Drugs of Abuse (Forensic Toxicology)

Key points

• • Drugs of abuse are taken for their pleasurable or mind-altering effects, and they are broadly grouped by their action into depressants, stimulants and hallucinogens, though many do not fit neatly into one group.
• • Depressants such as opioids and alcohol slow the body down; an opioid overdose classically causes pinpoint pupils, slow shallow breathing and coma.
• • Stimulants such as cocaine and amphetamines speed the body up, causing wide pupils, a fast heart, high blood pressure, agitation and sometimes fatal heart rhythms.
• • Cannabis causes relaxation, red eyes, increased appetite and altered perception, and it is one of the most widely used illicit drugs.
• • Repeated use can lead to tolerance and dependence, and stopping a drug on which the body has become dependent causes a withdrawal reaction.
• • In forensic work, drugs and their breakdown products are detected in blood, urine and hair to help establish intoxication and the cause of death, though the exact time of use usually cannot be determined precisely.