Is there sexual dimorphism in obsessive-compulsive disorder?

Characteristic alteration of subcortical nuclei shape in medication-free patients with obsessive-compulsive disorder

•

The study established a subregional-level anatomic alteration profile of subcortical structures in patients with obsessive-compulsive disorder (OCD).

•

The OCD patients showed an expansion of the lateral amygdala (right hemisphere) and right pallidum.

•

Deformities in pallidum were associated with illness duration and symptom severity of OCD.

•

Gender difference in OCD-related morphometric alterations were found in amygdala and caudate.

Background

Subcortical nuclei are important components in the pathology model of obsessive-compulsive disorder (OCD), and subregions of these structures subserve different functions that may distinctively contribute to OCD symptoms. Exploration of the subregional-level profile of structural abnormalities of these nuclei is needed to develop a better understanding of the neural mechanism of OCD.

Methods

A total of 83 medication-free, non-comorbid OCD patients and 93 age- and sex-matched healthy controls were recruited, and high-resolution T1-weighted MR images were obtained for all participants. The volume and shape of the subcortical nuclei (including the nucleus accumbens, amygdala, caudate, pallidum, putamen and thalamus) were quantified and compared with an automated parcellation approach and vertex-wise shape analysis using FSL-FIRST software. Sex differences in these measurements were also explored with an exploratory subgroup analysis.

Results

Volumetric analysis showed no significant differences between patients and healthy control subjects. Relative to healthy control subjects, the OCD patients showed an expansion of the lateral amygdala (right hemisphere) and right pallidum. These deformities were associated with illness duration and symptom severity of OCD. Exploratory subgroup analysis by sex revealed amygdala deformity in male patients and caudate deformity in female patients.

Conclusions

The lateral amygdala and the dorsal pallidum were associated with OCD. Neuroanatomic evidence of sexual dimorphism was also found in OCD. Our study not only provides deeper insight into how these structures contribute to OCD symptoms by revealing these subregional-level deformities but also suggests that gender effects may be important in OCD studies.

Meta-analysis of association between obsessive-compulsive disorder and the 3' region of neuronal glutamate transporter gene SLC1A1

The neuronal glutamate transporter gene SLC1A1 is a candidate gene for obsessive-compulsive disorder (OCD) based on linkage studies and convergent evidence implicating glutamate in OCD etiology. The 3' end of SLC1A1 is the only genomic region with consistently demonstrated OCD association, especially when analyzing male-only probands. However, specific allele associations have not been consistently replicated, and recent OCD genome-wide association and meta-analysis studies have not incorporated all previously associated SLC1A1 SNPs. To clarify the nature of association between SLC1A1 and OCD, pooled analysis was performed on all available relevant raw study data, comprising a final sample of 815 trios, 306 cases and 634 controls. This revealed weak association between OCD and one of nine tested SLC1A1 polymorphisms (rs301443; uncorrected P = 0.046; non-significant corrected P). Secondary analyses of male-affecteds only (N = 358 trios and 133 cases) demonstrated modest association between OCD and a different SNP (rs12682807; uncorrected P = 0.012; non-significant corrected P). Findings of this meta-analysis are consistent with the trend of previous candidate gene studies in psychiatry and do not clarify the putative role of SLC1A1 in OCD pathophysiology. Nonetheless, it may be important to further examine the potential associations demonstrated in this amalgamated sample, especially since the SNPs with modest associations were not included in the more highly powered recent GWAS or in a past meta-analysis including five SLC1A1 polymorphisms. This study underscores the need for much larger sample sizes in future genetic association studies and suggests that next-generation sequencing may be beneficial in examining the potential role of rare variants in OCD.

