Alexithymia-an independent risk factor for impulsive-compulsive disorders in Parkinson's disease

Impulsive-compulsive disorders (ICDs) are frequent side effects of dopaminergic medication in Parkinson's disease (PD). Alexithymia, a personality trait characterized by difficulties identifying and describing feelings and an externally oriented thinking style, has been linked to various impulse-control problems in the general population. In PD, the prevalence of alexithymia is approximately twice as high as in the general population. However, whether alexithymia is associated with ICDs in PD is currently unknown. We examined the relationship between self-reported ICDs and alexithymia in a sample of 91 PD patients (89 on dopaminergic medication). Additional self-report measures assessed impulsivity, depression, anxiety, behavioral inhibition/approach, and emotion-regulation strategies. We observed that alexithymia, and particularly difficulty identifying feelings and difficulty describing feelings, was significantly correlated with ICDs, even when controlling for impulsivity, anxiety, and depression. In addition, a group analysis revealed that PD patients with clinical and moderate levels of alexithymia had significantly more ICDs than non-alexithymic patients, suggesting that even moderately high alexithymia levels increase the risk for ICDs in PD. Our results identify alexithymia as an independent risk factor for ICDs in PD. