Background: Persons with polysubstance use problems are at high suicide risk, which may complicate substance use treatment. The purpose of this study was to a) examine cross-sectional and longitudinal risk factors for suicidality among persons in methadone maintenance treatment who present with co-occurring cocaine use disorder and b) evaluate whether suicidality impacts substance use outcomes independently and differentially depending on treatment type (i.e. standard methadone care [SC] vs. contingency management plus standard care [CM + SC]).
Methods: Data come from five randomized controlled trials of CM conducted within methadone clinics (N = 562). Participants were categorized (mutually exclusive) as no history of suicidality (56.4%, n=317), past suicidal ideation (SI; 11%, n=62), recent SI (3.6%, n=20), or lifetime suicide attempt (29%, n=163).
Results: Suicidality groups differed by sex and baseline employment, income, trauma history, and psychosocial functioning. Suicide attempt history was positively associated with years of polysubstance use, prior drug treatments, and unintentional overdose history. Baseline psychological problem severity and emotional abuse history were associated with SI likelihood 12 weeks later. Past SI was associated with longer durations of abstinence than no suicidality. Unexpectedly, those with recent SI reported lower drug use severity at 12 week if they received SC compared to CM + SC. Effects were small to medium.
Conclusions: Despite greater polysubstance use history, patients with suicide attempts did not show worse substance use outcomes than persons without suicidality. Patients with past SI fared better than those without suicidality on abstinence over 12 wk. Methadone clinics could be key points of entrance and continued services for suicide prevention.
Keywords: Methadone treatment; cocaine use disorder; opioid use disorder; suicidal ideation; suicide attempt.