A Systematic Review of the Relationship between Momentary Emotional States and Nonsuicidal Self-Injurious Thoughts and Behaviours

Background: Nonsuicidal self-injury (NSSI) is associated with high levels of distress, co-morbid mental health issues, and elevated risk of suicide. Previous literature indicates that emotion regulation is the most endorsed function of NSSI. Experience Sampling Methodology (ESM) provides a powerful tool for investigating the moment-to-moment associations between emotional states and NSSI thoughts and behaviours. The aim of the current study was to systematically review and evaluate ESM research concerning the relationship between momentary emotional states and NSSI. Methods: A systematic search of electronic databases from date of inception to 16th April 2021 was conducted. This was supplemented through backwards citation tracking. A risk of bias assessment was completed prior to data synthesis. Results: Nineteen eligible studies were identified for inclusion in the review. Heightened negative affect was found to typically precede instances of NSSIT thoughts and behaviour. Results were less consistent for positive affect. Limitations: Sample sizes across studies were often small, meaningful effect sizes were not always reported, and non-validated measures of NSSI thoughts and behaviour were used during ESM assessments. Conclusions: The results support affect regulation models of NSSI, and demonstrate the value of ESM studies, specifically those sampling more than once per day, in plotting the temporal, “in-the-moment” characteristics of these processes.