A higher frequency of a low activity-related allele of the MAO-A gene in females with obsessive-compulsive disorder

Genetic and epigenetic architecture of Obsessive-Compulsive Disorder: In search of possible diagnostic and prognostic biomarkers

Obsessive-Compulsive Disorder (OCD) is a prevalent and severe clinical condition whose hallmarks are excessive, unwanted thoughts (obsessions) and repetitive behaviors (compulsions). The onset of symptoms generally occurs during pre-adult life and typically affects subjects in different aspects of their life's, compromising social and professional relationships. Although robust evidence suggests a genetic component in the etiopathogenesis of OCD, the causes of the disorder are still not completely understood. It is thus of relevance to take into account how genes interact with environmental risk factors, thought to be mediated by epigenetic mechanisms. We here provide an overview of genetic and epigenetic mechanisms of OCD, focusing on the modulation of key central nervous system genes, in the attempt to suggest possible disease biomarkers.

Association study between MAO-A gene promoter VNTR polymorphisms and obsessive-compulsive disorder

A functional variant in the mono-amine oxidase-A (MAO-A) gene has been shown to affect neural function related to several mental disorders. Therefore, we would like to ascertain if MAO-A could be a candidate gene for obsessive-compulsive disorder (OCD). We genotyped 414 healthy subjects and 240 OCD patients and found no significant difference not only in allele frequencies in male patients (χ(2) = 0.365, DF = 1, P = 0.545, odds ratio (OR) = 1.139, confidence interval (CI) = 0.75-1.74) but also in allele frequencies (χ(2) = 0.698, DF = 1, P = 0.404, OR = 0.849, CI = 0.579-1.246) or genotypic frequencies (χ(2)=0.933, DF = 2, P = 0.627) in female patients between OCD patients and controls. Given that this is the first investigation of this gene in OCD in a Chinese Han population, further studies are required to obtain more definitive conclusions in a larger number of subjects.

The c.1460C>T polymorphism of MAO-A is associated with the risk of depression in postmenopausal women

OBJECTIVE

The aim of the study was an evaluation of possible relationships between polymorphisms of serotoninergic system genes and the risk of depression in postmenopausal women.

METHODS

We studied 332 women admitted to our department because of climacteric symptoms. The study group included 113 women with a diagnosis of depressive disorder according to the Hamilton rating scale for depression; the controls consisted of 219 women without depression. Serum 17β-estradiol concentrations were evaluated using radioimmunoassay, while polymorphisms in serotoninergic system genes: serotonin receptors 2A (HTR2A), 1B (HTR1B), and 2C (HTR2C); tryptophan hydroxylase 1 (TPH1) and 2 (TPH2), and monoamine oxidase A (MAO-A) were evaluated using polymerase chain reaction-restriction.

RESULTS

We found that the 1460T allele of MAO-A c.1460C>T (SNP 1137070) appeared with a significantly higher frequency in depressed female patients than in the control group (P = 0.011) and the combined c.1460CT + TT genotypes were associated with a higher risk of depression (P = 0.0198). Patients with the 1460TT genotype had a significantly higher 17β-estradiol concentration than patients with the 1460CT genotype (P = 0.0065) and 1460CC genotype (P = 0.0018).

CONCLUSIONS

We concluded that depression in postmenopausal women is closely related to the genetic contribution of MAO-A.

Overview of genetics and obsessive-compulsive disorder

This paper reviews the current state of research into the genetics of obsessive-compulsive disorder (OCD). Heredity has a major role in OCD etiology. This evidence comes from several methodological approaches such as family, twin, and segregation analysis studies. A major single gene effect as well as a polygenic hypothesis has been suggested based on segregation studies. In addition, candidate gene association and linkage analyses have shown not only one gene, but a few interesting genes and areas of the genome that may be relevant in OCD. In this search for genes, new definitions of the OCD phenotype have emerged, and some of them may be considered intermediate phenotypes between the gene effect and OCD-DSM-IV diagnosis. The phenotypic and genetic heterogeneity of OCD magnifies the challenge of locating susceptibility genes; at the same time, the identification of vulnerability genes will elucidate the identification of subtypes or dimensions of the disorder. Therefore research strategies that take advantage of clinical subtyping and that redefine the OCD phenotype in the context of genetic studies may potentially contribute to the nosology of OCD and ultimately pathophysiology. There is a lack of understanding about how genes and environment interact in OCD. However, there are some reports that will be discussed, which have attempted to evaluate how the environment contributes to OCD.

