What are the major categories of substances commonly abused, and what are their physiological effects on the body?

The major categories of substances commonly abused include stimulants, depressants, opioids, hallucinogens, and cannabis. Each category has distinct physiological effects on the body. Stimulants, such as cocaine and amphetamines, increase brain activity and energy levels. They elevate heart rate and blood pressure, leading to increased alertness, euphoria, and heightened energy. Prolonged use can result in cardiovascular problems, seizures, and psychological dependence. Depressants, including alcohol, benzodiazepines, and barbiturates, slow down brain activity and produce a calming effect. They can induce relaxation, sedation, and feelings of euphoria. However, excessive use can lead to respiratory depression, impaired coordination....