Objectives: To characterize lifetime psychiatric diagnosis groups among methadone maintenance treatment (MMT) patients and associations of diagnosis to long-term (up to 20 years) retention and survival either during treatment or post discontinuation.
Methods: A total of 758 patients with available psychiatric diagnosis (98% of those ever admitted between June 1993 and June 2012) were followed-up until June 2013. Lifetime psychiatric diagnosis was assessed according to DSM-IV-TR (Axis I, II, I & II, or none). Observed urine samples at 1 and 13 months were positive for drugs if at least one was positive. Survival data were based on the Israel National Population Registry. Survival and retention in MMT were compared (Kaplan Meier) between groups.
Results: The Axis II (personality disorders) group had the worst mean long-term retention (5.8 years, 95% Confidence Interval (CI) 5.0-6.5) compared with the Axis I, Axis I & II or no psychiatric diagnosis groups (9.6 years, 95% CI 8.8-10.4) (P < 0.0005). Mean survival since admission (16.4 years, 95% CI 15.9-16.9) was similar for all groups. Axis II patients included more males, more drug injectors, were younger at initial opiate use and more likely left treatment before 1 year.
Conclusions: Personality and coping mechanisms (Axis II) could be significant obstacles to the success of MMT, warranting special interventions to overcome them.
Keywords: methadone maintenance treatment; opioids; personality disorders; retention; survival.