Six-month buprenorphine-naloxone treatment is associated with neurocognitive function improvement in opioid dependence

Abstract

Background and Aim: The number of longitudinal studies on cognitive functions in patients on buprenorphine-based agonist treatment is limited. Our objective was to assess the change in neurocognitive functions over the first 6 months of buprenorphine-naloxone (BNX) treatment for opioid dependence (OD) and compare cognitive functions on BNX and controls. Methods: We selected 60 patients with OD aged 18 to 55 years and 20 sex-matched controls; and excluded patients with other substance dependence, human immunodeficiency virus (HIV), head injury, epilepsy, and severe mental illness. We assessed patients thrice: at baseline, 3, and 6 months and Controls once. Cognitive tests included Wisconsin card sorting test (WCST), Iowa gambling task (IGT), trail making tests A and B (TMT-A and B), verbal and visual N-back test (NBT), and standard progressive matrices (SPM). We measured with-in group effect size with Cohen’s D (d). Results: A total of 24 participants completed at least one follow-up; 17 completed both follow-up assessments. All participants were men. At baseline, the patients performed worse than healthy controls in IGT, TMT-A, and B, and visual and verbal NBT. At 3 months, the performance of visual NBT improved significantly (d = 1.2 for NBT1; 1.3 for NBT2). At 6 months, additional performance improvements were seen in WCST (“perseverative error” d = 1.2), IGT (“net total score” d = 1.2), TMT-A (d = 1.1), and verbal NBT (“omission error” d = 1.7). Except for visual-NBT, results did not differ between patients and controls at both follow-ups. Conclusion: Cognitive flexibility, decision making, attention, working memory, and psychomotor speed showed improvements over 6 months of a stable dose of BNX.

Effects of Abstinence From Opioid on Neuropsychological Performance in Men With Opioid Use Disorder: A Longitudinal Study

“…The sociodemographic characteristics of the study participants, including mean age, educational status, and employment status, were comparable to that reported in other studies assessing participants with OUD. 5,14,15 The mean duration of opioid use among the participants was approximately 4 years. This was comparable to study conducted by Guerra and colleagues where the mean duration of use of heroin was 4.9 (SD = 2.1).…”

“…This was comparable to study conducted by Guerra and colleagues where the mean duration of use of heroin was 4.9 (SD = 2.1). 15 The majority of participants included in this study had history of use of semisynthetic opioids such as heroin (72%), with injecting drug use (IDU; 52%) as a predominant method of intake. This distribution was also in line with findings of 2 previous reviews done by Baldacchino and colleagues and Wollman and colleagues.…”

Response to the Federation of State Physician Health Program's Commentary

“…In addition, statistical analysis corrected what might be the "practice effect" of participants having the test administered at multiple time points. 5 Furthermore, as a controlled substance, buprenorphine is regularly monitored, especially to assess for effects that may impact performance. The unnecessary hurdle of suggesting that buprenorphine may significantly impact function over other psychotropics or medications used by physicians creates disincentives for those who may benefit from the option of buprenorphine in what we believe is a mutual goal for an effective, patient-centered treatment plan.…”

“…The study used several cognitive tests, assessing domains such as inductive and deductive reasoning, cognitive flexibility, executive function, impulsivity, attention, visual search and scanning, and verbal and visual working memory. In addition, statistical analysis corrected what might be the “practice effect” of participants having the test administered at multiple time points 5 …”

“…The data show that physician participants with OUD in PHPs have achieved long-term recovery rates that approach 80% at 5 years. 4,5 The education gap regarding PHP services is illustrated by the author's reference to a 2012 article, which contained inaccurate and outdated information. 6 For example, Washington state is listed as prohibiting buprenorphine, which is not the case.…”