Bipolar Disorder and Epilepsy: Clinical and Neurobiological Overlaps, Evidence Gaps, and an Exploratory Systems Perspective.

backgroundAccumulating evidence suggests that bipolar disorder (BD) and epilepsy share important clinical, neurobiological, and therapeutic features. Both disorders are characterized by recurrent episodes and fluctuating clinical courses, raising the possibility that partially overlapping or analogous regulatory processes may contribute to some aspects of their clinical expression and progression. This review examines current evidence regarding the overlap between BD and epilepsy and explores integrative perspectives that may help explain their similarities.

methodsA narrative review of the literature was conducted. Evidence related to genetics, neuroimaging, cognition, neuroplasticity, neuroinflammation, stress biology, network neuroscience, and treatment response was examined.

resultsFindings across BD and epilepsy reveal partially overlapping biological and clinical features, including alterations in excitation-inhibition balance, neuromodulatory disturbances, neuroinflammatory processes, and neuroplastic changes. Neuroimaging studies in both conditions reveal abnormalities in large-scale brain networks involved in emotional regulation, cognitive control, and behavioral adaptation. Clinically, both disorders show sensitivity to environmental and physiological stressors and sleep disruption, cognitive impairment, and partial responsiveness to overlapping pharmacological and neuromodulatory interventions. These observations are compatible with the hypothesis that recurrent episodes and prolonged network dysregulation may reinforce maladaptive patterns of instability through interacting feedback processes, although this interpretation remains to be tested directly.

conclusionsCurrent evidence identifies several clinical and biological similarities between BD and epilepsy but does not yet establish that these similarities reflect identical or directly shared causal mechanisms. An integrative perspective combining network dysfunction, neuroplasticity, and systemic regulatory processes may provide a useful heuristic framework for investigating disease heterogeneity, progression, and treatment response. Further longitudinal and comparative studies are required before this perspective can support personalized monitoring strategies or mechanism-informed interventions.