Hippocampal Subfield Volumes and Cognitive Function in Schizophrenia and Mood Disorders

<b><i>Introduction:</i></b> The hippocampus is relevant to cognitive function in schizophrenia (SCZ) and mood disorder patients. Although not anatomically uniform, it is clearly divided into subfields. This study aimed to elucidate the relationship between hippocampal subfield volume and cognitive function in patients with SCZ, bipolar disorder (BP), and major depressive disorder (MDD). <b><i>Methods:</i></b> The study included 21 patients with SCZ, 22 with BP, and 21 with MDD and 25 healthy controls (HCs). Neurocognitive function was assessed using the Brief Assessment of Cognition in Schizophrenia. We obtained hippocampal subfield volumes using FreeSurfer 6.0. We compared the volumes of the hippocampal subfield between the 4 groups and ascertained correlation between the cognitive composite score and hippocampal subfield volume in each group. <b><i>Results:</i></b> The SCZ group had significantly lower cognitive composite score than the BP, MDD, and HC groups. In the SCZ group, the left and right hippocampus-amygdala transition area and right subiculum and right presubiculum volumes were significantly reduced compared to those in the HC group. The left presubiculum volumes in the SCZ group were significantly reduced compared to those in the MDD group. Subfield volumes did not significantly differ between the BP, MDD, and HC groups. Interestingly, in the SCZ group, volumes of the right CA1, right molecular layer of the hippocampus, and right granule cell and molecular layer of the dentate gyrus were significantly correlated with the cognitive composite score. <b><i>Conclusion:</i></b> Patients with SCZ had poorer cognitive function, which is related to their hippocampal pathology, than those with mood disorders.

Elevated risk of mood disorders after the occurrence of recurrent retinal detachment: a population-based cohort study

Introduction: To investigate the risk of mood disorders in patients who experienced retinal detachment (RD) by using the National Health Insurance Research Database in Taiwan. Methods: Participants with a diagnosis of RD were regarded as the study group, and an age- and sex-matched group without a diagnosis of RD served as the control group. The outcomes related to mood disorders after RD included (1) psychiatric outpatient department visits; (2) behavioural therapy; (3) sleep or anxiety-related disorders; and (4) major depressive disorder (MDD). Results: A total of 4,129 participants diagnosed with RD and 16,516 non-RD individuals were enrolled in the study. There were no significant differences in the four mood disorder-related outcomes between the study and control groups. However, the patients with recurrent RD who received more than two treatments and female patients with RD who needed surgical treatment showed a higher probability of developing MDD than did the non-RD subjects (incidence rate: 0.96 versus 0.36; adjusted hazard ratio (aHR): 2.382, 95% CI: 1.032–5.496, log-rank P= 0.0325; and aHR: 6.895, 95% CI: 1.659–28.656, log-rank P= 0.0060, respectively). Conclusion: Patients with recurrent RD and multiple surgeries and females with RD who needed surgical treatment were at greater risk for developing MDD.

Sex differences in the alcohol-mediated modulation of BLA network states

About 85% of adults in the United States report drinking alcohol in their lifetime. Mood disorders, like generalized anxiety disorder and major depression, are highly comorbid with alcohol use. The basolateral amygdala (BLA) is an area of the brain that is heavily implicated in both mood disorders and alcohol use disorder. Importantly, modulation of BLA network/oscillatory states via parvalbumin-positive (PV) GABAergic interneurons has been shown to control the behavioral expression of fear and anxiety. Further, PV interneurons express a high density of δ-subunit-containing GABAA receptors (GABAARs), which are sensitive to low concentrations of alcohol. Our lab previously demonstrated that δ-subunit-containing GABAARs on PV interneurons in the BLA influence voluntary ethanol intake and anxiety-like behavior in withdrawal. Therefore, we hypothesized that the effects of alcohol may modulate BLA network states that have been associated with fear and anxiety behaviors via δ-GABAARs on PV interneurons in the BLA. Given the impact of ovarian hormones on the expression of δ-GABAARs, we examined the ability of alcohol to modulate local field potentials (LFPs) in the BLA from male and female C57BL/6J and Gabrd-/- mice after acute and repeated exposure to alcohol. Here, we demonstrate that acute and repeated alcohol can differentially modulate oscillatory states in male and female C57BL/6J mice, a process which involves δ-GABAARs. This is the first study to demonstrate that alcohol is capable of altering network states implicated in both anxiety and alcohol use disorders.

Latent subtypes of manic and/or irritable episode symptoms in two population-based cohorts

Background Mood disorders are characterised by pronounced symptom heterogeneity, which presents a substantial challenge both to clinical practice and research. Identification of subgroups of individuals with homogeneous symptom profiles that cut across current diagnostic categories could provide insights in to the transdiagnostic relevance of individual symptoms, which current categorical diagnostic systems cannot impart. Aims To identify groups of people with homogeneous clinical characteristics, using symptoms of manic and/or irritable mood, and explore differences between groups in diagnoses, functional outcomes and genetic liability. Method We used latent class analysis on eight binary self-reported symptoms of manic and irritable mood in the UK Biobank and PROTECT studies, to investigate how individuals formed latent subgroups. We tested associations between the latent classes and diagnoses of psychiatric disorders, sociodemographic characteristics and polygenic risk scores. Results Five latent classes were derived in UK Biobank (N = 42 183) and were replicated in the independent PROTECT cohort (N = 4445), including ‘minimally affected’, ‘inactive restless’, active restless’, ‘focused creative’ and ‘extensively affected’ individuals. These classes differed in disorder risk, polygenic risk score and functional outcomes. One class that experienced disruptive episodes of mostly irritable mood largely comprised cases of depression/anxiety, and a class of individuals with increased confidence/creativity reported comparatively lower disruptiveness and functional impairment. Conclusions Findings suggest that data-driven investigations of psychopathological symptoms that include sub-diagnostic threshold conditions can complement research of clinical diagnoses. Improved classification systems of psychopathology could investigate a weighted approach to symptoms, toward a more dimensional classification of mood disorders.