Rebound effect, discontinuation, and withdrawal syndromes associated with drugs used in psychiatric and neurological disorders.

Sudden cessation of the drug can cause withdrawal syndrome, discontinuation syndrome, or rebound effect. The common feature of these phenomena is a quick onset, usually limited duration depending on the drug's half-life and remission after restarting the therapy. They are characterized by varying clusters of somatic, autonomic, and psychiatric symptoms. Originally withdrawal syndrome was described for drugs with addictive properties such as barbiturates or benzodiazepines. On the other hand sudden abrupt of antidepressants or antipsychotics may cause discontinuation symptoms including movement or sensory disturbances, sleep disturbances, and hyperarousal but generally of less severity comparing to withdrawal syndrome. The aforementioned syndromes are physiologically based on the predominance of cellular counter-regulations as an effect of the sudden abrupt of a regularly taken medication. Classically the pathogenesis of withdrawal syndrome, based on physical dependence, results in life-threatening, long-lasting manifestations such as, seizures and delirium, different from the treated disease. In turn, these symptoms are not typical for discontinuation syndrome which is not considered as serious and usually spontaneously resolving. In turn, the rebound effect is clinically characterized by the relapse of the disease symptoms that are controlled by medication, but of greater severity than those before treatment.In the current review, we describe withdrawal and discontinuation syndromes associated with selected drugs used in psychiatry and neurology, risk factors, and recommendations for diminishing syndrome occurrence. Knowledge of their pathogenesis and symptoms resulting from drug discontinuation may be helpful in syndrome management and expectantly reduces the risk of diagnostic and therapeutic errors.