The association between trichotillomania symptoms and emotion regulation difficulties: A systematic review and meta-analysis

Background Emotion regulation is postulated to play an important role in Trichotillomania (TTM). Whilst a growing number of studies have examined the relationship between emotion regulation difficulties and TTM symptoms, there have been no attempts to evaluate the overall strength of this association or the quality of the evidence base.Method This systematic review and meta-analysis aimed to synthesise findings from studies that have examined the relationship between emotion regulation difficulties and TTM symptoms, to inform future TTM treatment targets. We identified 17 studies that met inclusion criteria. From these studies, 32 correlation coefficients were extracted for meta-analysis. The Joanna Briggs Institute Checklist for Analytical Cross Sectional Studies was used to assess risk of bias amongst the included studies.Results There was a moderately sized association between TTM symptoms and ER difficulties, (r adjusted = 0.32, 95 % CI [0.28, 0.37], t = 15.58 (df = 11.86), p < 0.0001) that was moderated by sample size (F(df1 = 1, df2 = 30) = 4.597, b = -0.0001, SE = 0.0001, 95 % CI [-0.0002; 0.0000], p = 0.040) and differences between types of emotion regulation measures (Q(df = 1) = 4.06, p = 0.044).Limitations The data analysed was correlational, therefore causality was unable to be determined. Comorbidities were not able to be examined as a moderator.Conclusion This study provided a preliminary integration of the evidence and demonstrated that individuals with higher levels of TTM severity appear to exhibit decreased overall emotion regulation abilities and strategies.