Drug-Induced Impulse Control Disorders: A Prospectus for Neuroethical Analysis

There is growing evidence that dopamine replacement therapy (DRT) used to treat Parkinson’s Disease can cause compulsive behaviours and impulse control disorders (ICDs), such as pathological gambling, compulsive buying and hypersexuality. Like more familiar drug-based forms of addiction, these iatrogenic disorders can cause significant harm and distress for sufferers and their families. In some cases, people treated with DRT have lost their homes and businesses, or have been prosecuted for criminal sexual behaviours. In this article we first examine the evidence that these disorders are caused by DRT. If it is accepted that DRT cause compulsive or addictive behaviours in a significant minority of individuals, then the following ethical and clinical questions arise: Under what circumstances is it ethical to prescribe a medication that may induce harmful compulsive behaviours? Are individuals treated with DRT morally responsible and hence culpable for harmful or criminal behaviour related to their medication? We conclude with some observations of the relevance of DRT-induced ICDs for our understanding of addiction and identify some promising directions for future research and ethical analysis.