Manic and hypomanic states in cancer patients: A systematic review

OBJECTIVES: While there have been reports on the relationship between cancer and depression, reports on the association between cancer and manic states, a reciprocal state of depression, have been relatively few. Therefore, we conducted a systematic review on the relationships between cancer and manic states, focusing on their etiology, clinical course, and impact on cancer treatments. METHODS: A systematic review was conducted using four electronic databases, following the PRISMA guidelines. The scope of the study included research on manic or hypomanic states associated with cancer in patients with no prior history of mental illness, published from 1950 to August, 2021. The study protocol was registered with PROSPERO (CRD42020182372). RESULTS: Fifty-six studies, including 67 cases, were identified. The etiology of manic states in cancer patients was classified into organic, drug-induced, and psychogenic, with steroids being the most predominant causative agent. Approximately half of the patients discontinued cancer treatment following the onset of manic states. This was associated with a low rate of pharmacological treatment during the acute and maintenance phase of mania. The onset of manic states was most frequent during cancer treatment; however, about 15% of the cases exhibit manic symptoms before cancer diagnosis. SIGNIFICANCE OF RESULTS: This systematic review illustrated the clinical characteristics of manic state regarding differences in the etiology, timing of onset, pharmacological treatments, duration to remission, recurrence, and impact on cancer treatment. Manic states, which are comorbid with cancer, have significant clinical impacts on cancer prognosis. Therefore, appropriate pharmacological treatment for manic states is critical to consolidate appropriate cancer treatment. A substantial proportion of patients exhibit manic symptoms prior to the diagnosis of cancer, warranting further investigation into the possibility of the concept of "premonitory mania."