Impulse Control Disorders in Parkinson’s disease: predominant role of psychological determinants

Objectives: Impulse Control Disorders (ICDs) in Parkinson’s disease (PD) have previously almost exclusively been considered to result from anti-parkinsonian medication. However, this biomedical perspective has failed to achieve a full understanding of the phenomenon and it is argued that a failure to consider psychological factors is a critical omission. Design: The present study examined the predictive relationship between ICDs in PD and a range of psychological measures, whilst controlling for a number of biomedical determinants. Main outcome measures: One hundred participants with idiopathic PD completed questionnaires that assessed demographic and clinical characteristics, psychological measures and the presence of ICDs (QUIP-RS). Results: Increased use of a ‘negative’ coping strategy, stronger illness identity, more emotional illness representations and stress were found to be significant predictors of ICDs, and different psychological predictors were associated with different ICDs. Medication was not found to predict ICDs in the presence of psychological factors, either when total treatment levels were considered or when agonist dose was considered alone. Conclusions: This study provides the first quantitative evidence of a predominant predictive relationship between psychological factors and ICDs in PD. The results suggest that psychological interventions may have a useful therapeutic role to play for ICDs in PD.