Association of MAO-A variant with complicated grief in major depression

BACKGROUND/AIMS

It has been suggested that monoamine oxidase A (MAO-A) activity is involved in the pathogenesis of major depression. Bereavement-related complicated grief significantly increases the risk of major depression and has been shown to be influenced by serotonergic tonus, possibly conferred by MAO-A activity. Complicated grief--whose inclusion in DSM-V as a separate mental disorder is under discussion--has been shown to be a distinct syndrome with symptoms not seen in depression. Therefore, in the present study, genetic variation in the MAO-A gene was investigated for its influence on complicated grief in major depression.

METHODS

Sixty-six unrelated Caucasian patients (41 female, 25 male) with major depression and a history of bereavement were evaluated for complicated grief using the Inventory of Complicated Grief (ICG), the posttraumatic stress reaction after the loss by means of the Impact of Event Scale (IES-R) and further psychopathological measures. Patients were additionally genotyped for the functional variable number tandem repeat (VNTR) in the promoter region of the MAO-A gene.

RESULTS

The more active longer allele of the MAO-A VNTR was significantly associated with complicated grief in the female subgroup of patients (chi(2) = 9.471, p = 0.002, OR = 9.208, 95% CI 2.129-38.899, Bonferroni-corrected p = 0.012), whereas there was no such effect in male patients. Higher posttraumatic stress reaction was only nominally associated with the more active longer allele of the MAO-A VNTR in the female subgroup of patients (genotypes: chi(2) = 5.939, p = 0.015, OR = 5.333, 95% CI 1.366-20.557, Bonferroni-corrected p = 0.087). No significant associations of MAO-A VNTR with the severity of depressive symptoms (Beck Depression Inventory), anxiety symptoms (Spielberger State-Trait Anxiety Inventory), general mental health (Brief Symptom Inventory), or perceived social support (F-SozU) were found (all p > 0.10).

CONCLUSION

The present pilot study for the first time suggests a gender-specific contribution of the more active MAO-A VNTR variant to an increased vulnerability for complicated grief as a potential intermediate phenotype of major depression.

Monoamine oxidase A variant influences antidepressant treatment response in female patients with Major Depression

The monoamine oxidase A (MAO-A) has been suggested to be involved in the pathogenesis as well as the pharmacological treatment of Major Depression. In the present study, 340 patients with a Major Depressive Episode (f=194, m=146; DSM-IV) of Caucasian descent were genotyped for the functional MAO-A VNTR. The clinical response to antidepressive pharmacological treatment was assessed by weekly intra-individual changes of HAM-D-21 scores over six weeks. The longer MAO-A alleles (3a, 4, 5) conferred a significant risk of slower and less efficient overall response over the course of 6 weeks of antidepressant treatment in patients with Major Depression, with the effect being restricted to female patients (p=0.028; corrected for multiple testing). The present results suggest that high-activity MAO-A genotypes possibly by consecutively decreased serotonin and/or norepinephrine availability negatively influence antidepressant treatment response during the first six weeks of pharmacological treatment in female patients with Major Depression.

The MAOA T941G polymorphism and short-term treatment response to mirtazapine and paroxetine in major depression

This study investigated the possible association of the MAOA T941G gene variant with differential antidepressant response to mirtazapine and/or paroxetine in 102 patients with major depression (DSM-IV criteria) participating in a randomized double-blind controlled clinical trial. Female mirtazapine-treated patients homozygous for the T-allele had a significantly faster and better treatment response than TG/GG-patients. In males, we failed to show an association between MAOA T941G gene variant and mirtazapine response. In the paroxetine-treated group, there were no significant differences in treatment response between MAOA T941G genotype groups. Time course of response and antidepressant efficacy of mirtazapine, but not paroxetine, seem to be influenced in a clinically relevant manner by this allelic variation within the MAOA gene, at least in female patients. An independent replication of our finding is needed. If replicated, genotyping of this locus could become a promising tool to predict response to mirtazapine treatment in females suffering from major depression.