Serotonin and Female Psychopathology

There are sex differences in the prevalence and presentation of many psychiatric disorders. Various trends in symptomatology have emerged that are thought to be linked to periods of hormonal fluctuations such as with menses, pregnancy or menopause. With data from animal and human studies, it has become clear that there is an important interplay between the serotonergic system and gonadal hormones. The majority of the research to date has focused on the influence that estrogen has within the CNS and, in particular, how it leads to an overall increase in serotonin synthesis and availability. In reviewing this female-specific topic we hope to raise awareness to sex/gender differences in psychopathology, help identify at-risk populations and consider development of new treatment options. Future research will also need to consider the influence that progesterone and oxytocin may have on sex-specific psychopathology as well as incorporate neuroimaging and consider the influence of hormones on the serotonergic system at a genetic level.

Sex Differences in Genetic and Environmental Influences on Obsessive–Compulsive Symptoms in South Korean Adolescent and Young Adult Twins

Recent molecular genetic studies provide suggestive evidence for sexual dimorphism in genetics of obsessive-compulsive disorder. However, only a few twin studies have addressed the question of sex differences in genetic and environmental contributions to variation of obsessive–compulsive symptoms. The aim of the present study was to estimate genetic and environmental influences on obsessive–compulsive symptoms in South Korean twins, with a special emphasis on sex difference. In total, 751 adolescent and young adult twin pairs (ages: 13–23 years) completed a Korean version of the 30 items of the Maudsley Obsessional — Compulsive Inventory (MOCI) through a mail survey. A sum of the answers for the 30 items was calculated to represent a total score for obsessive–compulsive symptoms (hereafter, the MOCIT). Males had significantly higher variance of the MOCIT than did females. In males, monozygotic (MZ) twin correlation was significantly higher than dizygotic (DZ) twin correlations (.56 vs. .24), whereas in females, MZ and DZ twin correlations were not significantly different from each other (.39 vs. .36). The general sex-limitation model was applied to the twin data. The results of model-fitting analyses indicated that the unstandardized genetic variance as well as heritability estimate (53% vs. 41%) for the MOCIT was higher in males than in females. However, shared environmental influences did not attain statistical significance perhaps due to insufficient statistical power.

A case-control study of sex differences in strategic processing and episodic memory in obsessive-compulsive disorder

Although clinical and genetic data for obsessive-compulsive disorder (OCD) support the hypothesis of sexual dimorphism, the neuropsychological findings remain inconclusive. The aim of our study was to determine whether there are differences in cognitive performance between men and women with OCD as compared with healthy controls (HCs). A neuropsychological battery was administered to 50 patients with OCD (31 men and 19 women) and 50 HCs matched by sex, age, and educational level with patients. We evaluated intelligence, attention, episodic memory, and use of organizational strategies during encoding of verbal and nonverbal information. Male patients scored worse than controls did in measures of nonverbal memory tasks, whereas the cognitive performance of women with OCD was consistent with that of their HC counterparts. These results suggest a distinct pattern of cognitive dysfunction specific to the patients' sex.

Childhood neuropsychological deficits associated with adult obsessive-compulsive disorder

BACKGROUND

Existing neuropsychological studies of obsessive-compulsive disorder (OCD) are cross-sectional and do not provide evidence of whether deficits are trait-related (antecedent and independent of symptomatology) or state-related (a consequence, dependent on symptomatology).

AIMS

To investigate whether there are premorbid neuropsychological deficits associated with adult OCD.

METHOD

Longitudinal data were collected from participants of the Dunedin Multidisciplinary Health and Developmental study. Neuropsychological data collected at age 13 were linked with age 32 diagnosis of OCD.

RESULTS

The group who had OCD at age 32 differed significantly from the control group with no OCD on their performance at age 13 on neuropsychological tests of visuospatial, visuoconstructive and visuomotor skills, controlling for gender and socioeconomic status, but did not differ on tests of general IQ or verbal ability. Performance of the group with OCD on tests of executive functioning was mixed.

CONCLUSIONS

Individuals with OCD have premorbid impairment in visuospatial abilities and some forms of executive functioning, consistent with biological models of OCD.

