What is drug dependence relative to psychoactive substance toxicity, intoxication, and withdrawal symptoms for three identified drugs of abuse. 

Psychopharmacological effects of psychoactive substances

The compulsive use of substances, or substance use disorder as it is also called, can lead to drug dependence. When a substance is consumed in large quantities, it may cause physical and mental problems. This is often caused by overdosing. The state of intoxication can include slurred or distorted speech, confusion, impaired judgment and/or coordination, as well as changes in mood and/or behavior. Withdrawal symptoms occur when someone stops using a drug abruptly after developing dependence on it—this may include anxiety, insomnia, nausea, sweating or shaking. The specific withdrawal symptoms can vary according to the drug used. They may include anxiety, insomnia, nausea or agitation in cases of benzodiazepines or alcohol.