I examined the relationship between the strength of a cognitive nonsuicidal self-injury (NSSI)-relief association and NSSI over time in the context of dialectical behaviour therapy (DBT) among individuals with borderline personality disorder (BPD). Self-injuring individuals with BPD were assessed for BPD and NSSI and randomly assigned to 6 or 12 months of comprehensive, standard DBT. Participants were re-assessed for NSSI every 3 months from the start of therapy for 24 months. The NSSI-relief association was assessed at baseline and again at 6 and 12 months after the start of therapy via the deliberate self-harm implicit association test (DSH IAT; Gratz et al., 2016). At baseline, participants also completed a measure of their motives for NSSI. Hypothesis 1 was that, at baseline, lifetime NSSI would be positively associated with the NSSI-relief association beyond self-reported emotion relief motives. Hypothesis 2 was that the NSSI-relief association would weaken over the course of one year after treatment began. Hypothesis 3 was that the NSSI-relief association at baseline would predict the rate of change of NSSI from baseline to the end of one year, such that a stronger NSSI-relief association would predict a slower rate. Hypothesis 3a was that the rate of change of NSSI from baseline to the end of one year would predict the rate of change of the NSSI-relief association from baseline to the end of one year, such that a greater rate of change of NSSI would predict a greater rate of change of the NSSI-relief association. Analyses revealed that lifetime NSSI was not associated with the NSSI-relief association beyond self-reported emotion relief motives. As well, the NSSI-relief association did not weaken over the course of one year. Finally, findings from parallel linear growth curve models did not support hypothesis 3 or 3a. These results suggest that the DSH IAT might not be sensitive to treatment effects in DBT for individuals with BPD in clinical populations. Findings also suggest that future research should investigate change in other processes that maintain NSSI, the association between DSH IAT D scores and NSSI consequences, and the relationship between NSSI and relief over time.
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Thesis advisor: Chapman, Alexander
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