Integration of neural and epigenetic contributions to posttraumatic stress symptoms: The role of hippocampal volume and glucocorticoid receptor gene methylation.

Many Veterans exposed to physical and psychological trauma experience symptoms of posttraumatic stress disorder (PTSD). As the etiology of PTSD symptoms is complex, a better understanding of the underlying biological mechanisms may improve preventative care and treatment for PTSD. Recent findings from the fields of neuroimaging and epigenetics offer important insights into the potential brain structures and biochemical pathways of modified gene expression associated with PTSD. We combined neuroimaging and epigenetic measures to assess current PTSD symptoms by measuring overall hippocampal volume and methylation of the glucocorticoid receptor (GR) gene (promoter region). Multiple regression analyses indicated that the hippocampal volume/GR methylation interaction was a predictor of PTSD symptoms. Our findings suggest that neuroimaging and epigenetic measures contribute interactively to PTSD symptoms. Incorporation of these metrics may aid in the identification and treatment of PTSD patients.

Plasma oxytocin concentrations and OXTR polymorphisms predict social impairments in children with and without autism spectrum disorder.

The neuropeptide oxytocin (OXT) and its receptor (OXTR) regulate social functioning in animals and humans. Initial clinical research suggests that dysregulated plasma OXT concentrations and/or OXTR SNPs may be biomarkers of social impairments in autism spectrum disorder (ASD). We do not know, however, whether OXT dysregulation is unique to ASD or whether OXT biology influences social functioning more generally, thus contributing to, but not causing, ASD phenotypes. To distinguish between these possibilities, we tested in a child ASD cohort, which included unaffected siblings and unrelated neurotypical controls (ages 3-12 y; n = 193), whether plasma OXT concentrations and OXTR SNPs (i) interact to produce ASD phenotypes, (ii) exert differential phenotypic effects in ASD vs. non-ASD children, or (iii) have similar phenotypic effects independent of disease status. In the largest cohort tested to date, we found no evidence to support the OXT deficit hypothesis of ASD. Rather, OXT concentrations strongly and positively predicted theory of mind and social communication performance in all groups. Furthermore, OXT concentrations showed significant heritability between ASD-discordant siblings (h(2) = 85.5%); a heritability estimate on par with that of height in humans. Finally, carriers of the "G" allele of rs53576 showed impaired affect recognition performance and carriers of the "A" allele of rs2254298 exhibited greater global social impairments in all groups. These findings indicate that OXT biology is not uniquely associated with ASD, but instead exerts independent, additive, and highly heritable influences on individual differences in human social functioning, including the severe social impairments which characterize ASD.

Validity of the 32-item Hypomania Checklist (HCL-32) in a clinical sample with mood disorders in China.

BACKGROUND: The 32-item Hypomania Checklist (HCL-32), a questionnaire for screening bipolar disorders, has been utilised in several countries, but it unclear if the Chinese version of the HCL-32 is valid. METHODS: Consecutive patients with bipolar disorders (BP, N = 300) and unipolar major depression (UP, N = 156) completed the Chinese version of the HCL-32. The subjects underwent a structured clinical interview for DSM-IV Axis-I disorders (SCID). RESULTS: The eigenvalues for the first three factors in the HCL-32 were calculated as 5.16 (active/elated), 2.72 (risk-taking) and 2.48 (irritable) using factor analysis. Cronbach's alpha for the HCL-32 was calculated to be 0.88. Positive responses to twenty-eight items were significantly more frequent by patients with BP than those with UP, and the other four items (7th, 21st, 25th and 32nd) showed no such trend. Fourteen was the optimal cut-off for discriminating between BP and UP. The HCL-32 distinguished between BP-II and UP, with 13 being the optimal cut-off. A cut-off of 13 yielded a sensitivity of 0.77 and a specificity of 0.62 between BP and UP. CONCLUSIONS: This study demonstrated that the simplified Chinese version of HCL-32 was valid for patients with mood disorders. The optimal cut-off of 13 for distinguishing between BP-II and UP was valid and could be used to improve the sensitivity of screening BP-II patients when the HCL-32 is used in psychiatric settings in China.

Validity of the Chinese version Mood Disorder Questionnaire (MDQ) and the optimal cutoff screening bipolar disorders.

To investigate the validity of the Chinese version of Mood Disorder Questionnaire (C-MDQ) in China. Patients with bipolar disorders (BP, N=284) and patients with unipolar depressive disorder (UP, N=134) were assessed with the C-MDQ. The Eigenvalues of the first two factors were 3.15 and 2.09, respectively. The Cronbach's alpha of the C-MDQ was 0.79. The frequency of positive responses of UP patients was significantly lower than those of BP patients for 12 items except the seventh item. A C-MDQ screening score of seven or more was the best cutoff between BP and UP. The C-MDQ could distinguish between bipolar II disorder (BP-II) and UP, and the best cutoff was five. A cutoff of five had a sensitivity of 0.80 and a specificity of 0.54 between BP and UP. This study demonstrated the good validity of C-MDQ in China. The best cutoff between BP-II and UP can be regarded as the optimal cutoff between BP and UP to improve the sensitivity of screening for BP-II. Five should be the optimal cutoff between the BP and UP when only the 13 items of the questionnaire are used in China.

COMT genotype, gender and cognition in community-dwelling, older adults.

A common polymorphism (Val158Met) in the gene encoding for the catechol-O-methyltransferase (COMT) enzyme has been associated with differences in prefrontal cognitive function in schizophrenic patients and healthy adults. While several studies indicate that the Met allele is associated with better performance on measures of executive function, working memory and verbal fluency, results have been inconsistent. Furthermore, fewer studies have investigated this relationship in older adults, a group known to experience impairments in prefrontal cognitive functions. Additionally, findings vary according to the gender distribution of study participants. We examined whether COMT genotype interacted with gender to impact cognition in a cohort of 163 healthy, older adults. Memory, verbal ability and areas of prefrontal cognitive function, including attention, speed-of-processing, and executive function, were assessed. We found no significant association between COMT genotype and any cognitive measure. However, gender interacted with COMT genotype to impact cognitive performance. Males homozygous for the Val allele performed better than both the Val/Met and Met/Met groups on measures of delayed recall. Heterozygous women performed better than their homozygous counterparts on the measure of verbal ability. These findings suggest that gender may be an important variable in consideration of the impact of COMT on cognition. Further, when gender is taken into consideration, any negative impact of COMT genotype may extend to cognitive domains other than those associated with prefrontal regions.