OBJECTIVES:To explore the distribution of TCM patterns in ketamine users and the inter-rater reliability ofTCM diagnosis amongTCM practitioners.METHODS:Eighty-four subjects recruited from substance abuse clinics and non-governmental counseling services catering for ketamine abusers were examined by one or two TCM practitioners.The distribution and inter-rater reliability of the TCM diagnoses between the two TCM practitioners were described and measured.RESULTS:Seven TCM patterns were differentiated.The four most common patterns were the Heart Yin deficiency(29.8%),Kidney Yang deficiency(26.2%),KidneyYin deficiency(19.0%),and SpleenYang defi-ciency(14.3%).The agreement between the two TCM practitioners was 59%;the kappa for the three most common patterns was 0.472(P=0.003).The proportion of men was lower in the KidneyYin deficiency group(18.8%),in comparison to the Heart Yin deficiency(60.0%,P=0.009) and KidneyYang deficiency group(59.1%,P=0.013).CONCLUSION:The differences between the TCM groups in terms of the source of referral and number of drug uses other than ketamine were of borderline significance.Further research should focus on validating diagnostic tools and improving inter-rater reliability in TCM to enhance the quality of clinical trials ofTCM treatments for ketamine abuse.