Cannabis use in psychiatry inpatients.

Abstract

Background: Cannabis among patients admitted in psychiatric units is higher than the general population and this has been shown in various countries where studies on cannabis use have been undertaken. Such an observation has been made by psychiatrists in South Africa and the association between cannabis use and psychotic presentation among these patients has also been observed. Cannabis use by patients with severe or chronic medical illnesses to ameliorate the symptoms of such illnesses has been documented in the literature. A study to explore use of cannabis among psychiatric inpatients as well as medical patients was undertaken. Purpose: The purpose of this study was to firstly determine the prevalence of cannabis use in psychiatric patients admitted to an acute admissions unit in King Edward VIII Hospital and to correlate it with the psychiatric diagnosis. Secondly, it was to compare the cannabis use in psychiatric patients admitted to an acute admissions unit to patients admitted in a medical ward at King Edward VIII Hospital. Thirdly, to assess self reporting of cannabis use by psychiatric and medical patients. Methods: A case control study was conducted at King Edward VIII Hospital, Durban, where cannabis use among 64 subjects included in the study admitted in a psychiatric ward was compared with a control group of 63 control subjects admitted in a medical ward. Both groups were tested for urinary cannabinoids and a questionnaire was filled. The questionnaire contained demographic details as well as a question on use of substances including cannabis. Results: 17 subjects (26.6%) in the study group tested positive for urinary cannabinoids and 2 subjects (3.2%) in the control group tested positive. Cannabis use was significantly higher among males when compared to females in both the study group and the control group. Only 7 subjects in the study group reported cannabis use and out of those 7 subjects, 4 subjects tested positive for urinary cannabinoids. The commonest diagnosis among the study group subjects were the psychotic disorders and schizophrenia being the most common psychotic disorder. Conclusion: Cannabis use is significantly higher among psychiatric patients as compared to medical patients and it is probably higher than in the general population. Self reporting of cannabis use among psychiatric patients is low and unreliable and psychiatrists treating these patients must continue to use objective measures such as objective testing as well as collateral information to determine such use. In this study most subjects who tested positive for urine cannabis were likely to have a psychotic disorder and tended to be of younger age groups. The low prevalence of cannabis use in the control group makes it unlikely that there was a significant number of subjects in this group who were using cannabis for medicinal purposes.