Abstract
Background: Symptoms of Obsessive–Compulsive Disorder (OCD) sometimes do not improve despite being competently treated with known effective pharmacological and/or cognitive behavioural therapy with exposure and response prevention interventions. OCD symptoms that are particularly difficult to treat are related to harm /aggressive, sexually taboo and religious/blasphemous intrusive obsessional thoughts/images. Factors such as the vividness of the intrusive imagery, guilt, shame, cognitive inflexibility and inhibitory control deficits, are known to impact on OCD. Therefore it is important to further improve treatment given that the quality of life of patients with untreated OCD symptoms can be as equally poor as that of patients diagnosed with schizophrenia and in some cases worse. Imagery rescripting therapy is effective in reducing shame, guilt and the intensity of imagery vividness in trauma-based disorders such as Post-Traumatic Stress Disorder (PTSD). The ameliorative qualities of imagery rescripting may be of therapeutic benefit in OCD. Aim: This study explored the therapeutic utility of one-session imagery rescripting with homework practice in reducing image vividness, guilt, shame, cognitive inflexibility and impairment in motor inhibitory control linked to OCD related to harm/aggressive, sexually taboo and religious/blasphemous intrusive images. Methodology: A multiple baseline single-case experimental design was utilised with 6 adult participants recruited. One participant withdrew after the initial baseline phase and the visual graphed data analysis for 5 participants was conducted on scores on measures of vividness, shame, guilt and anxiety, with the Tau-U test utilised to assess trends between baseline and intervention phases. Clinical significance (CS) and reliable change index (RCI) calculations were used to assess changes in scores on global measures of OCD, depression and cognitive flexibilities before and after the intervention and at follow-up. A favourable ethical opinion was obtained from appropriate research ethics committees before data collection commenced. The study was conducted in accord with research ethics and governance requirements. Results: This study found that changes in intrusive imagery vividness, was only reported in one of the two patients whose intrusive imageries were associated with memories of past adverse experiences. It was also found that patients with intrusive imageries that did not have an association with an adverse memory also reported improvement in shame, guilt and OCD following imagery rescripting. The study also found that the OCD patients performed worse on the CANTAB – SSRT and ED tasks compared to the healthy normal group but similar to the OCD clinical controls, however, the improvements in set-shifting deficits and or in motor inhibitory impairment following imagery rescripting could not be established. Instead it was found that the impairments improved following repeated measurements at the baseline phase in the absence of treatment. Conclusion and Implications: Although only one patient supplied evidence consistent with imagery rescripting having therapeutic potential for OCD images, however from a broader view point the study demonstrated replication failure of this result across the participants. Furthermore, there was also no conclusive evidence to suggest imagery rescripting had significantly changed set-shifting and motor inhibitory impairments. Further investigation is required, taking into account of the study limitations and implications before one could comment for definite how the findings contribute to the current knowledge. Single case experimental design might not be particularly suitable for investigating neurocognitive improvement in treatment trials due to the nature of repeated measurements.