Benzodiazepines are classified as anxiolytics or hypnotics, but the term “sedative” describes a group of drugs, including barbiturates and tricyclic antidepressants as well as benzodiazepines, which are abused. These drugs have different pharmacokinetic characteristics. Patients prescribed benzodiazepines seldom escalate their doses, and primary benzodiazepine abuse is rare. However, secondary abuse of all sedative drugs is common, and high doses are frequently consumed by patients dependent on opiates or alcohol to enhance the effects and by stimulant users to alleviate offset effects after a binge. Benzodiazepines cause dependence on prescribed doses with a clear withdrawal syndrome lasting a few weeks evident in 20–30% patients. The consumption of high doses can result in more severe withdrawal symptoms. Benzodiazepines should never be withdrawn abruptly because of the risk of fits or paranoid psychosis. A stepped care approach to reduction is recommended. All sedative drugs have characteristic pharmacodynamic effects, causing sedation, psychomotor slowing and memory impairment. They increase the risk of accidents and injuries and contribute to specific drug-related harms in abusers. Tolerance develops to some effects but long-term users are impaired compared with non-users. However, gradually stopping the drugs, even after several years of use, results in improvement in functioning, and there is no evidence of lasting impairment or cognitive decline. Newer anxiolytics and SSRIs appear to cause less impairment and have lower abuse potential.