Association between alexithymia and substance use: A systematic review and meta‐analysis

Alexithymia has been associated with substance use, but the magnitude of the association has not been evaluated and sub‐group differences, if any, are unknown. The aim of this meta‐analysis is to systematically review the association between alexithymia and substance use (alcohol or illicit drugs). We identified studies through a systematic review of PubMed and Web of Science and obtained a total of 52 publications using the Toronto Alexithymia Scale‐20 scale. Random effects meta‐analysis was used to evaluate the overall and sub‐group associations. Of the studies, 50 were cross‐sectional and two longitudinal. Alexithymia was associated with any substance use (Cohen’s d = 0.62, 95% confidence interval [CI] 0.49–0.76), with little difference between estimates for use of alcohol or illicit drugs. A stronger association was observed for the alexithymia dimension “Difficulty in Identifying Feelings” (d = 0.64, 95% CI = 0.47–0.81) and “Difficulty in Describing Feelings” (d = 0.44, 95% CI = 0.32–0.55) than for “Externally Oriented Thinking” (d = 0.19, 95% CI = 0.09–0.28). The association was stronger in studies with clinical patient populations (d = 0.83, 95% CI = 0.62–1.05) than in those investigating general or student populations, and in studies with a majority of male rather than female participants. These findings suggest a strong overall association between alexithymia and substance use and a very strong association among clinical patient populations. The association may be stronger with the emotion‐related dimensions than with the cognition‐related dimension of alexithymia. As nearly all the studies were cross‐sectional, more longitudinal studies are needed.