Overview: a comparison of withdrawal symptoms from different drug classes.

Whereas early formulations of addictive behaviour placed great emphasis upon withdrawal as a defining feature, current views focus more upon compulsive use as its central characteristic. However, the withdrawal syndrome continues to occupy an important place in the study of the addictions. It is interesting both in its own right and in relation to the development and maintenance of the compulsive use of drugs. Despite the attention devoted to withdrawal phenomena over many years, precise demarcation of the withdrawal symptoms associated with drugs of dependence has proved difficult to achieve. Withdrawal from all drugs of dependence appears to lead to mood disturbances although the extent to which these are due to the pharmacological actions of the drugs or to other physiological or psychological processes is unclear. Sleep disturbance is also common, although again direct links with the pharmacological actions of the withdrawn drug are yet to be established. Withdrawal from alcohol, benzodiazepines and opiates is often associated with somatic symptoms. In the former two cases, these can involve sweating, tremor and occasionally seizures. Perceptual disturbances have also been reported. In the case of opiates, flu-like symptoms are often reported, including muscle aches and gastric disturbances. In the case of nicotine, heightened irritability has been established as a direct pharmacological withdrawal effect. Characterization of stimulant withdrawal is still uncertain. There is little evidence of somatic symptoms but depression may occur as a result of a physiological rebound. There is also uncertainty over what role pharmacological withdrawal symptoms play in maintaining compulsive use.(ABSTRACT TRUNCATED AT 250 WORDS)