These drugs have a stimulating effect and produce tolerance and psychological dependence. They produce a depressant and sedative effect as well as physical and psychological dependence. They have hallucinogenic properties and can produce psychological dependence. Acute drug intoxication and drug overdose may be accidental or intentional. Drug withdrawal symptoms can occur when use of a substance is stopped or reduced.
Withdrawal symptoms vary, depending on the abused substance.
The onset of withdrawal symptoms depends on the length of time the drug normally stays within the body. Opiate withdrawal starts between 6 to 12 hours after the last use. Drug intoxication, overdose, and withdrawal can be life-threatening situations. The incidence of drug abuse and dependence is widespread and affects all levels of society, causing a major public health problem. High blood pressure may also be associated with drug abuse .