Exploration of distress tolerance and its association with self-injurious behaviour and as a trans-diagnostic target for intervention

Abstract

PURPOSE: This thesis focuses on distress tolerance (DT) and its association with self-injurious behaviours (SIB) and as a trans-diagnostic target for intervention. The systematic review aimed to assess the association between DT and SIB, including both non-suicidal self-injury (NSSI) and suicidal self-injury (SSI). The empirical study aimed to evaluate the acceptability and feasibility of a trans-diagnostic DT group intervention for an acute inpatient setting.

METHODS: The literature was systematically searched for research that included measures of DT and SIB and conducted statistical analysis on the association between DT and SIB. A mixed methods design was utilised to assess the acceptability and feasibility of a six-session DT group intervention delivered in an acute mental health inpatient setting. The group was developed and piloted over a four-month period, during which time, 19 participants were enrolled in the study. The mixed method design included a multiple A-B single case series design, including ten participants and post-intervention qualitative interviews with 12 participants and three staff members.

RESULTS: Twenty papers met the inclusion criteria in the systematic review. Evidence for an association between DT and SIB was mixed, with bivariate correlation analyses providing little evidence of an association, and other statistical analyses providing little evidence of a direct association between DT and SIB. However, many papers found an indirect association between DT and SIB, with both high and low DT being indirectly associated with NSSI, and high DT being indirectly associated with SSI. Feasibility and acceptability was evidenced through high recruitment, treatment uptake, attendance, and low session attrition rates in the empirical study. Group level analysis demonstrated improvements in DT and psychological distress, with medium effect sizes. Case series analysis indicated systematic change on at least one measured variable between baseline and intervention phases for three participants. Qualitative themes triangulated findings in relation to positive acceptability and learning new coping skills, which was also evidenced in enhancement of self-reported coping skills use post-intervention. Conclusion: There was some evidence for an indirect association between DT and SIB in the literature reviewed, with both high and low DT being indirectly associated with NSSI and high DT being indirectly associated with SSI. The pilot study indicated that a trans-diagnostic DT group intervention in an acute inpatient setting is feasible and acceptable, with initial findings indicating that the intervention may have contributed to improvements in DT and psychological distress, and enhanced coping skills use post-intervention.