What increases the risk of overdose?
- By Robert Mauer
- Reviewed by: Dr. Janaka Hanvey, PhD
Overdose risk increases with higher doses, high-potency substances, and combining drugs—especially when multiple central nervous system depressants (such as opioids, alcohol, or benzodiazepines) are used together. Unknown strength or contamination further increases risk by making dosing unpredictable.
Individual factors also matter. Low tolerance, underlying health conditions, and using alone increase the likelihood that an overdose becomes severe or fatal.
High-risk situations include changes in supply, mixing substances, and returning to use after a period of abstinence.
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National Institute on Drug Abuse (NIDA) — Drugs, Brains, and Behavior: The Science of Addiction
Government scientific overview of drug use, addiction, brain changes, tolerance, dependence, and recovery.
National Institute on Drug Abuse (NIDA) — Commonly Used Drugs Charts
Comprehensive federal reference covering major drug categories, effects, overdose risks, and health consequences.
Substance Abuse and Mental Health Services Administration (SAMHSA) — Substance Use and Mental Health
Federal information about substance use, addiction, prevention, treatment, and behavioral health.
MedlinePlus — Drugs and Young People
Government medical resource discussing drug effects, misuse, addiction risks, and substance use education.
National Institute on Drug Abuse (NIDA) — Understanding Drug Use and Addiction DrugFacts
Clear explanation of why people use drugs, how addiction develops, and how substance use affects the brain and behavior.