CAFFEINE DEPENDENCE SYNDROME - EVIDENCE FROM CASE-HISTORIES AND EXPERIMENTAL EVALUATIONS

Objective.-The extent to which daily caffeine use is associated with a substance dependence syndrome similar to that associated with other p sychoactive drugs is unknown. The purpose of this study was to assess volunteers who reported problems with their use of caffeine for eviden ce suggesting a diagnosis of caffeine dependence based on the generic criteria for substance dependence from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Design.-Case-seri es evaluations. Setting.-An academic research center. Participants.-Se lf-identified adults who believed they were psychologically or physica lly dependent on caffeine. Main Outcome Measure.-Diagnoses made by a p sychiatrist using a structured clinical interview that included a sect ion on caffeine dependence based on generic criteria for DSM-IV substa nce dependence. Secondary Outcome Measure.-Double-blind caffeine-withd rawal evaluation. Results.-Ninety-nine subjects were screened for the study, and 16 were identified as having a diagnosis of caffeine depend ence. Median daily caffeine intake was 357 mg, and 19% of subjects con sumed less than the national (US) daily average of caffeine. Criteria used for making diagnoses (and rates of their prevalence) were as foll ows: withdrawal (94%), use continued despite knowledge of a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by caffeine use (94%), persistent desire o r unsuccessful efforts to cut down or control use (81%), and tolerance (75%). Eleven subjects underwent the double-blind caffeine-withdrawal evaluation portion of the study, and nine (82%) of the 11 showed obje ctive evidence of caffeine withdrawal, including eight of 11 with func tional impairment. Conclusions.-These results, together with other exp erimental evidence, suggest that caffeine exhibits the features of a t ypical psychoactive substance of dependence. It is valuable to recogni ze caffeine dependence as a clinical syndrome, since some people feel compelled to continue caffeine use despite desires and recommendations to the contrary.