Root Causes of Substance Use Disorder: Biological, Psychological, and Social Factors

Substance use disorder (SUD) arises from a complex interplay of factors. No single cause; risk is cumulative.

Biological

• Genetics: Heritability 40–60% (twin studies). Variants in DRD2, OPRM1, COMT, ALDH2.
• Neurobiology: Dopamine reward pathway dysregulation; impaired prefrontal executive control.
• Comorbid mental illness: Depression, anxiety, PTSD, bipolar, ADHD → self-medication.

Psychological

• Trauma/ACEs (Adverse Childhood Experiences).
• Maladaptive coping (avoidance, emotional dysregulation).
• Impulsivity, sensation-seeking temperament.
• Low self-efficacy, hopelessness.

Social/Environmental

• Family: Parental SUD, poor supervision, conflict, neglect.
• Peers: Deviant peer group, social norms favoring use.
• Community: Poverty, violence, availability, marketing, weak enforcement.
• Cultural: Ritual use, stigma reducing help-seeking.

Developmental Trajectory

Experimentation → regular use → risky use → disorder. Early initiation (<15) increases SUD risk 4–5×.

Prevention/Treatment Implications

• Address ACEs, mental health, family functioning.
• Delay onset (evidence-based school/family programs).
• Medications (MOUD for OUD, naltrexone/acamprosate for AUD).
• CBT, MI, contingency management, 12-step.
• Recovery capital: housing, employment, community.

SUD is a chronic, treatable brain disorder—not a moral failing.