Genetic and environmental influences on obsessive-compulsive disorder

It is important to understand how genetic and environmental factors interact in the development of obsessive-compulsive disorder (OCD) in order to provide a cohesive model of the underlying pathogenic mechanisms. In this article, we provide an overview of the current knowledge of possible genetic and environmental contributions to the development of OCD. We consider the significant challenges for identifying risk factors for OCD as well as promising avenues for overcoming these obstacles in future research. In particular, we discuss the value of focusing on certain phenotypes, applying a dimensional approach, and investigating possible endophenotypes. We also describe innovative study designs that may be used in future research to explore the interaction between genetic vulnerability and environmental risk factors for OCD.

Association of the SLC1A1 glutamate transporter gene and obsessive-compulsive disorder

CONTEXT

Obsessive-Compulsive Disorder (OCD) is a debilitating illness with putative glutamatergic abnormalities. Two separate proximal haplotypes in the glutamate transporter gene, SLC1A1, were recently reported to be associated with OCD among males, but replication is required.

OBJECTIVES

This study examines SLC1A1 as a candidate gene for OCD and explores gender influences. It was hypothesized that a significant association between SLC1A1 and OCD would be replicated in an independent sample of males but not females.

DESIGN

Family-based association candidate gene study.

SETTING

Participants were recruited from tertiary care OCD specialty clinics.

PARTICIPANTS

OCD probands and their first degree relatives.

MAIN OUTCOMES MEASURES

Association of OCD with genotypes of single nucleotide polymorphism (SNP) markers and related haplotypes.

RESULTS

Association between OCD and the three-marker haplotype rs12682807/ rs2072657/ rs301430, with overtransmission of A/T/T, was observed in both genders combined (global P = 0.0015) and in males (global P = 0.0031). Single-marker associations with OCD in the region (rs3780412 and rs2228622) demonstrated modest significance (permuted P = 0.045).

CONCLUSIONS

This study identifies a significant association between the SLC1A1 glutamate transporter gene and OCD in a haplotype overlapping with that recently reported.

Memory and executive functioning in obsessive-compulsive disorder: a selective review

BACKGROUND

The neurocognitive deficits that underlie the unique features of obsessive-compulsive disorder (OCD) are not yet completely understood. This paper reviews the main neuropsychological findings in memory and executive functioning in this disorder, and examines a number of challenges facing this area of research.

METHOD

A selective review of the neuropsychological literature on OCD was conducted using MEDLINE and drawing on literature known to the authors.

RESULTS

The neuropsychological profile of OCD appears to be one of primary executive dysfunction. Although memory functioning may be affected, these deficits appear secondary to an executive failure of organizational strategies during encoding. On tasks of executive functioning patients with OCD demonstrate increased response latencies, perseveration of responses, and difficulties utilizing feedback to adapt to change.

LIMITATIONS

A statistical meta-analysis was not performed and only the cognitive domains of memory and executive functioning were examined.

CONCLUSIONS

Given the prominence of chronic doubt and indecision in clinical settings, it is surprising that decision making as a cognitive construct as related to OCD has not received greater attention in the neuropsychological literature. On the basis of emerging literature we suggest that it is a potential area of dysfunction and one that warrants further investigation as it may assist in enhancing our understanding of the pathophysiology of OCD.

Clinical predictors of response to cognitive-behavioral therapy for obsessive-compulsive disorder

This paper reviews predictors of treatment response in open and controlled trials of cognitive-behavioral therapy for obsessive-compulsive disorder (OCD). We focus on demographic characteristics, aspects of OCD symptoms, comorbidity, family factors, cognitive influences, and treatment-specific characteristics as predictor variables. Although inconsistent findings characterize much of the literature, several relatively consistent and salient predictors have emerged, including symptom severity, symptom subtype, severe depression, the presence of comorbid personality disorders, family dysfunction, and the therapeutic alliance. Implications of findings and recommendations for future research are discussed.

