Aims To explore the rationale for claiming that benzodiazepines cause dependence while selective serotonin re-uptake inhibitors (SSRIs) do not.
Methods We analysed the definitions of dependence and withdrawal reactions as they had appeared over time in the Diagnostic Statistical Manual of Mental Diseases (DSM) and the International Classification of Diseases (ICD). We also compared the discontinuation symptoms described for the two drug groups in a systematic review.
Results The definition of substance dependence has changed over time in both the DSM and ICD. In the most recent classifications several criteria, including behavioural, physiological and cognitive manifestations, must be fulfilled. This change was published with the revision of the DSM-III revision in 1987 (DSM-IIIR), after the recognition of benzodiazepine dependence and just before the SSRIs were marketed in 1987–88. We found that discontinuation symptoms were described with similar terms for benzodiazepines and SSRIs and were very similar for 37 of 42 identified symptoms described as withdrawal reactions.
Conclusions Withdrawal reactions to selective serotonin re-uptake inhibitors appear to be similar to those for benzodiazepines; referring to these reactions as part of a dependence syndrome in the case of benzodiazepines, but not selective serotonin re-uptake inhibitors, does not seem rational.