Obsessive–compulsive symptoms in sibling pairs concordant for obsessive–compulsive disorder

Abstract

Obsessive-compulsive disorder (OCD) is a heterogeneous disorder of unknown etiology. Phenotypic studies of affected sib-pairs (SPs) may help to characterize familial components of the phenotype. To determine whether SPs affected with OCD are similar in age at onset of obsessive-compulsive symptoms (OCS), symptom dimensions and presence of tic disorders (TDs). Forty OCD siblings ranging from 13 to 59 years old were evaluated by expert psychiatrists or psychologists. Families with two or more siblings affected with OCD were recruited from several OCD clinics in Brazil. The Yale Brown Obsessive-Compulsive Scale Checklist was used to assess OCS and the severity of OCD. The OCD diagnoses were made according to the DSM-IV. The chi-square test was used to assess concordance of TD presence within SPs based on the TD frequency reported in the literature (30%). There were significantly more siblings with early-onset OCS than with late-onset OCS (P = 0.002). Age at onset of OCS correlated positively and significantly between the two members of each SP (P = 0.005). Fourteen patients (35%) were diagnosed with TDs. There was no concordance of the TD presence within the SPs. When both were male, there was a significant sibling correlation in the contamination obsessions/cleaning compulsions dimension (ICC = 0.74; P = 0.002). Similarly, when both siblings were female, they were comparable in the hoarding obsessions/compulsions dimension (ICC = 0.76; P = 0.01). Familial factors seem to contribute to specific OCD phenotypic components such as age at onset of OCS and specific dimensions. The obvious influence of gender is as yet unexplained.

Sex-specific clinical correlates of hoarding in obsessive-compulsive disorder

“…It remains to be determined whether the clinical differences identified in this study reflect sex-specific differences in the course and expression of an underlying hoarding vulnerability, or in etiology and pathogenesis. Interestingly, the sib-sib correlation of hoarding dimension scores has been found to be stronger for hoarding than for other OCD symptom dimensions, and stronger in female-female than male-male sibling pairs, in the OCGS (Hasler et al, 2007) and other studies (Chacon et al, 2007). Moreover, there is evidence for linkage of OCD to several chromosomal regions, including the X chromosome, in families with multiple hoarding relatives (Samuels et al, 2007b).…”

Gender differences in obsessive-compulsive disorder: a literature review

“…39,40,41 Torresan et al 25 found among Brazilian men more sexual, religious, and symmetry obsessions, as well as more mental rituals. Chacon et al 42 evaluated OCD symptom dimensions in 40 pairs of Brazilian siblings with OCD. When both siblings were male, there was a significant correlation with contamination obsessions and cleaning rituals; and when both siblings were female, a correlation was found with hoarding symptoms.…”

“…37 Different ways of clustering symptoms hamper the comparisons between OCD studies to some extent. Some of them, for example, analyze aggressive obsession along with sexual and religious obsessions, 36,[38][39][40][41][42] which are more common among males. Such symptoms are called by some authors "forbidden" or "taboo" thoughts, 43 usually manifested as ego-dystonic impulses.…”

A review of psychiatric genetics research in the Brazilian population

“…48 In another investigation, Chacon et al found that familial factors seem to contribute to specific OCD phenotypic components such as age at onset of obsessivecompulsive symptoms and specific dimensions of the disorder. 49 In the State of Minas Gerais, a group from Universidade Federal de Minas Gerais (UFMG) has been investigating genetic factors associated with suicidal behavior. Several studies [50][51][52] demonstrated lack of genetic association between suicidal behavior and different polymorphisms such as A218C in tryptophan hydroxylase (TPH) gene, the short/long functional polymorphism in the promoter region of the SLC6A4 gene, and T102C in 5HT2A gene.…”