Habituation of distress during exposure and its relationship to treatment outcome in post-traumatic stress disorder and prolonged grief disorder.

Reliving distressing memories is a core component of treatments for post-traumatic stress disorder (PTSD) and prolonged grief disorder (PGD). There is little understanding of how reliving these memories functions in the treatment of these disorders. This study investigated whether reliving functions comparably in the treatment of PTSD and PGD, and whether it is comparably related to treatment outcome. This study conducted a reanalysis of patients with either PTSD ( = 55) or PGD ( = 45) who underwent treatments that comprised at least four sessions of reliving memories of either their traumatic experience or the loss of the deceased person. PTSD participants displayed greater habituation of distress across sessions during reliving than PGD participants. Between-session reduction in distress during reliving was associated with symptom remission in PTSD, but this pattern was not observed in PGD. This pattern of findings indicates that although reliving appears to be a useful strategy for treating both PTSD and PGD, this strategy does not function comparably in the two conditions and may involve distinct mechanisms.