Scott adjusted chi-square (χ2) tests were employed to compare the prevalence estimates of different age and sex groups. Results: In the first stage, 73,992 participants aged 6−16 years old were selected. The prevalence rates of OCD and TDs were 1.37% (95% CI: 1.28−1.45) and 2.46% (95% CI: 2.35−2.57), respectively. The prevalence of OCD was found to be higher in girls (p < 0.001) and higher in boys with transient tic disorder (TTD) (p < 0.001) and Tourette’s syndrome (TS) (p < 0.001). The most common comorbidity of TS was OCD (40.73%), and for OCD, it was TS (11.36%). Conclusions: Our study is the first nationwide survey on the prevalence of TD (2.46%) and OCD (1.37%) in school students aged 6−16 years old in China. The high comorbidity between OCD and TD individuals suggested overlap based on the prevalence dimensions, which might be influenced by age and sex. This result suggested that we also need to pay more attention to the homogeneity and heterogeneity between TS and OCD.

The role of early-life family composition and parental socio-economic status as risk factors for obsessive-compulsive disorder in a Danish national cohort

Research on early-life family environment on obsessive-compulsive disorder (OCD) risk is limited, and sex differences have not been sufficiently studied. We investigated early-life family composition and parental socio-economic status (SES) as OCD risk factors while stratifying for sex in a sample of 1,154,067 individuals from the Danish population (7550 of whom had OCD). Data on early-life family composition (birth order, number of siblings, number of parents in household at proband age 6), parental SES at age 6 (parental income, occupation, and education level), history of parental psychiatric illness, and parental age at birth on OCD risk (i.e., an ICD-10 diagnosis of F42.x) were obtained from Danish population registers. Survival analyses using Cox regression were performed with age as the underlying time variable. Analyses were adjusted for calendar time, and differential effect by sex was tested for exposures. We found that birth order and advanced maternal age were risk factors for OCD in males, and being an only child was associated with increased OCD risk in both sexes. Early childhood SES variables including parental education, occupation, and income were associated with OCD risk, and these effects were more pronounced in females. Significant interaction effects for parental education/occupation and the presence of non-OCD psychiatric diagnoses in the proband also emerged. Our results suggest that early-life SES and family composition may be important risk factors for OCD, and heterogeneity in OCD cases in terms of psychiatric comorbidities, as well as sex differences should be carefully examined in relation to risk factors.

Phenomenology of obsessive-compulsive disorder in children and adolescents: Sample from a tertiary care center in Istanbul, Turkey

BACKGROUND

Obsessive-compulsive disorder (OCD) is a heterogeneous disease in many respects and exhibits this diversity in terms of phenomenology. It also displays several different characteristics in children compared to adults.

AIM

To describe the socio-demographic and phenomenological features of children with OCD and to investigate the impact of these features on response to pharmacotherapy.

METHODS

This retrospective study was carried out with 150 children and adolescents who had been diagnosed with OCD between 2014 and 2018. Data was collected by examining the files of the patients with diagnosis of OCD and similar disorders from the hospital database. Yale-Brown Obsessive-Compulsive Scale for Children was used for the assessment of obsession-compulsion subtypes. The Clinical Global Impression (CGI) scale was used to evaluate the severity of the disease (CGI-S) and global improvement (CGI-I). The predictors of treatment response were evaluated using linear regression analysis. The level of significance for all statistic tests was set as P < 0.05.

RESULTS

The sample was divided into prepubertal (44%) and adolescent (56%) age groups. The most prevalent obsessions were contamination and aggression obsessions, and the most frequent compulsions were washing and checking. While contamination was observed more commonly in the prepubertal age group, the religious obsession was seen more frequently in adolescents. Patients with aggression obsession presented a higher frequency of comorbid anxiety (P = 0.022) and mood (P = 0.047) disorder. CGI-I scores did not differ according to phenomenological subgroups (P > 0.05). A lower CGI-I score was linked to a lower CGI-S score (95% confidence interval 0.21-0.39, P < 0.001) and the prepubertal age of admission (95% confidence interval 0.03-0.87, P = 0.020).

CONCLUSION

The phenomenology of OCD shows differences depending on the age group and the comorbid psychiatric disorders. Earlier identification and treatment of OCD may help to prevent the impairment of the mental health of children and adolescents.

