Impulse control disorders and dopamine dysregulation in Parkinson's disease: a broader conceptual framework

Impulse control disorders (ICDs) and dopamine dysregulation syndrome (DDS) in Parkinson's disease are motivation-based behaviours that involve repetitive occurrences of impulsive and uncontrolled activity. Psychiatric classification is currently inconsistent and unclear. An accurate conceptualisation of these problems is important to guide research and treatment.

The review considers conceptual and methodological problems underlying the diagnosis of ICDs and the assessment of their severity. Whilst having features of obsessive-compulsive spectrum model, ICD-5 may bring them together for the first time into a single category of behavioural addictions. Whilst matching clinical and biological evidence, any such psychiatric classification in Parkinson's disease will remain complicated by the interactions of pathophysiology and medication and fail to capture the range of subthreshold but still clinically significant symptomatology.

A non-diagnostic, dimensional construct of disinhibitory psychopathology may be a useful tool to guide research and inform treatment. The role of dysphoria is suggested as a further important factor in driving some of these problem behaviours. This opens the opportunity for adjunctive psychological approaches in management.