Neurobiologie bei Tic- und Zwangsstörungen

Zusammenfassung. Erst in den letzten Jahren wird auch in der Forschung vermehrtes Augenmerk auf die Überschneidung von Tic- und Zwangsstörungen gerichtet. Während in Übersichtsarbeiten zum gemeinsamen Auftreten von Tic- und Zwangsstörungen die zahlreichen Befunde zu Phänomenologie, begleitender Psychopathologie, Epidemiologie und daraus resultierenden Therapieimplikationen breiten Raum einnehmen, sind die Untersuchungsergebnisse hinsichtlich ätiologischer und pathophysiologischer Gemeinsamkeiten in entsprechenden Arbeiten unterrepräsentiert. Daher wird mit dieser Arbeit ein Überblick über den aktuellen neurobiologischen Forschungsstand zu den Gemeinsamkeiten und Unterschieden von Tic- und Zwangsstörungen gegeben.

Association study of a functional MAOA-uVNTR gene polymorphism and personality traits in Chinese young females

Monoamine oxidase A (MAOA), a mitochondrial outer membrane enzyme, degrades biogenic amines including norepinephrine, dopamine and serotonin, which have been implicated in the expression of personality traits. We tested the associations between functional MAOA-uVNTR genetic variants and personality traits in a cohort of 370 healthy young Chinese females. Subjects who were homozygous for the 4-repeat allele of the MAOA-uVNTR gene tended to have a higher total score on the Harm Avoidance (HA) dimension of the Tridimensional Personality Questionnaire (TPQ) (p = 0.056), and had a significantly higher score on subdimension 4 of HA (p = 0.020) compared with the 3-repeat carriers. No significant association was demonstrated for MAOA-uVNTR polymorphism and the other two dimensions (Novelty Seeking and Reward Dependence) of TPQ. These results suggest that genetic variants of the MAOA gene may play a role in HA, but not in Novelty Seeking or Reward Dependence.

Anxiety disorders in women: does gender matter to treatment?

Women have a substantially higher risk of developing lifetime anxiety disorders compared with men. In addition, research evidence has generally observed an increased symptom severity, chronic course, and functional impairment in women with anxiety disorders in comparison to men. However, the reasons for the increased risk in developing an anxiety disorder in women are still unknown and have yet to be adequately investigated. Evidence from various studies has suggested that genetic factors and female reproductive hormones may play important roles in the expression of these gender differences. The significant differences in onset and course of illness observed in men and women diagnosed with anxiety disorders warrants investigations into the need of differential treatment; however, evidence of gender differences in treatment response to different anxiety disorders are varying and remain largely inconclusive. This article reviews the prevalence, epidemiology, and phenomenology of the major anxiety disorders in women, as well as the implications of such differences for treatment.

Association study of a monoamine oxidase a gene promoter polymorphism with major depressive disorder and antidepressant response

Monoamine oxidase A (MAOA), a mitochondrial enzyme involved in the degradation of biogenic amines, may be implicated in the pathogenesis of major depressive disorder (MDD) and be related to the therapeutic effects of antidepressants. To elucidate a genetic predisposition of MDD, we studied a variable-number-tandem-repeat (VNTR) polymorphism in the promoter region of the MAOA gene in a Chinese population of 230 MDD patients and 217 controls. We also examined the association of this polymorphism and antidepressant therapeutic response in the MDD patients who underwent a 4-week fluoxetine treatment. Our results showed a significantly increased frequency of 4-repeat (4R) allele in MDD patients, especially in the female population. Furthermore, MDD female patients who were 3R homozygotes had a significantly better response to 4-week fluoxetine treatment when compared to 4R carriers (p=0.024), but there was a nonsignificant difference found in male patients (p=0.081). Since the 4R allele transcribed 2-10 times more efficiently than those with 3R allele, our findings suggest that the MAOA-uVNTR may be involved in the pathogenesis of MDD and the antidepressant therapeutic mechanisms in Chinese population, and that there may be a gender effect in this association.

Genetic epidemiology of anxiety disorders

This chapter reviews the genetic epidemiology of the major subtypes of anxiety disorders including panic disorder, phobic disorders, generalized anxiety disorder, and obsessive-compulsive disorder. Controlled family studies reveal that all of these anxiety subtypes are familial, and twin studies suggest that the familial aggregation is attributable in part to genetic factors. Panic disorder and, its spectrum have the strongest magnitude of familial clustering and genetic underpinnings. Studies of offspring of parents with anxiety disorders an increased risk of mood and anxiety disorders, but there is far less specificity of the manifestations of anxiety in children and young adolescents. Although there has been a plethora of studies designed to identify genes underlying these conditions, to date, no specific genetic loci have been identified and replicated in independent samples.