Developmental Trajectories of Pediatric Obsessive-Compulsive Symptoms

Children who experience obsessive-compulsive symptoms (OCS) may be at risk for developing Obsessive-Compulsive Disorder (OCD). The current study aimed to investigate developmental trajectories of OCS, as well as possible predictors, within a community-based sample of children. Children (N = 1147) from the longitudinal NICHD Study of Early Child Care and Youth Development (SECCYD) were assessed for OCS, via the Child Behavioral Checklist - Obsessive-Compulsive Scale (OCS-8), eight times between Pre-Kindergarten (54 months; Pre-K) and High School (15 years of age; HS.) Participants were recruited within the United States and included only maternal caregivers. Preliminary analyses indicated that approximately 3% of the sample was above the diagnostic cutoff score on the OCS-8 at the High School time-point. Latent growth models tested symptom trajectories. Findings demonstrated three groups of OCS trajectories. Most children fell within a low symptomatology group (the No Peak group) with low OCS across all time points. Two additional OCS trajectories were also demonstrated: Pre-K Peak (high to low OCS across time) and HS Peak (low to high OCS across time). Both higher attention problems and greater depression/anxiety symptoms at the Pre-K time point predicted children's membership in the Pre-K Peak or HS Peak groups compared to the No Peak group. Membership within the HS Peak group predicted a high likelihood of children's OCS being above previously established cutoff scores for an OCD diagnosis at age 15 years. Membership within either the Pre-K Peak or No Peak groups predicted a low likelihood. This study provides new evidence for the existence of different developmental trajectories for youth with OCS. From a clinical perspective, these results may have important implications when considering the identification and early intervention of childhood OCS and OCD within the community.

Obsessive Compulsive Inventory - Child Version (OCI-CV): Confirmatory factor analysis, reliability, validity and correlates among Nigerian adolescents

Background

Obsessive compulsive symptoms (OCS) have not been studied among Nigerian adolescents, despite studies in developed countries reporting that almost 90% of affected adolescents do not receive any treatment. The availability of a psychometrically valid and reliable instrument will serve as an initial step towards the diagnosis and subsequent treatment of Nigerian adolescent obsessive compulsive disorder (OCD).

Aims

The aim of this study was to examine the psychometric characteristics as well as correlates of the Obsessive Compulsive Inventory — Child Version (OCI-CV) in a non-clinical sample of Nigerian adolescents.

Methods

This was a cross-sectional study involving 1017 adolescents who completed the Obsessive Compulsive Inventory-Child Version (OCI-CV), the Hospital Anxiety and Depression Scale (HADS), General Health Questionnaire-12 (GHQ-12) and Rosenberg's Self-Esteem Scale (RSES). The model fit of the OCI-CV 6 factors was examined through confirmatory factor analysis. Reliability was determined by calculating the McDonald's Omega hierarchical (ωh) values while its concurrent validity was examined through correlational analyses.

Results

The overall internal consistency of the OCI-CV was 0.96. The indices of fitness obtained on subjecting the 21 items of the OCI-CV to CFA indicated modestly acceptable indices of fitness despite satisfactory item loading on the 6 subscales. Statistically significant correlations were observed between OCI-CV and the other study measures. OCS was reported by 37.8%.

Conclusion

The OCI-CV has exhibited satisfactory psychometric properties among Nigerian adolescents.

Epidemiology and comorbidity of obsessive-compulsive disorder in late adolescence: a cross-sectional study in senior high schools in Greece

OBJECTIVE

The aim of this study was to examine the epidemiology, comorbidity and use of health services of obsessive-compulsive disorder (OCD) and subclinical obsessive-compulsive symptoms in late adolescence.

METHODS

A total of 2427 adolescents attending senior high schools in Greece were selected for a detailed psychiatric interview using the revised clinical interview schedule (CIS-R). Use of alcohol, nicotine and cannabis, and several socio-demographic and socio-economic variables were also assessed.

RESULTS

The prevalence of OCD was 1.39% (95% confidence interval [CI]: 1.05-1.84) while that of subclinical obsessive-compulsive symptoms was 2.77% (2.22-3.45). There was a female preponderance for subclinical symptoms. Financial difficulties of the family was the only socio-demographic variable that was significantly associated with OCD but not with subclinical symptoms. The pattern of comorbidity was similar for both conditions but milder in the subclinical form. About one in three reported use of general health services and one in ten use of psychiatric services.

CONCLUSIONS

OCD and subclinical obsessive-compulsive symptoms were relatively common. Comorbidity with other psychiatric disorders and use of substances was considerable even in subclinical status, but use of specialised health services was small. Clinical and research implications are discussed.

