The Effect of Cognitive Fusion on Change in PTSD and Depression Symptom Severity in Veterans Engaged in Group Psychotherapy

Cognitive fusion occurs when people experience their thoughts as literally true and allow them to dictate behavior. Fusion has been shown to be associated with increased symptoms of post-traumatic stress disorder (PTSD) and depression; however, the association between change in cognitive fusion, PTSD, and depression symptoms has been relatively uninvestigated. Our study aims to examine the associations between PTSD, depression symptoms, and cognitive fusion in Canadian veterans from pre- to post-treatment. Clients (N = 287) completed measures of PTSD symptom severity, depression symptom severity, and cognitive fusion at pre- and post-treatment. Our results supported that pretreatment PTSD and depression symptom severity were found to be negatively associated with changes in pre- to post-treatment cognitive fusion, while pretreatment cognitive fusion was not associated with changes in depression or PTSD symptoms. Furthermore, pretreatment depression symptoms predicted pre- to post-treatment changes in PTSD symptoms. However, pretreatment PTSD symptoms did not predict changes in depression symptoms. These findings highlight the importance of understanding the bidirectional associations between PTSD, depression, and cognitive fusion. Furthermore, our results are indicative of PTSD and depression symptoms playing a role in the change in cognitive fusion (e.g., defusion) and of depression playing a larger role in the maintenance of PTSD symptoms. Theoretical and practical implications are discussed.