Corrigendum to "gender in obsessive-compulsive disorder: clinical and genetic findings" [Eur. Neuropsychopharmacol. 14 (2004) 105-113]

BACKGROUND

There is increasing recognition that obsessive-compulsive disorder (OCD) is not a homogeneous entity. It has been suggested that gender may contribute to the clinical and biological heterogeneity of OCD.

METHODS

Two hundred and twenty patients (n=220; 107 male, 113 female) with DSM-IV OCD (age: 36.40 +/- 13.46) underwent structured interviews. A subset of Caucasian subjects (n=178), including subjects from the genetically homogeneous Afrikaner population (n=81), and of matched control subjects (n=161), was genotyped for polymorphisms in genes involved in monoamine function. Clinical and genetic data were statistically analyzed across gender.

RESULTS

Compared with females, males with OCD (1) had an earlier age of onset, and a trend toward having more tics and worse outcome, (2) had somewhat differing patterns of OCD symptomatology and axis I comorbidity, and (3) in the Caucasian group, were more likely to have the high activity T allele of the EcoRV variant of the monoamine oxidase A (MAO-A) gene compared to controls, and (4) in the Afrikaner subgroup, were more frequently homozygous for the G allele at the G861C variant of the 5HT1Dbeta gene than controls. Females with OCD (1) reported more sexual abuse during childhood than males, (2) often noted changes in obsessive-compulsive symptoms in the premenstrual/menstrual period as well as during/shortly after pregnancy, and with menopause, and (3) in the Caucasian subgroup, were more frequently homozygous for the low activity C allele of the EcoRV variant of the MAO-A gene compared to controls, with this allele also more frequent in female patients than controls.

CONCLUSION

This study supports the hypothesis that gender contributes to the clinical and biological heterogeneity of OCD. A sexually dimorphic pattern of genetic susceptibility to OCD may be present. Further work is, however, needed to delineate the mechanisms that are responsible for mediating the effects of gender.

Sex differences on spontaneous alternation in prepubertal rats: implications for an animal model of obsessive-compulsive disorder

Sex differences in the prevalence of obsessive-compulsive disorder (OCD) in prepubertal children have been described. Deficits on spontaneous alternation behavior (SAB) have been proposed as an animal model of OCD.

OBJECTIVES

To explore possible sex differences in the ontogeny of SAB and in the effect of the 5-HT1A agonist, 8-OH-hydroxy-2 (di-n-propylamino)-tetralin (8-OH-DPAT) in an animal model of OCD.

METHODS

The ontogeny of SAB and the perseveration produced by 8-OH-DPAT were compared between male and female prepubertal rats.

RESULTS

Males alternated their arm choose from postnatal day 32 onwards, while females perseverated in the chosen arm until postnatal day 38. The mean number of repetitive choices remained close to 1 in males from postnatal day 23 onwards, but females showed a mean number of repetitive choices higher than 1.5 until the end of the test. The 8-OH-DPAT (0.125, 0.5 and 2.0 mg/kg, 15 min) produced perseveration in males but not in females.

CONCLUSIONS

These data show important sex differences in the ontogeny of SAB and the effect of 8-OH-DPAT in a model of OCD. Such differences could be relevant for the sex differences in the prevalence of childhood OCD.

Mu opioid receptor gene as a candidate for the study of obsessive compulsive disorder with and without tics

Obsessive compulsive disorder (OCD) is a complex psychiatric disease characterized by recurring obsessions or compulsions that cause significant distress to the patient. The etiology of this disorder remains largely unknown, although a genetic component has been suggested. Many candidates genes have been evaluated based on a possible serotoninergic and dopaminergic brain dysfunction. We postulate the micro opioid receptor (MOR) gene as a candidate because some observations support a role of the opioid system in OCD. The opioid antagonist, naloxone, rapidly exacerbates OCD symptoms and the opioid agonist, tramadol, was reported to be effective in the treatment of some patients. We studied two single nucleotide polymorphisms (C17T and A118G) in 51 trios with OCD. Genotyping was analyzed with transmission desequilibrium test (TDT). The allelic variant +17T of the C17T polymorphism had a low frequency (1%) in our population that did not allow for statistic analysis. However, for the allelic variant +G of the A118G polymorphism we were able to performed statistical comparisons. Our results showed a trend toward significance (chi(2) McNemar = 3.6, P = 0.065) for TDT in patients with comorbid tics. It is an interesting finding that should be tested in a larger sample of OCD patients with tics.

