Double burden of cancer and bipolar disorder: Implications for mental health care

Table 1 Psychosocial and healthcare-related factors affecting cancer outcomes in patients with bipolar disorder

Domain	Key findings	Evidence	Impact on cancer outcomes	Clinical implications
Stigma	Severe mental illness patients less likely to receive screening	Observational studies	Delayed diagnosis, advanced stages	Need for proactive screening
Healthcare access	Reduced access to oncologic care	Population-based studies	Higher cancer mortality	Integrated care pathways
Diagnostic delay	Later-stage cancer diagnosis	Cohort studies	Poorer prognosis	Early referral strategies
Psychological distress	High rates of depression, anxiety	Clinical studies	Reduced treatment adherence	Routine psychiatric assessment
Psychosocial interventions	Cognitive behavioral therapy, supportive therapy effective	Randomized controlled trials in cancer populations	Improved quality of life and adherence	Adaptation for bipolar disorder needed
Care coordination	Multidisciplinary models beneficial	Integrated care studies	Improved continuity of care	Psychiatry-oncology collaboration

It provides an overview of major psychosocial and healthcare-related domains influencing cancer outcomes in patients with bipolar disorder and other severe mental illnesses. For each domain, key findings, type of supporting evidence, impact on cancer outcomes, and potential clinical implications are summarized. It emphasizes how stigma, reduced healthcare access, diagnostic delays, psychological distress, and inadequate care coordination can negatively affect cancer prognosis and treatment adherence, underscoring the need for proactive screening strategies and integrated psychiatry-oncology care models.

Table 2 Shared biological and treatment-related mechanisms linking bipolar disorder and cancer

Domain	Mechanism	Evidence in BD	Evidence in cancer	Clinical implications
Inflammation	Tumor necrosis factor alpha, interleukin-6 have increased	Acute episodes, early BD	Tumor progression, immune evasion	Mood destabilization, worse prognosis
Hypothalamic-pituitary-adrenal axis	Cortisol dysregulation	Flattened rhythm	Reduced survival	Stress vulnerability
Corticosteroids	Exogenous glucocorticoids	Mania induction	Supportive cancer care	High psychiatric risk
Genetics	Shared single nucleotide polymorphisms	Immune-related genes	Cancer susceptibility	Biological vulnerability
Lithium	Glycogen-synthase-kinase 3β inhibition	Mood stabilization	Anti-proliferative effects (preclinical)	Requires strict monitoring
Drug interactions	Cytochrome P450 modulation	Pharmacokinetic/pharmacodynamic alterations	Chemotherapy toxicity	Need interdisciplinary care

It summarizes the main biological and treatment-related domains that converge in bipolar disorder and cancer. For each domain, the underlying mechanism, evidence in bipolar disorder, evidence in cancer, and key clinical implications are reported. It highlights how chronic inflammation, hypothalamic-pituitary-adrenal axis dysregulation, corticosteroid exposure, shared genetic susceptibility, lithium-related molecular pathways, and pharmacokinetic and pharmacodynamic drug-drug interactions may jointly contribute to mood destabilization and adverse oncological outcomes, underscoring the need for interdisciplinary clinical management. BD: Bipolar disorder.

Table 3 Key psychotropic-oncologic drug interactions and monitoring recommendations

Psychotropic drug/class	Relevant oncologic context	Potential interaction or risk	Monitoring/management recommendation
Lithium	Platinum-based chemotherapy, dehydration from chemotherapy (vomiting, diarrhea)	Reduced renal clearance leading to lithium toxicity	Monitor serum lithium levels, renal function, and electrolytes during treatment cycles
Carbamazepine	Taxanes, vinca alkaloids, etoposide	Cytochrome P450 enzyme system (CYP3A4) induction may reduce plasma levels of chemotherapeutic agents	Consider alternative mood stabilizer or monitor oncologic drug efficacy
Valproate	Hepatically metabolized anticancer drugs	Altered hepatic metabolism and potential hematologic toxicity	Monitor liver function tests and blood counts
Antipsychotics (e.g., quetiapine, haloperidol)	QT-prolonging anticancer agents	Additive QT interval prolongation and arrhythmia risk	Baseline and follow-up electrocardiogram monitoring
Clozapine	Myelosuppressive chemotherapy	Additive risk of neutropenia/agranulocytosis	Frequent blood count monitoring and close psychiatry-oncology coordination
Corticosteroids (oncologic supportive therapy)	Steroid-containing chemotherapy regimens	Risk of steroid-induced mania or mood destabilization	Monitor for insomnia, irritability, and manic symptoms; adjust mood stabilizer if needed