Responsibility and hand washing behaviour

Dr. Jack Rachman's contributions to our understanding and treatment of obsessive-compulsive disorder

BACKGROUND AND OBJECTIVES

This paper reviews the development of the cognitive-behavioural model of obsessive-compulsive disorder (OCD) through the work of Dr. Jack Rachman and the research his ideas inspired or shaped.

METHODS

A narrative review of Rachman's work and important developments in related areas was conducted.

RESULTS

Rachman was highly responsive to theoretical and empirical developments in the field, and continuously developed his model of OCD over the course of his career. Key developments in his thinking and of those in related areas are described.

LIMITATIONS

This is a narrative review that highlights important developments in the cognitive behavioural model of OCD only.

CONCLUSIONS

The CBT model of OCD has strong empirical support and CBT treatment is the most effective psychotherapy. Continued development in our understanding of attachment and in the persistence of compulsions is warranted.

On the automatic detection of enacted compulsive hand washing using commercially available wearable devices

BACKGROUND

Compulsive hand washing is one of the most frequent compulsions and includes highly ritualized, repetitive hand motions. Developing an algorithm that can automatically detect compulsive washing with off-the-shelf wearable devices is a first step toward developing more sophisticated sensor-based assessments and micro-interventions that might ultimately supplement cognitive behavioral therapy for obsessive-compulsive disorder (OCD).

OBJECTIVE

The main objective was to establish whether enacted compulsive hand washing can be distinguished from routine hand washing. This distinction will inform future research on the development of an algorithm that can automatically detect compulsive hand washing.

METHOD

Twenty-one participants were trained individually to wash their hands according to 1 of 5 scripted hand-washing procedures that were based on descriptions of pathological compulsive washes and additionally to wash their hands as they usually would, while wearing a smartwatch. Washes were video recorded to obtain validation data. To generate a baseline model, we opted to extract well-known features only (mean and variance of each sensor axis). We tested four classification models: linear support vector machine (SVM), SVM with radial basis functions, random forest (RF), and naive Bayes (NB). Leave-one-subject-out cross-validation was applied to gather F1, specificity, and sensitivity scores.

RESULTS

The best-performing parameters were a classification window duration of 10 s, with a mean-variance feature set calculated from quaternions, rate of turn, and magnetic flux measurements. The detection performance varied with the particular enacted compulsive hand wash (F1 range: 0.65-0.87). Overall, enacted compulsive and routine hand washing could be distinguished with an F1 score of 79% (user independent), a sensitivity of 84%, and a specificity of 30%.

CONCLUSIONS

Our analysis of the sensor data demonstrates that enacted compulsive hand washing could be distinguished from routine hand washing with acceptable sensitivity. However, specificity was low. This study is a starting point for a series of follow-ups, including the application in individuals diagnosed with OCD.