Depression in Cancer Patients

Depression is one of the most common psychiatric complications in cancer patients, with prevalence rates ranging from 7.9% to 32.4%, significantly exceeding those in the general population. Psychological distress may arise at any stage of the cancer trajectory, from diagnosis to treatment and palliative care. While sadness, anxiety, and grief can represent normal emotional responses, persistent and functionally impairing symptoms may indicate major depressive disorder, adjustment disorder, or demoralization syndrome. Accurate diagnosis requires differentiation from cancer-related symptoms, treatment side effects, delirium, and other psychiatric comorbidities. Psychoneuroimmunological mechanisms, including proinflammatory cytokine activation, hypothalamic–pituitary–adrenal axis dysregulation, and impaired immune function, contribute to depression in cancer patients. Comorbid depression adversely affects quality of life, adherence to treatment, and survival outcomes, and significantly increases suicide risk. Screening with brief tools such as the Distress Thermometer is recommended, followed by comprehensive assessments (e.g., Hospital Anxiety and Depression Scale [HADS], Patient Health Questionnaire-9 [PHQ-9]). Effective management requires a biopsychosocial approach, combining pharmacologic treatments—such as selective serotonin reuptake inhibitor (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), or mirtazapine—with psychosocial interventions tailored to the patient’s disease stage and psychosocial context. Despite growing evidence, high-quality intervention studies remain limited, underscoring the need for integrated oncology and mental healthcare to optimize patient outcomes.