The Child Behavior Checklist-Obsessive-Compulsive Subscale Detects Severe Psychopathology and Behavioral Problems Among School-Aged Children

OBJECTIVE

The aims of this study were (1) to assess obsessive-compulsive symptoms (OCS) dimensionally in a school-aged community sample and to correlate them with clinical and demographical variables; (2) to determine a subgroup with significant OCS ("at-risk for OCD") using the Child Behavior Checklist (CBCL-OCS) and (3) to compare it with the rest of the sample; (4) To review the CBCL-OCS subscale properties as a screening tool for pediatric OCD.

METHODS

Data from the Brazilian High Risk Cohort were analyzed. The presence and severity of OCS were assessed through the CBCL-OCS subscale. DSM-IV psychiatric diagnoses were obtained by the Developmental and Well-Being Assessment. Behavioral problems were assessed using the Strengths and Difficulties Questionnaire, the Youth Strengths Inventory, and the CBCL internalizing and externalizing behavior subscales.

RESULTS

A total of 2512 (mean age: 8.86 ± 1.84 years; 55.0% male) children were included. Moderate correlations were found between OCS severity and functional impairment (r = 0.36, p < 0.001). Children with higher levels of OCS had higher rates of psychiatric comorbidity and behavioral problems (p < 0.001). A score of 5 or higher in the CBCL-OCS scale determined an "at-risk for OCD" subgroup, comprising 9.7% of the sample (n = 244), with behavioral patterns and psychiatric comorbidities (e.g., tics [odds ratios, OR = 6.41, p < 0.001]), anxiety disorders grouped [OR = 3.68, p < 0.001] and depressive disorders [OR = 3.0, p < 0.001] very similar to those described in OCD. Sensitivity, specificity, positive predictive value, and negative predictive value of the CBCL-OCS for OCD diagnosis were, respectively, 48%, 91.5%; 15.1%, and 98.2%.

CONCLUSIONS

The dimensional approach suggests that the presence of OCS in children is associated with higher rates of comorbidity, behavioral problems, and impairment. The "at-risk for OCD" group defined by the CBCL revealed a group of patients phenotypically similar to full blown OCD.

Clinical significance of psychiatric comorbidity in children and adolescents with obsessive-compulsive disorder: subtyping a complex disorder

A promising approach in relation to reducing phenotypic heterogeneity involves the identification of homogeneous subtypes of OCD based on age of onset, gender, clinical course and comorbidity. This study aims to assess the sociodemographic characteristics and clinical features of OCD patients in relation to gender and the presence or absence of another comorbid disorder. The sample comprised 112 children and adolescents of both sexes and aged 8-18 years, all of whom had a diagnosis of OCD. Overall, 67 % of OCD patients had one comorbid diagnosis, 20.5 % had two such diagnoses and 2.6 % had three comorbid diagnoses. The group of OCD patients with a comorbid neurodevelopmental disorder had significantly more family history of OCD in parents (p = .049), as compared with the no comorbidity group and the group with a comorbid internalizing disorder, and they also showed a greater predominance of males (p = .013) than did the group with a comorbid internalizing disorder. The group of OCD patients with internalizing comorbidity had a later age of onset of OCD (p = .001) compared with both the other groups. Although the initial severity was similar in all three groups, the need for pharmacological treatment and for hospitalization due to OCD symptomatology was greater in the groups with a comorbid neurodevelopmental disorder (p = .038 and p = .009, respectively) and a comorbid internalizing disorder (p = .008 and p = .004, respectively) than in the group without comorbidity. Our findings suggest that two subtypes of OCD can be defined on the basis of the comorbid pathology presented. The identification of different subtypes according to comorbidity is potentially useful in terms of understanding clinical variations, as well as in relation to treatment management and the use of therapeutic resources.

The Toronto Obsessive-Compulsive Scale: Psychometrics of a Dimensional Measure of Obsessive-Compulsive Traits

OBJECTIVE

To describe the Toronto Obsessive-Compulsive Scale (TOCS), a novel 21-item parent- or self-report questionnaire that covers wide variation in obsessive-compulsive (OC) traits, and to evaluate its psychometric properties in a community-based pediatric sample.

METHOD

The TOCS was completed for 16,718 children and adolescents between the ages of 6 and 17 years in a community setting. Internal consistency, convergent validity with the Obsessive-Compulsive Scale of the Child Behaviour Checklist (CBCL-OCS), divergent validity with the Strengths and Weaknesses of ADHD (Attention-Deficit/Hyperactivity Disorder) Symptoms and Normal Behaviour Rating Scale (SWAN), interrater reliability, as well as sensitivity and specificity of the TOCS were assessed.

