Hippocampal subfield volumes in mood disorders.

Volume reduction and shape abnormality of the hippocampus have been associated with mood disorders. However, the hippocampus is not a uniform structure and consists of several subfields, such as the cornu ammonis (CA) subfields CA1-4, the dentate gyrus (DG) including a granule cell layer (GCL) and a molecular layer (ML) that continuously crosses adjacent subiculum (Sub) and CA fields. It is known that cellular and molecular mechanisms associated with mood disorders may be localized to specific hippocampal subfields. Thus, it is necessary to investigate the link between the in vivo hippocampal subfield volumes and specific mood disorders, such as bipolar disorder (BD) and major depressive disorder (MDD). In the present study, we used a state-of-the-art hippocampal segmentation approach, and we found that patients with BD had reduced volumes of hippocampal subfields, specifically in the left CA4, GCL, ML and both sides of the hippocampal tail, compared with healthy subjects and patients with MDD. The volume reduction was especially severe in patients with bipolar I disorder (BD-I). We also demonstrated that hippocampal subfield volume reduction was associated with the progression of the illness. For patients with BD-I, the volumes of the right CA1, ML and Sub decreased as the illness duration increased, and the volumes of both sides of the CA2/3, CA4 and hippocampal tail had negative correlations with the number of manic episodes. These results indicated that among the mood disorders the hippocampal subfields were more affected in BD-I compared with BD-II and MDD, and manic episodes had focused progressive effect on the CA2/3 and CA4 and hippocampal tail.

Identifying neuroanatomical signatures of anorexia nervosa: a multivariate machine learning approach.

BACKGROUND: There are currently no neuroanatomical biomarkers of anorexia nervosa (AN) available to make clinical inferences at an individual subject level. We present results of a multivariate machine learning (ML) approach utilizing structural neuroanatomical scan data to differentiate AN patients from matched healthy controls at an individual subject level. METHOD: Structural neuroimaging scans were acquired from 15 female patients with AN (age = 20, s.d. = 4 years) and 15 demographically matched female controls (age = 22, s.d. = 3 years). Neuroanatomical volumes were extracted using the FreeSurfer software and input into the Least Absolute Shrinkage and Selection Operator (LASSO) multivariate ML algorithm. LASSO was 'trained' to identify 'novel' individual subjects as either AN patients or healthy controls. Furthermore, the model estimated the probability that an individual subject belonged to the AN group based on an individual scan. RESULTS: The model correctly predicted 25 out of 30 subjects, translating into 83.3% accuracy (sensitivity 86.7%, specificity 80.0%) (p < 0.001; χ 2 test). Six neuroanatomical regions (cerebellum white matter, choroid plexus, putamen, accumbens, the diencephalon and the third ventricle) were found to be relevant in distinguishing individual AN patients from healthy controls. The predicted probabilities showed a linear relationship with drive for thinness clinical scores (r = 0.52, p < 0.005) and with body mass index (BMI) (r = -0.45, p = 0.01). CONCLUSIONS: The model achieved a good predictive accuracy and drive for thinness showed a strong neuroanatomical signature. These results indicate that neuroimaging scans coupled with ML techniques have the potential to provide information at an individual subject level that might be relevant to clinical outcomes.

Changes in the corpus callosum in women with late-stage bipolar disorder.

OBJECTIVE: This study investigated the differences in corpus callosum (CC) volumes between women with early-stage and late-stage bipolar I (BP I) disorder using the criteria previously described in the literature. METHOD: We compared women with early- and late-stage BP I using criteria described in the Staging Systems Task Force Report of the International Society for Bipolar Disorders. We included 20 patients with early stage and 21 patients with late-stage BP I and a group of 25 healthy controls. Patients and controls underwent structural magnetic resonance imaging. Information on the clinical features of bipolar disorder was collected using a standardized questionnaire. Anatomical volumes of five regions of CC were compared between the three groups. RESULTS: Women with late-stage BP I disorder had reduced posterior CC volumes compared with early-stage bipolar I patients and controls (F = 6.05; P = 0.004). The difference was significant after controlling for age, comorbidity with post-traumatic stress disorder, psychotic symptoms during mood episodes, and current use of medication. CONCLUSION: The posterior CC was significantly decreased in volume in women with late-stage bipolar disorder. These findings suggest that CC may be an anatomical target of neuroprogression in the course of bipolar disorder in women.

Illness-course modulates suicidality-related prefrontal gray matter reduction in women with bipolar disorder.

OBJECTIVE: Explore interrelationships between suicide attempt history (Objective 1) or suicide attempt severity (Objective 2) with prefrontal cortex gray matter (PFCGM ) volume and illness-course in patients with bipolar disorder (BD). METHOD: Ninety-three women with BD-I or -II diagnosis (51 with and 42 without suicide attempt history) underwent structural MRI and filled out questionnaires. Measured were GM volumes of 11 PFC regions, BD illness-course, and attempt history and severity. Effects were examined with repeated measures GLM or logit analyses. RESULTS: Objective 1: Attempt history was associated with increased trait impulsivity and aggression, and higher prevalence of BD-I, past drug use disorder, and past psychiatric hospitalization. PFCGM volume was lower in patients with than without attempt history in those with past psychiatric hospitalization. PFCGM volume was higher in patients with than without attempt history in those without hospitalization. Higher trait aggression predicted attempt history. Objective 2: Increased frontal pole volume and younger age at first hospitalization predicted many suicide attempts. CONCLUSION: Attempt history in patients with BD related to PFCGM volume reduction or increase. Volume modulation by psychiatric hospitalization could reflect effects of illness-course or care. Attempt severity was not related to volume reduction. Research on suicidality-brain relationships should include illness-course and attempt severity measures.