Gender in obsessive-compulsive disorder: clinical and genetic findings

BACKGROUND

There is increasing recognition that obsessive-compulsive disorder (OCD) is not a homogeneous entity. It has been suggested that gender may contribute to the clinical and biological heterogeneity of OCD.

METHODS

Two hundred and twenty patients (n=220; 107 male, 113 female) with DSM-IV OCD (age: 36.40+/-13.46) underwent structured interviews. A subset of Caucasian subjects (n=178), including subjects from the genetically homogeneous Afrikaner population (n=81), and of matched control subjects (n=161), was genotyped for polymorphisms in genes involved in monoamine function. Clinical and genetic data were statistically analyzed across gender.

RESULTS

Compared with females, males with OCD (1) had an earlier age of onset, and a trend toward having more tics and worse outcome, (2) had somewhat differing patterns of OCD symptomatology and axis I comorbidity, and (3) in the Caucasian group, were more likely to have the high activity T allele of the EcoRV variant of the monoamine oxidase A (MAO-A) gene compared to controls, and (4) in the Afrikaner subgroup, were more frequently homozygous for the C allele at the G861C variant of the 5HT(1D beta) gene than controls. Females with OCD (1) reported more sexual abuse during childhood than males, (2) often noted changes in obsessive-compulsive symptoms in the premenstrual/menstrual period as well as during/shortly after pregnancy, and with menopause, and (3) in the Caucasian subgroup, were more frequently homozygous for the low activity C allele of the EcoRV variant of the MAO-A gene compared to controls, with this allele also more frequent in female patients than controls.

CONCLUSION

This study supports the hypothesis that gender contributes to the clinical and biological heterogeneity of OCD. A sexually dimorphic pattern of genetic susceptibility to OCD may be present. Further work is, however, needed to delineate the mechanisms that are responsible for mediating the effects of gender.

Genetics of obsessive-compulsive disorders: new findings and challenges

A review of the current state of research in the genetics of obsessive-compulsive disorder (OCD) is presented. OCD is a neuropsychiatric condition that affects 1-2% of the population and often has an early age at onset of symptoms. OCD has been shown to be familial, and a major gene effect has been reported. However, phenotypic and genetic heterogeneity of OCD poses multiple challenges for locating susceptibility genes. Strategies such as the use of phenotypic subtyping (using tic disorders or other anxiety disorders) and endophenotyping based on brain mechanisms underlying OCD (functional brain imaging and neuropsychological measures) may open ways to understand the genetic components of OCD. Using child probands and extended families for linkage an association studies is another venue to obtain greater informative families for genetic studies. A better understanding of environmental triggers, OCD subtypes and OCD pathophysiology will lead to locating genes that confer risk to OCD.

Anxiety disorders in women

Women have higher overall prevalence rates for anxiety disorders than men. Women are also much more likely than men to meet lifetime criteria for each of the specific anxiety disorders: generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), social anxiety disorder (SAD), posttraumatic stress disorder (PTSD), simple phobia, panic disorder, and agoraphobia. Considerable evidence suggests that anxiety disorders remain underrecognized and undertreated despite their association with increased morbidity and severe functional impairment. Increasing evidence suggests that the onset, presentation, clinical course, and treatment response of anxiety disorders in women are often distinct from that associated with men. In addition, female reproductive hormone cycle events appear to have a significant influence on anxiety disorder onset, course, and risk of comorbid conditions throughout a woman's life. Further investigations concerning the unique features present in women with anxiety disorders are needed and may represent the best strategy to increase identification and optimize treatment interventions for women afflicted with these long-neglected psychiatric disorders.

Association analysis of MAOA and COMT with neuroticism assessed by peers

There are several reported associations between depressive disorders, panic disorder, and obsessive-compulsive disorder (OCD) and a variety of polymorphisms in the monoamine oxidase A (MAOA) gene. Associations have also been reported between the catechol-O-methyltransferase (COMT) gene and both OCD and bipolar depression. However, the role of these markers has not been explored for the personality trait of neuroticism (N), a normally distributed quantitative trait, which is highly genetically correlated with anxiety and depression and may be a vulnerability to either type of disorder. We explored the possible role of MAOA, COMT, and their interaction on N using a selected extremes design. From a sample of 2,085 individuals, each assessed for N by two independent peers rather than using self-report questionnaires, we selected 57 individuals from the top 10% of scores, and 62 individuals from the bottom 10%. Using selected extreme low subjects as the controls, rather than an unselected control group gives roughly twice the power of a standard case-control design. We typed a functional variable number tandem repeat (VNTR) in the MAOA gene promoter, and a functional polymorphism in the coding region of the COMT gene. Two novel alleles in the MAOA VNTR were identified on the basis of their size, and their structure examined by sequencing analysis. We found weak evidence for association with COMT genotype, when the females and males were considered separately, and for MAOA genotype in males only. There was no significant interaction between COMT and MAOA.

