Empirically Defining Treatment Response and Remission in Body Dysmorphic Disorder Using a Short Self-Report Instrument

Empirically Defining Treatment Response and Remission in Obsessive-Compulsive Disorder Using the Obsessive-Compulsive Inventory-Revised

In clinical trials of obsessive-compulsive disorder (OCD), clinical outcomes are generally measured using lengthy clinician-administered interviews. However, in routine clinical practice, many clinicians lack the time to administer such instruments. This study evaluated cutoffs for treatment response and remission in OCD using the self-rated Obsessive-Compulsive Inventory-Revised (OCI-R). Data from 349 patients in three clinical trials of cognitive-behavioral therapy for OCD were pooled for analysis. The OCI-R was compared to gold-standard criteria for response and remission based on the clinician-administered Yale-Brown Obsessive Compulsive Scale and the Clinical Global Impression Scale. The results showed that a ≥40% reduction on the OCI-R was the optimal cutoff for treatment response, with a sensitivity of 0.72 and a specificity of 0.79. For remission status, the optimal cutoff was ≤8 points on the OCI-R, with a sensitivity of 0.57 and specificity of 0.83. Results from additional analyses using the 12-item version of the OCI were similar. These cutoffs provide a simple and time-efficient way to help determine treatment response and remission in OCD when the administration of clinician-administered instruments is unfeasible.

The effect of body image dissatisfaction on goal-directed decision making in a population marked by negative appearance beliefs and disordered eating

Eating disorders are associated with one of the highest mortality rates among all mental disorders, yet there is very little research about them within the newly emerging and promising field of computational psychiatry. As such, we focus on investigating a previously unexplored, yet core aspect of eating disorders-body image dissatisfaction. We continue a freshly opened debate about model-based learning and its trade-off against model-free learning-a proxy for goal-directed and habitual behaviour. We perform a behavioural study that utilises a two-step decision-making task and a reinforcement learning model to understand the effect of body image dissatisfaction on model-based learning in a population characterised by high scores of disordered eating and negative appearance beliefs, as recruited using Prolific. We find a significantly reduced model-based contribution in the body image dissatisfaction task condition in the population of interest as compared to a healthy control. This finding suggests general deficits in deliberate control in this population, leading to habitual, compulsive-like behaviours (body checking) dominating the experience. Importantly, the results may inform treatment approaches, which could focus on enhancing the reliance on goal-directed decision making to help cope with unwanted behaviours.