Can magnetic resonance imaging enhance the assessment of potential new treatments for cognitive impairment in mood disorders? A systematic review and position paper by the International Society for Bipolar Disorders Targeting Cognition Task Force.

BACKGROUND: Developing treatments for cognitive impairment is key to improving the functioning of people with mood disorders. Neuroimaging may assist in identifying brain-based efficacy markers. This systematic review and position paper by the International Society for Bipolar Disorders Targeting Cognition Task Force examines the evidence from neuroimaging studies of pro-cognitive interventions. METHODS: We included magnetic resonance imaging (MRI) studies of candidate interventions in people with mood disorders or healthy individuals, following the procedures of the Preferred Reporting Items for Systematic reviews and Meta-Analysis 2020 statement. Searches were conducted on PubMed/MEDLINE, PsycInfo, EMBASE, Cochrane Library, and Clinicaltrials.gov from inception to 30th April 2021. Two independent authors reviewed the studies using the National Heart, Lung, Blood Institutes of Health Quality Assessment Tool for Controlled Intervention Studies and the quality of neuroimaging methodology assessment checklist. RESULTS: We identified 26 studies (N = 702). Six investigated cognitive remediation or pharmacological treatments in mood disorders (N = 190). In healthy individuals, 14 studies investigated pharmacological interventions (N = 319), 2 cognitive training (N = 73) and 4 neuromodulatory treatments (N = 120). Methodologies were mostly rated as 'fair'. 77% of studies investigated effects with task-based fMRI. Findings varied but most consistently involved treatment-associated cognitive control network (CCN) activity increases with cognitive improvements, or CCN activity decreases with no cognitive change, and increased functional connectivity. In mood disorders, treatment-related default mode network suppression occurred. CONCLUSIONS: Modulation of CCN and DMN activity is a putative efficacy biomarker. Methodological recommendations are to pre-declare intended analyses and use task-based fMRI, paradigms probing the CCN, longitudinal assessments, mock scanning, and out-of-scanner tests.

A multinational study to pilot the modified Hypomania Checklist (mHCL) in the assessment of mixed depression.

BACKGROUND: Mixed depression is a common, dimensional phenomenon that is increasingly recognized in unipolar and bipolar disorders. We piloted a modified version of the Hypomania Checklist (mHCL-32) to assess the prevalence and clinical correlates of concurrent manic (hypo) symptoms in depressed patients. METHODS: The mHCL-32, Young Mania Rating Scale (YMRS) and Hamilton Rating Scale for Depression (HAMD-24) were utilized in the assessment of unipolar (UP=61) and bipolar (BP=44) patients with an index major depressive episode confirmed by the Structured Clinical Interview for DSM-IV (SCID). Differential mHLC-32 item endorsement was compared between UP and BP. Correlation analyses assessed the association of symptom dimensions measured by mHCL-32, YMRS and HAMD-24. RESULTS: There was no significant difference between mood groups in the mean mHCL-32 and YMRS scores. Individual mHLC-32 items of increased libido, quarrels, and caffeine intake were endorsed more in BP vs. UP patients. The mHCL-32 active-elevated subscale score was positively correlated with the YMRS in BP patients and negatively correlated with HAMD-24 in UP patients. Conversely, the mHCL-32 irritable-risk taking subscale score was positively correlated with HAMD-24 in BP and with YMRS in UP patients. LIMITATIONS: Small sample size and cross-sectional design. CONCLUSION: Modifying the HCL to screen for (hypo) manic symptoms in major depression may have utility in identifying mixed symptoms in both bipolar vs. unipolar depression. Further research is encouraged to quantify mixed symptoms with standardized assessments.