Caffeine consumption among eating disorder patients: epidemiology, motivations, and potential of abuse

OBJECTIVE: Aim of the study was to investigate caffeine use in different types of eating disorders (ED) patients either using a categorical approach [Diagnostic and Statistical Manual of Mental Disorders - Fourth Edition - Text Revision (DSM-IV-TR) diagnostic criteria] or a dimensional perspective. METHOD: Fifty-eight ED female patients [anorexia nervosa (AN), restricting and binge-eating/purging type, N=15; bulimia nervosa (BN) purging type/nonpurging type, N=26; binge eating disorder (BED), N=17] referred to an Eating Disorder Unit and 15 non-clinical controls were administered the Eating Disorder Inventory-2 (EDI-2), the Clinical Global Impression (CGI) and the Caffeine Use Test, an interview specifically developed to investigate caffeine intake. Statistical analyses were then repeated clustering patients according to the presence/absence of purging behaviors (purgers, N=22; non-purgers, N=19; BED, N=17). RESULTS: Current and lifetime caffeine use, measured as mg/day, were similar comparing controls and ED patients as a whole. BN patients showed a significantly higher maximum lifetime caffeine intake (817.4+/-528,9 vs 325.0+/-294.6 mg/die, F=3.246, p<0.05); the same for purgers vs controls (p<0.05). Caffeine abuse was significantly more represented among patients vs controls (p<0.01), but similar among different patients' groups. As for diagnoses according to DSM-IV-TR Substance Use modified for caffeine, no significant difference was found among the different groups, for either Dependence, Intoxication or Withdrawal. Most of patients and controls reported pleasure as the main motivation for caffeine use, followed by increased vigilance and attention and appetite suppression in AN and BN patients. Note that a shift in diagnosis in the course of the ED from non-purging to purging type was associated with an increase in caffeine current, lifetime and maximum lifetime intake (F=1.667 p<0.05), except for BED patients. Severity of the ED measured as CGI score or comorbidity did not affect caffeine intake in patients as a whole, but in the purging subgroup current caffeine use was increased in presence of an anxiety disorder (p<0.05), and decreased in presence of a mood disorder (p<0.01). CONCLUSIONS: Data from the present study are in agreement with previous evidence in literature that a high percentage of ED patients ordinarily use caffeine with an average intake similar to that of the general population, however with a kind of binge attitude. Among heavy drinkers, daily caffeine intake and alcohol/cigarettes use are associated supporting the link with the dimension of impulse disregulation. The substantial number of subjects from our sample satisfying research criteria for Dependence, together with increasing reports of caffeine intoxication, suggests the growing relevance of these issues that deserve further investigation.