Psychopharmacological effects of psychoactive substances
Drug dependence, also known as substance use disorder, involves the compulsive and continued use of drugs despite negative consequences. Psychoactive substance toxicity occurs when a drug is taken in such large amounts that it can cause serious physical or mental health issues; this is usually caused by an overdose. Intoxication is a state of being under the influence of drugs and can be characterized by changes in behavior and/or mood, slurred speech, confusion, impaired coordination and/or judgment, among other symptoms. Withdrawal symptoms occur when someone stops using a drug abruptly after developing dependence on it—this may include anxiety, insomnia, nausea, sweating or shaking. Specific withdrawal symptoms vary depending on the type of drug abused but may include restlessness for cocaine or opioids; irritability for marijuana; agitation for benzodiazepines; fever or muscle aches for alcohol and opiates; nausea vomitting for cannabis; seizure activity from stimulants such as methamphetamine or cocaine.