Psychiatric Morbidity in Ketamine Users Attending Counselling and Youth Outreach Services

ABSTRACT

Background: No study has examined ketamine users’ psychiatric morbidity using structured diagnostic instruments. The aim of this study was thus to determine the psychiatric comorbidity of community-based ketamine users using the Structured Clinical Interview for DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition), Axis I Disorders (SCID). Methods: A convenience sample of 200 frequent ketamine users was recruited from community organizations in Hong Kong. Participants were screened with the Severity of Dependence Scale (SDS), Beck Depression Inventory (BDI), Anxiety subscale of the Hospital Anxiety Depression Scale (HADSA), and SCID psychotic symptoms. Those who scored above the threshold (cutoff point of 8/9 on the BDI and 4/5 on HADSA) or displayed evidence of psychotic symptoms were referred for a structured clinical interview conducted by a psychiatrist. Results: One hundred and seventy participants scored above the cutoff point on 1 or more of the scales, and 115 participants attended the SCID interview. Fifty-one of these 115 participants received a psychiatric diagnosis of 1 or more comorbidities for the month preceding the interview. Mood disorders accounted for 80.4% of the diagnoses, anxiety disorders for 33.3%, and psychotic disorders for 7.8%. Conclusions: Female gender and history of psychiatric/psychological clinic attendance were significantly associated with comorbid psychiatric disorders, whereas ketamine dependence had a borderline association.

Keywords:

• Depression
• ketamine
• psychiatric comorbidity
• psychotic disorders
• substance use disorder

FUNDING

This study was supported by a grant from the Beat Drug Fund of Hong Kong (BDF 090066). The funding agency was not involved in the work reported in the manuscript or in the composition of the submission.

AUTHOR CONTRIBUTIONS

Author W. K. Tang designed the study and wrote the protocol and was the primary researcher and main author for the manuscript. Authors G. C. Lau and H. J. Liang managed the literature searches and summaries of previous related work, undertook the statistical analysis, and wrote the first draft of the manuscript. Author Alan Tang helped collect the data and gave valuable suggestions about the protocol and draft. Authors Celia Morgan and Gabor S. Ungvari rewrote the manuscript and gave critical comments. All authors contributed to and have approved the final manuscript.