Abstract
Objectives: Our aim was to estimate the prevalence of co-morbid psychiatric illness in persons with opiate dependence living in a regional city, who presented to the methadone program for maintenance therapy.
Methods: Each person who was accepted for methadone maintenance therapy between April and September 1999 was invited to take part in the study. A trained interviewer administered the Composite International Diagnostic Interview (CIDI) to participants and questioning was restricted to symptoms in the previous 12 months. All participants were invited to repeat the interview 1 to 3 months after commencing methadone maintenance.
Results: Of the 62 subjects (44 males, median age – 24 years) who agreed to participate in the study, 25 (40.3%) fulfilled DSM-IV diagnostic criteria for a Major Depressive Disorder, 22 (35.5%) for a Generalized Anxiety Disorder, 13 (20.9%) for a Panic Disorder, 13 (20.9%) for Post Traumatic Stress Disorder, 13 (20.9%) for Specific Phobias and 10 (16.1%) for Social Phobia. Only 15 (24.2%) did not fulfil criteria for at least one mental illness as well as their substance abuse disorder. There was no significant difference between the number of psychiatric disorders at the time of initial interview and at second interview in those who had a repeat interview 1 to 3 months after commencing methadone maintenance.
Discussion: Previous studies in Australia and in the U.S. have shown higher rates of co-existing psychiatric disorders in patients in or about to enter treatment for opioid dependence than for those with other drug use disorders. These results are comparable to previously published results for this population. The co-existence of substance use and mental illness has received increasing attention in national and international literature over the past decade. This study further highlights the need for a coordinated approach to those with dual diagnosis by both drug treatment and mental health services.