Obsessive-compulsive symptoms and related sex differences in brain structure: an MRI study in dutch twins.
ABSTRACT Neuroimaging studies have indicated abnormalities in cortico-striato-thalamo-cortical circuits in obsessive-compulsive disorder patients, but results have not been consistent. Since there are significant sex differences in human brain anatomy and obsessive-compulsive symptomatology and its developmental trajectories tend to be distinct in males and females, we investigated whether sex is a potential source of heterogeneity in neuroimaging studies on obsessive-compulsive symptoms. We selected male and female twin pairs who were concordant for scoring either high or low for obsessive-compulsive symptoms and a group of discordant pairs where one twin scored high and the co-twin scored low. The design included 24 opposite-sex twin pairs. Magnetic resonance imaging scans of 31 males scoring high for obsessive-compulsive symptoms, 41 low-scoring males, 58 high-scoring females, and 73 low-scoring females were analyzed and the interaction of obsessive-compulsive symptoms by sex on gray matter volume was assessed using voxel-based morphometry. An obsessive-compulsive symptom by sex interaction was observed for the left middle temporal gyrus, the right middle temporal gyrus, and the right precuneus. These interactions acted to reduce or hide a main effect in our study and illustrate the importance of taking sex into account when investigating the neurobiology of obsessive-compulsive symptoms.
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ABSTRACT: Combining datasets across independent studies can boost statistical power by increasing the numbers of observations and can achieve more accurate estimates of effect sizes. This is especially important for genetic studies where a large number of observations are required to obtain sufficient power to detect and replicate genetic effects. There is a need to develop and evaluate methods for joint-analytical analyses of rich datasets collected in imaging genetics studies. The ENIGMA-DTI consortium is developing and evaluating approaches for obtaining pooled estimates of heritability through meta-and mega-genetic analytical approaches, to estimate the general additive genetic contributions to the intersubject variance in fractional anisotropy (FA) measured from diffusion tensor imaging (DTI). We used the ENIGMA-DTI data harmonization protocol for uniform processing of DTI data from multiple sites. We evaluated this protocol in five family-based cohorts providing data from a total of 2248 children and adults (ages: 9-85) collected with various imaging protocols. We used the imaging genetics analysis tool, SOLAR-Eclipse, to combine twin and family data from Dutch, Australian and Mexican-American cohorts into one large "mega-family". We showed that heritability estimates may vary from one cohort to another. We used two meta-analytical (the sample-size and standard-error weighted) approaches and a mega-genetic analysis to calculate heritability estimates across-population. We performed leave-one-out analysis of the joint estimates of heritability, removing a different cohort each time to understand the estimate variability. Overall, meta- and mega-genetic analyses of heritability produced robust estimates of heritability.NeuroImage 03/2014; DOI:10.1016/j.neuroimage.2014.03.033 · 6.13 Impact Factor
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ABSTRACT: Exposure to adverse childhood experiences (ACE) increases the risk of adult physical and mental health disorders, including obsessive-compulsive disorder (OCD), and influences adult brain structure and function. ACE could influence the use of psychotropic drugs in adulthood, and treatment seeking behaviors. We assessed the severity of ACE in a sample of 31 healthy controls and 66 patients with OCD who were consecutively referred for hospitalization and were either drug-naïve or drug-treated. In addition, we explored the possible clinical relevance of ACE with two additional analyses: (a) a discriminant function analysis with sex and ACE as factors, and (b) a logistic regression with use of medication as dependent variable and ACE as factor. Despite comparable age, years at school, age at onset of illness, duration of illness, and severity of illness (Y-BOCS), adult drug-naïve patients reported lower exposure to ACE and later contacts with mental health professionals than drug-treated. This effect was particularly evident in female patients compared to males. The interaction of gender with factors linked with the early familial environment biased access to psychiatric care and use of medication, independent of OCD-associated factors such as severity of symptoms or duration of illness. The need for medications of patients could be higher in families where OCD symptomatology is associated with ACE.Comprehensive psychiatry 10/2013; DOI:10.1016/j.comppsych.2013.08.028 · 2.26 Impact Factor