Intoxication

Intoxication is a physiologic state resulting from exposure to a substance or toxin that impairs mental function, perception, behavior, or motor coordination. It can be caused by alcohol, drugs, prescription medications, or environmental toxins and is distinguished from withdrawal, dependence, or chronic poisoning.

Effects depend on the substance, dose, and individual factors. Common features include altered mood or judgment, impaired attention, slowed reflexes, slurred speech, ataxia, nausea, and sometimes confusion or unconsciousness. Some intoxications produce stimulatory signs, others depressant effects.

Alcohol is the most common cause of intoxication worldwide. Other substances include cannabis, stimulants (eg, cocaine, methamphetamine), opioids, benzodiazepines, hallucinogens, and inhalants. Each substance has a characteristic syndrome (eg, alcohol intoxication with ataxia; opioid intoxication with sedation and constricted pupils).

Diagnosis is clinical, often supported by toxicology testing in hospital or forensic settings. Treatment emphasizes safety and supportive care: monitoring of vital signs, airway protection if needed, hydration, and gradual recovery. Specific antidotes or interventions may be used for certain substances, such as naloxone for opioid overdose or benzodiazepines for severe agitation.

Prevention and public health efforts aim to reduce harm from intoxication, including driver impairment laws, education, and screening for substance use. Intoxication differs from poisoning due to non-substance causes or from delirium associated with medical illness.