Addiction rewires control, not just willpower
Twin studies put heritability of alcohol use disorder near half, with similar figures for other drugs. Diagnostic manuals prefer substance use disorder over the loaded word addiction, and only gambling fully counts as a behavioral addiction in DSM-5-TR.
Addiction is framed as a neuropsychological condition: a lasting urge to chase a quick psychological reward from a drug or behavior even when harm piles up. Repeated use remolds brain networks for reward, executive control, stress, and mood, which helps explain both the craving and the weakened brakes. Substance forms include alcohol, cannabis, amphetamines, cocaine, nicotine, and opioids. For behaviors, DSM-5-TR fully recognizes only gambling disorder and keeps internet gaming under study; ICD-11 also lists gaming disorder. Whether food patterns qualify remains contested—neither manual names a food addiction.
Risk splits roughly evenly between genes and environment. Heritability for alcohol use disorder sits around 50 percent in twin and adoption work, and the architecture is polygenic rather than one-gene. Adverse childhood experiences, chronic stress, peers, poverty, and easy supply raise odds; adolescence is a high-vulnerability window. Clinically, DSM-5-TR grades substance use disorder mild to severe and treats the severe end as synonymous with drug addiction, while ICD-11 separates harmful episodes, harmful patterns, and dependence. Core signs include impaired control, social fallout, risky continued use, and often tolerance or withdrawal.
Harms are concrete. Overdose can stop breathing with opioids and other sedatives; injecting brings HIV and hepatitis C risk; long-term alcohol can scar the liver and cognition; tobacco damages lungs. Psychiatric illness often travels with addiction, and guidance favors treating both together. A meta-analysis of 47 cohort studies estimated suicide rates among people with substance use disorders at roughly five times expected levels, with raised risk across several substances and a stronger signal in women, though study estimates varied widely. Prevention with the best support includes family skills work, school social-skills programs, and policies that limit availability and raise price. Care is usually chronic and relapse-aware, mixing medication where it exists with psychological and social support.
Source: Addiction