Additional evidence that genetic variation of MAO-A gene supports a gender subtype in obsessive-compulsive disorder

Studies have recently reported a sexually dimorphic association between obsessive-compulsive disorder (OCD) and a polymorphism related with variations in MAO-A activity. These observations suggest the possibility of gender differences in genetic susceptibility for OCD. We thus reexamined the MAO-A/EcoRV polymorphism in a sample of 122 OCD patients and 124 healthy subjects. An excess of allele 1 in OCD females with major depression disorder was confirmed as previously reported. This difference was more strongly associated with OCD females than males in the total sample. Finally, we analyzed a sample of 51 OCD trios. Haplotype-based haplotype relative risk (HHRR) analysis of the inheritance of the MAO-A variants revealed in the female probands that 14 out of 19 transmitted the allele 1, providing significant evidence for an allelic association between OCD and MAO-A gene. In conclusion, our findings may provide molecular evidence to identify a clinically meaningful gender subtype. However, an effort should be made to replicate the analysis in larger samples of informative parents using strategies such as transmission disequilibrium test to allow definite conclusions.

The cognitive-affective neuroscience of obsessive-compulsive disorder

There is substantial evidence that obsessive-compulsive disorder (OCD) is mediated by specific cortico-striatal- thalamic-cortical (CTSC) circuits. Here we discuss very recent publications that address the following questions: How does damage to CSTC circuitry come about?; What are the neurochemical systems involved in mediating this circuitry?; and What are the implications of such damage for understanding the pathogenesis and management of OCD? A cognitive-affective neuroscience perspective is helpful in advancing our understanding of the role of these circuits in OCD and the dysfunctional procedural strategies that appear to characterize this disorder. Furthermore, this model is becoming integrated with a range of data including brain imaging, genetic, immunologic, and neurochemical findings.

Evidence of a schizotypy subtype in OCD

OCD patients represent a heterogeneous mix of clinical phenotypes, likely reflecting a wide range of genetic vulnerabilities. In other medical illnesses, neurobiologically-based traits with a genetic component that are associated with the target disorder have been successfully used to detect patients with a specific genetic liability to disease. The overlap between symptoms of OCD and Schizophrenia suggested that schizotypal traits could have the potential to distinguish a relatively homogeneous subtype of OCD. We obtained schizotypy scores for 119 affected adult probands who met lifetime criteria for DSM-IV OCD. Five subscales from the Structured Interview of Schizotypy were used to assess ideas of reference, suspiciousness, magical thinking, illusions and psychotic-like thought. Selected for their obvious face validity with the cardinal signs of schizophrenia, Cronbach's alpha suggested that these subscales also provided a reliable measure of positive sign schizotypy (0.83). Fifty percent of our OCD sample had mild to severe positive schizotypy signs. t- and chi2 tests of significance suggested seven variables that distinguished OCD patients with schizotypy, including earlier age of onset, greater number of comorbid diagnoses and increased rates of learning disability, aggressive and somatic obsessions and counting and arranging compulsions. Three of these seven variables, including learning disabilities, counting compulsions and history of specific phobia, significantly increased the odds of schizotypy among patients with lifetime OCD. These findings enhanced the validity of the schizotypy construct in OCD. Whether this schizotypy subtype can distinguish a subgroup of patients with relatively homogeneous genetic characteristics waits further investigation.

Is there sexual dimorphism in obsessive-compulsive disorder?

The present review addresses the question of sexual dimorphism in obsessive-compulsive disorder. It enumerates examples that could be interpreted to suggest the existence of such dimorphism from the fields of epidemiology, phenomenology, pharmacology, neuropsychology, neuroimaging and genetics. We conclude that data, at this point, are too scarce to warrant a firm conclusion. On the contrary it seems that there are enough indications in the literature that hint at the possibility of sexual dimorphism to stimulate further research in the field.