OCD symptoms in a sample of Turkish patients: a phenomenological picture

This study aimed to investigate the clinical features of obsessive-compulsive disorder (OCD) and the possible association between obsessive-compulsive symptoms and culture-related characteristics in a sample of Turkish patients with OCD. We studied 141 patients with OCD (according to DSM-IV criteria) consecutively admitted to our outpatient clinic during the period from February 1998 to December 2003. We used the Turkish version of the Structured Clinical Interview for DSM-IV (SCID) to interview all patients, and the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) to assess obsessive-compulsive symptoms and severity. The onset of OCD symptoms was earlier in males. Major depression was the most common comorbid disorder (30.5%). The most commonly occurring obsessions were contamination (56.7%), aggression (48.9%), and somatic (24.1%), followed by religious (19.9%), symmetry (18.4%), and sexual imagery (15.6%). Symmetry and sexual obsessions, and checking compulsions and rituals, tended to be more common in male patients. Dirt and contamination obsessions and washing compulsions were slightly more common in females. The vast majority of patients with religious obsessions (83%) and half of the patients with sexual obsessions had compulsions that included religious practices. Also, patients with sexual and religious obsessions had delayed seeking professional help.

Are There Sex Differences in Neuropsychological Functions Among Patients With Obsessive-Compulsive Disorder?

The purpose of this study was to examine whether men and women with obsessive-compulsive disorder (OCD) demonstrate differences in neuropsychological functioning compared to healthy men and women. Participants were 56 consecutive patients (33 male, 23 female) and 40 healthy control participants (20 male, 20 female) of comparable characteristics. Male and female patients had comparable symptom severity, illness duration, comorbidity, in- or out-patient status, and medication usage. An extensive neuropsychological test battery was administered including tests of general nonverbal intelligence, attention, verbal and nonverbal memory, and executive functions. Male and female OCD patients showed comparable neuropsychological performances on most cognitive domains. However, we found some evidence for cross-sex shifts in verbal fluency tasks (FAS and Category Alternation Test [CAT]), the reading component of the Stroop test, and the Wechsler Adult Intelligence Scale-Revised (WAIS-R) Digit Span-Forward test. Post hoc analyses revealed that female patients showed reduced performance on these tests compared to healthy women, in the male-typical direction. Among OCD women only, there were significant negative correlations between OCD symptom severity and performance on the CAT and the reading Stroop. We conclude that sex does not seem to be a major determinant of neuropsychological function in OCD, but the observed cross-sex shifts on some tasks deserve further examination.

Compulsive-like behaviour according to the sex and the reproductive stage of female rats

The aim of the present study was to explore putative differences in the responses assessed in an animal model of obsessive-compulsive disorder (OCD) according to the sex and the reproductive cycle of female rats. The model consists of the induction of perseveration (repetitive choices of the same arm in a T-maze) by 8-OH-DPAT (1.0mg/kg). Males and females (pooled in all stages of their oestrous cycle) persevered after 8-OH-DPAT administration and no differences were observed between groups. During the oestrous cycle, this 5-HT(1A) agonist induced perseveration in metoestrus, dioestrus and prooestrus and reduced levels of this behaviour in oestrus. 8-OH-DPAT provoked perseveration in mid-gestation, an effect that was reduced in late-gestation and blocked during lactation. Reproductive cycle changes in the induced perseveration are discussed from the standpoint of the ovarian steroids' action on the serotoninergic system and on the bases of the variations in stress responsiveness along the reproductive cycle of the female. Present results validate the use of females in this model of OCD and could be relevant for studying the role of reproductive hormones in the pathophysiology of this disorder.

Sex steroids and human behavior: implications for developmental psychopathology

In a variety of mammalian species, prenatal androgens organize brain structures and functions that are later activated by steroid hormones in postnatal life. In humans, studies of individuals with typical and atypical development suggest that sex differences in reproductive and nonreproductive behavior derive in part from similar prenatal and postnatal steroid effects on brain development. This paper provides a summary of research investigating hormonal influences on human behavior and describes how sex differences in the prevalences and natural histories of developmental psychopathologies may be consistent with these steroid effects. An association between patterns of sexual differentiation and specific forms of psychopathology suggests novel avenues for assessing the effects of sex steroids on brain structure and function, which may in turn improve our understanding of typical and atypical development in women and men.