RESULTS

The internal consistency of the 21 TOCS items was excellent (Cronbach's α = 0.94). TOCS was moderately correlated with the CBCL-OCS (Spearman correlation = 0.51) and poorly correlated with the SWAN (Pearson correlation = 0.02). Sensitivity and specificity analyses indicated that a TOCS total score of greater than 0 successfully discriminated community-reported obsessive-compulsive disorder (OCD) cases from noncases. OC traits were continuously distributed both at the total score and dimensional level in our pediatric community sample.

CONCLUSION

TOCS is a multidimensional measure of OC traits in children and adolescents with sound psychometric properties. TOCS reveals that OC traits are common and continuously distributed in a community sample. TOCS may be a useful measure for studies of the characteristics and etiology of OC traits.

An epidemological study of obsessive compulsive disorder in adolescents from India

OBJECTIVES

There is scarce data on the prevalence of OCD among adolescents in India. This study reports point prevalence of OCD among school students (age 12-18years) in the Kerala state of India and examines its association with ADHD, psychological distress, tobacco/alcohol abuse, suicide risk and history of sexual abuse.

METHOD

7560 students of 73 schools were self-administered the OCD subsection of Clinical Interview Schedule-Revised, the Composite International Diagnostic Interview (CIDI) for obsessive compulsive symptoms and other relevant instruments to identify OCD and related clinical measures. A diagnosis of ICD-10 OCD was derived through the CIS-R algorithm which required duration of at least 2weeks and at least a thought/behavior to be resisted along with a cut-off score for severity and impairment.

RESULTS

In the sample, 50.3% were males with a mean age of 15.2years (range of 12-18years). The response rate was 97.3% (7380 valid responses). 0.8% (n=61) fulfilled criteria for OCD with a male predominance (1.1 vs. 0.5%, p=0.005). Prevalence was higher among Muslims and increased with age. Taboo thoughts (62.3%) and mental rituals (45.9%) were the commonest symptoms. Those with OCD had significantly higher suicidal thoughts (59 vs. 16.3%, p<0.01) suicide attempts (24.6 vs. 3.8%, p<0.01), ADHD (28 vs. 4%, p<0.001), sexual abuse (24.6 vs. 4.2%, p<0.01), and tobacco use (23 vs. 6.8%, p=0.01). They also reported greater psychological distress and poorer academic performance.

CONCLUSIONS

OCD is common among adolescents in India. Its associations with ADHD, sexual abuse, psychological distress, poorer academic performance and suicidal behavior are additional reasons for it to be recognized and treated early.

Correlates of comorbid depression, anxiety and helplessness with obsessive-compulsive disorder in Chinese adolescents

OBJECTIVES

Youth with obsessive-compulsive disorder (OCD) are at risk of experiencing comorbid psychiatric conditions, such as depression and anxiety. Studies of Chinese adolescents with OCD are limited. The aim of this study was to investigate the association of depression, anxiety, and helplessness with the occurrence of OCD in Chinese adolescents.

METHODS

This study consisted of two stages. The first stage used a cross-sectional design involving a stratified clustered non-clinical sample of 3174 secondary school students. A clinical interview procedure was then employed to diagnose OCD in students who had a Leyton 'yes' score of 15 or above. The second phase used a case-control study design to examine the relationship of OCD to depression, anxiety and helplessness in a matched sample of 288 adolescents with clinically diagnosed OCD and 246 students without OCD.

RESULTS

Helplessness, depression and anxiety scores were directly associated with the probability of OCD caseness. Canonical correlation analysis indicated that the OCD correlated significantly with depression, anxiety, and helplessness. Cluster analysis further indicated that the degree of the OCD is also associated with severity of depression and anxiety, and the level of helplessness.

CONCLUSION

These findings suggest that depression, anxiety and helplessness are important correlates of OCD in Chinese adolescents. Future studies using longitudinal and prospective designs are required to confirm these relationships as causal.

