SEROTONIN REUPTAKE INHIBITOR DISCONTINUATION SYNDROME - A HYPOTHETICAL DEFINITION

Adverse events following discontinuation from serotonin reuptake inhib itors (SRIs) are being reported in the literature with increasing freq uency; the frequency and severity of these symptoms appear to vary acc ording to the half-life of the SRI, e.g., the incidence appears higher with the shorter half-life agents than with fluoxetine, which has an extended half-life. Yet, there have been no systematic studies of the phenomenon to date. Therefore, a group of experts convened in Phoenix, Arizona, to develop a clear description or definition of the phenomen on based on these reports. The SRI discontinuation syndrome, referred to as ''withdrawal symptoms'' in many anecdotal case reports, is disti nctly different from the classic withdrawal syndrome associated with a lcohol and barbiturates. Antidepressants are not associated with depen dence or drug-seeking behavior. SRI discontinuation symptoms tend to b e short-lived and self-limiting, but can be troublesome. They may emer ge when an SRI is abruptly discontinued, when doses are missed, and le ss frequently, during dosage reduction. In addition, the symptoms are not attributable to any other cause and can be reversed when the origi nal agent is reinstituted, or one that is pharmacologically similar is substituted. SRI discontinuation symptoms, in most cases, may be mini mized by slowly tapering antidepressant therapy, but there have been s everal case reports where symptoms occurred consistently even through repeated attempts to taper therapy. Physical symptoms include problems with balance, gastrointestinal and flu-like symptoms, and sensory and sleep disturbances. Psychological symptoms include anxiety and/or agi tation, crying spells, and irritability. Further analyses of data base s and clinical studies are needed to define this proposed syndrome mor e clearly.