A systematic review of addiction substitution in recovery: Clinical lore or empirically-based?

This systematic review synthesized the literature examining addiction substitution during recovery from substance use or behavioral addictions. A total of 96 studies were included with sample sizes ranging from 6 to 14,885. The most common recovery addictions were opioids (30.21%), followed by cannabis (20.83%), unspecified use (17.71%), nicotine (12.50%), alcohol (12.50%), cocaine (4.17%), and gambling (2.08%). Statistical results were provided by 70.83% of the studies. Of these, 17.65% found support for addiction substitution, whereas 52.94% found support for concurrent recovery. A total of 19.12% found no statistical changes and 10.29% found both significant increases and decreases. The remaining 29.17% of studies provided descriptive data, without statistical tests. Predictors of addiction substitution were provided by 22.92% of the studies and 11.46% included information on impact of addiction substitution on treatment outcomes. Overall, male gender, younger age, greater substance use severity, and presence of mental health disorders were associated with addiction substitution. Addiction substitution was associated with poorer treatment outcomes. A limitation of the present systematic review is the use of significance counting for the quantitative synthesis. More research examining changes in addiction during recovery would aid in the development of more effective treatments for addictive disorders and prevent addiction substitution.