A prospective study of paediatric obsessive-compulsive symptomatology in a Spanish community sample

The obsessive-compulsive manifestations course was assessed with the Leyton obsessional inventory-child version survey (LOI-CV) in a 3-year prospective study, using a non-clinical sample. From an initial sample of 1,514 school-age children who underwent symptoms screening for obsessive-compulsive, anxiety and depression, 562 subjects (risk group/without risk group) were re-assessed in the 2nd phase and 242 subjects were monitored after 3 years. LOI-CV scores significantly decreased over time independently of age and gender. The prevalence, persistence and incidence for two levels of severity of obsessive–compulsive manifestations ranged between 4.8-30.4%, 9.3-28.4% and 1.1-14.4%, respectively. 34.6-64.5% of obsessive-compulsive symptomatology was predicted by anxiety, depressive and obsessive-compulsive symptoms. For the obsessiveness (less severe form of obsessive-compulsive manifestations), the depressive symptoms were not predictors. Gender and socioeconomic status were not related with obsessive-compulsive manifestations. These data support a substantial continuity of the obsessive-compulsive manifestations and the existence of different levels of severity within the obsessive-compulsive spectrum.

The epidemiology of obsessive--compulsive disorder in Spanish school children

We aimed to assess the prevalence (at three levels of severity) and other epidemiological data of OCD in a sample of 1,514 Spanish non-referred children. The estimated prevalence was 1.8% for OCD, 5.5% for subclinical OCD and 4.7% for OC symptomatology. We did not find significant differences between genders or academic grade regarding OC symptoms and OCD, but more subclinical prevalence was found in males than in females. Socio-demographic variables were not related to any level of OCD, but academic performance was significantly lower in clinical OCD. The co-morbidity between OCD and any psychiatric disorder was high (85%) and higher for emotional disorders than for behavioral disorders. The impairment was associated with comorbidity and was worse for OCD with comorbid emotional problems. The results suggest that OCD is not rare in school children and adolescents and that it has an impact on their personal functioning. We suggest the possibility of an early diagnosis and treatment.

Sex determines which section of the SLC6A4 gene is linked to obsessive-compulsive symptoms in normal Chinese college students

Previous case-control and family-based association studies have implicated the SLC6A4 gene in obsessive-compulsive disorder (OCD). Little research, however, has examined this gene's role in obsessive-compulsive symptoms (OCS) in community samples. The present study genotyped seven tag SNPs and two common functional tandem repeat polymorphisms (5-HTTLPR and STin2), which together cover the whole SLC6A4 gene, and investigated their associations with OCS in normal Chinese college students (N = 572). The results revealed a significant gender main effect and gender-specific genetic effects of the SLC6A4 gene on OCS. Males scored significantly higher on total OCS and its three dimensions than did females (ps < .01). The 5-HTTLPR in the promoter region showed a female-specific genetic effect, with the l/l and l/s genotypes linked to higher OCS scores than the s/s genotype (ps < .05). In contrast, a conserved haplotype polymorphism (rs1042173| rs4325622| rs3794808| rs140701| rs4583306| rs2020942) covering from intron 3 to the 3' UTR of the SLC6A4 gene showed male-specific genetic effects, with the CGAAGG/CGAAGG genotype associated with lower OCS scores than the other genotypes (ps < .05). These effects remained significant after controlling for OCS-related factors including participants' depressive and anxiety symptoms as well as stressful life events, and correction for multiple tests. These results are discussed in terms of their implications for our understanding of the sex-specific role of the different sections of the SLC6A4 gene in OCD.

Childhood trauma and obsessive-compulsive symptoms

Childhood trauma is known to predispose to a variety of psychiatric disorders, including mood, anxiety, eating, and personality disorders. However, the relationship between childhood trauma and obsessive-compulsive symptoms has not been well studied. This study examines the relationship between childhood trauma, personality facets, and obsessive-compulsive symptoms in 938 college students using the Childhood Trauma Questionnaire, the Leyton Obsessional Inventory, and the NEO Personality Inventory-Revised. Between 13 and 30% of subjects met criteria for childhood trauma, with emotional neglect the most commonly reported experience. There was a small but significant association between obsessive-compulsive symptoms and childhood trauma, specifically emotional abuse and physical neglect, all of which was accounted for by co-occurring anxiety symptoms. An independent association was also seen between emotional abuse, physical abuse, and high levels of obsessive-compulsive symptoms ("probable obsessive-compulsive disorder"), which remained significant in the context of co-occurring anxiety symptoms. A similar association was seen between obsessive-compulsive symptoms and conscientiousness, and between emotional neglect and sexual abuse and conscientiousness, suggesting that an indirect role for childhood trauma in the development of obsessive-compulsive symptoms may also exist.

