AbstractObjectiveThere is a dearth of high-quality systematic evidence on the impact of opioid substitution medications on mental health. We compared mental health outcomes between opioid medications and placebo/waitlist, and between different opioids.MethodsThis systematic review and meta-analysis of randomized clinical trials (RCTs) was pre-registered at PROSPERO (CRD42018109375). Embase, MEDLINE, PsychInfo, CINAHL Complete, and Web of Science Core Collection were searched from inception to May 2020. RCTs were included if they compared opioid agonists with each other or with a placebo/waitlist in substitution treatment of patients with opioid use disorder, and reported at least one mental health outcome on a span of more than 1-month post baseline. Studies with psychiatric care, adjunct psychotropic medications, or unbalanced psychosocial services were excluded. Primary outcomes were comparison of depressive symptoms and overall mental health between opioids and placebo/waitlist. Random effects model was used for all the meta-analysis.ResultsNineteen studies were included in the narrative synthesis and 15 in the quantitative synthesis. Hydromorphone, diacetylmorphine (DAM), methadone, slow-release oral morphine, buprenorphine, and placebo/waitlist were among the included interventions. Based on network meta-analysis for primary outcomes, buprenorphine (SMD (CI95%)= −0.61 (−1.20, −0.11)), DAM (−1.40 (−2.70, −0.23)), and methadone (−1.20 (−2.30, −0.11)) were superior to waitlist/placebo on overall mental health. Further direct pairwise meta-analysis indicated that overall mental health improved more in DAM compared to methadone (−0.23 (−0.34, −0.13)).ConclusionsIt appears that opioid medications improve mental health independent of psychosocial services. Potential contribution of other factors needs to be further investigated.
Opioid substitution treatment is linked to reduced risk of death in opioid use disorder
