Depression: Causes, Risk Factors, and What You Need to Know

Depression (major depressive disorder) is a complex, multifactorial medical condition—not a character flaw. Contributing factors include:

Biological

• Genetics: Heritability ~40–50%; multiple genes interact with environment.
• Neurochemistry: Dysregulation of serotonin, norepinephrine, dopamine, glutamate, and GABA systems.
• Neuroendocrine: HPA axis hyperactivity, elevated cortisol.
• Neuroplasticity: Reduced BDNF, hippocampal atrophy.
• Inflammation: Elevated cytokines (IL-6, TNF-α) in subsets.

Psychological & Environmental

• Early adversity: Trauma, neglect, abuse.
• Stressful life events: Loss, divorce, job loss, financial strain.
• Personality traits: Neuroticism, low self-esteem, pessimism, rumination.
• Cognitive patterns: Negative attributional style, hopelessness.

Medical & Lifestyle

• Chronic illness (thyroid, cardiovascular, cancer, chronic pain)
• Medication side effects (beta-blockers, corticosteroids, hormonal)
• Substance use (alcohol, opioids, stimulants)
• Sleep disturbances, poor diet, sedentary lifestyle

Key Message

Depression is treatable. Effective options include psychotherapy (CBT, IPT), antidepressants, neuromodulation (TMS, ECT), and lifestyle modification. Early intervention improves prognosis. Seek professional help if symptoms persist >2 weeks.