Performance of the adolescent obsessive-compulsive scale in a community survey

Obsessive-compulsive behavior was studied in a cohort of N=570 subjects who had been assessed at three times between adolescence and young adulthood. Based on the Youth Self-Report (YSR) and the Young Adult Self-Report (YASR), the adolescent obsessive-compulsive scale (AOCS) was defined. At each of the three assessments, subjects scoring above the cut-off score of the 90th percentile of the AOCS were identified and compared to the rest of the sample serving as control group. The risk group was clearly more abnormal in both domains of internalizing and externalizing across time. Various psychiatric disorders in young adulthood were predicted by the AOCS. However, concomitant general psychopathology also contributed strongly to the prediction. Parent and youth agreement on group membership was rather low. Stability of group assignment across time was significantly increased. The AOCS is a promising instrument both for epidemiological and clinical studies. Its content and predictive validity deserves further studies.

Evidence for a heritable unidimensional symptom factor underlying obsessionality

The division of obsessive-compulsive symptoms (OCS) into specific factors is now widely accepted. However, the utility of these categories for genetic studies remains unclear, as studies examining their heritability have been inconsistent. Less attention has been paid to the possibility that clinically significant obsessionality is primarily determined by a "core" group of OCS that crosses the boundaries between symptom subgroups. The aim of this study is to determine whether such a core group exists, and to compare its heritability to that of the more traditionally derived symptom factors. We examined the properties and heritability of obsessive-compulsive symptoms in college students, medical students, and obsessive-compulsive disorder (OCD) families using the Leyton Obsessional Inventory. In each of the three samples, we identified a core group of symptoms that comprised a single unique construct and accounted for over 90% of the variation of the four more traditional symptom factors. This core construct was highly correlated with OCD in our families and had a heritability estimate of 0.19 when OCD was not included as a covariate and 0.49 when OCD was included as a covariate. In contrast, the four symptom factors were not heritable. There appears to be an underlying unidimensional component to obsessionality, both in non-clinical and clinical samples. This component, which is heritable, accounts for the majority of the variation of the more traditionally derived symptom factors in our sample, and is composed of OCS that are not specific to any of the symptom subgroups.

The analytical epidemiology of obsessive-compulsive disorder: risk factors and correlates

In this qualitative systematic review, we evaluate studies of the demographic, innate, and environmental risk factors and correlates associated with the development of Obsessive-Compulsive Disorder (OCD) in epidemiological samples. We found that a significant proportion of the studies indicate that late adolescence is a period of increased vulnerability for the development of OCD; that OCD affects predominantly female adults and male children and adolescents; that those who are unmarried or abusing drugs are more likely to present with OCD; that OCD is a familial and genetic disorder, particularly when one considers symptom dimensions instead of categorical diagnosis and when the disorder begins at an early age; and that individuals with OCD from the community, like those seen in clinical settings, may be especially prone to present psychiatric conditions such as mood and anxiety disorders. Although there are plenty of data on the correlates and risk factors of OCD in epidemiological samples, more research is needed on other potential risk factors, including obstetrical and pregnancy problems, pre-morbid neurocognitive functioning, and streptococcal infections, among others.

Anxiety symptoms and perceived performance in medical students

Medical students represent a highly educated population under significant pressures. During the transition to clinical settings in the third year, they may experience a loss of external control and may counter this with an increase in obsessionality and/or other anxiety symptoms. Our study examines the phenomenology of obsessive-compulsive and other anxiety symptoms in medical students at two U.S. medical schools and relates these symptoms to self-perception of performance. Subjects anonymously completed a battery of questionnaires regarding obsessive-compulsive symptoms, attentional problems, anxiety symptoms, depressive symptoms, and perceived performance in medical school. A factor analysis of obsessional symptoms showed four primary factors: checking/doubts, contamination, long time/detail, and unpleasant thoughts/worries. These four factors were similar to those found among college students and other nonclinical populations. Anxiety, attentional, and depressive symptoms were highest in the third-year medical students. In contrast, obsessional symptoms were highest in the first-year students and lower for subsequent years. Perceived performance was not significantly correlated with obsessionality, although lower perceived performance was associated with higher levels of anxiety and depressive symptoms. Students with lower perceived performance in medical school were significantly more likely to be female, depressed, or older. The progressive decrease in number of obsessional symptoms across years and the lack of correlation with perceived performance suggest that these symptoms may be developmentally appropriate, and perhaps adaptive. In contrast, other anxiety symptoms appear to be maladaptive responses to external stressors.