[Behavioral disorders in Parkinson's disease. Genetic, pharmacological and medico-legal aspects]

Patients with Parkinson's disease (PD) may present neuropsychiatric and conduct disorders at different stages of the development of the disease that make treatment even more difficult.

The neurologist must be on the lookout for the possible appearance of alterations affecting impulse control, even from the early stages of the disease, so as to be able to prevent them or to plan a suitable adjustment of treatment. Some of the most common impulsivity disorders include hypersexuality, compulsive gambling and other addictive behaviours which, if left undetected and untreated, can end up having a destructive effect on the patient's socio-familial surroundings. Psychotic disorders (hallucinations, delusions) are often associated to advanced phases of PD and to the effect of dopamine therapy, and they are associated to a higher morbidity and mortality rate. Factors of a genetic or pharmacogenetic nature or a gene-environment interaction may account for the different individual susceptibility to disorders in the neuropsychiatric realm among patients with PD. It is wise to bear in mind the possible medico-legal implications that may stem from behavioral disorders, both for the patient and his or her family and for the physician, because situations could arise that trigger conflicts between confidentiality and preventing third parties from being harmed, as well as harm that can be attributed to the side effects of medicines.

The specialist must be familiar with, foresee and propose suitable treatment for behavioral and neuropsychiatric disorders in PD with potential medico-legal implications.