Objectives: Magnetic resonance imaging (MRI) studies comparing bipolar and unipolar depression characterize pathophysiological differences between these conditions. However, it is difficult to interpret the current literature due to differences in MRI modalities, analysis methods, and study designs.
Methods:We conducted a systematic review of publications using MRI to compare individuals with bipolar and unipolar depression. We grouped studies according to MRI modality and task design. Within the discussion, we critically evaluated and summarized the functional MRI research and then further complemented these findings by reviewing the structural MRI literature.
Results:We identified 88 MRI publications comparing participants with bipolar depression and unipolar depressive disorder. Compared to individuals with unipolar depression, participants with bipolar disorder exhibited heightened function, increased within network connectivity, and reduced grey matter volume in salience and central executive network brain regions. Group differences in default mode network function were less consistent but more closely associated with depressive symptoms in participants with unipolar depression but distractibility in bipolar depression.
Conclusions:When comparing mood disorder groups, the neuroimaging evidence suggests that individuals with bipolar disorder are more influenced by emotional and sensory processing when responding to their environment. In contrast, depressive symptoms and neurofunctional response to emotional stimuli were more closely associated with reduced central executive function and less adaptive cognitive control of emotionally oriented brain regions in unipolar depression. Researchers now need to replicate and refine network-level trends in these heterogeneous mood disorders and further characterize MRI markers associated with early disease onset, progression, and recovery.
Background
When assessing the value of an intervention in bipolar disorder, researchers and clinicians often focus on metrics that quantify improvements to core diagnostic symptoms (e.g., mania). Providers often overlook or misunderstand the impact of treatment on life quality and function. We wanted to better characterize the shared experiences and obstacles of bipolar disorder within the United States from the patient’s perspective.
Methods
We recruited 24 individuals diagnosed with bipolar disorder and six caretakers supporting someone with the condition. Participants were involved in treatment or support services for bipolar disorder in central Texas. As part of this qualitative study, participants discussed their everyday successes and obstacles related to living with bipolar disorder during personalized, open-ended interviews. Audio files were transcribed, and Nvivo software processed an initial thematic analysis. We then categorized themes into bipolar disorder-related obstacles that limit the patient’s capability (i.e., function), comfort (i.e., relief from suffering) and calm (i.e., life disruption) (Liu et al., FebClin Orthop 475:315–317, 2017; Teisberg et al., MayAcad Med 95:682–685, 2020). We then discuss themes and suggest practical strategies that might improve the value of care for patients and their families.
Results
Issues regarding capability included the struggle to maintain identity, disruptions to meaningful employment, relationship loss and the unpredictable nature of bipolar disorder. Comfort related themes included the personal perception of diagnosis, social stigma and medication issues. Calm themes included managing dismissive doctors, finding the right psychotherapist and navigating financial burdens.
Conclusions
Qualitative data from patients with bipolar disorder helps identify gaps in care or practical limitations to treatment. When we listen to these individuals, it is clear that treatments must also address the unmet psychosocial impacts of the condition to improve patient care, capability and calm.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.