The relationship between self-harm and alexithymia: A systematic review and meta-analysis

Self-harm, defined for the purpose of this review as any act of self-injury without explicit suicidal intent, is an increasing public health concern, with potential long-term implications for those who engage in it. Previous research has identified a correlational relationship between self-harm and alexithymia, an emotion processing deficit characterized by difficulties identifying and describing feelings, and an externally orientated thinking style. Through a systematic search of the literature, the current review examines the association between alexithymia and self-harm. A meta-analysis based on 23 studies found a significant, positive relationship between self-harm and alexithymia, with a medium effect size (g = 0.57, 95% CI 0.46-0.69). All 23 studies used the Toronto Alexithymia Scale (TAS20) to measure alexithymia. The alexithymia subcomponents difficulty identifying feelings and difficulty describing feelings were significantly associated with self-harm, but there was no significant association between self-harm and externally orientated thinking. The effect size of the relationship was significantly larger in adolescent samples compared with adult samples and in female compared with male samples. The definition of self-harm did not affect the effect size of the relationship between alexithymia and self-harm and the results are consistent with previous meta-analyses focused more narrowly on non-suicidal self-injury and, separately, suicidal behaviors. Heterogeneity between the included studies was high. The results support an affect regulation model of self-harm, in which self-harm is used to regulate an emotional experience that is poorly understood.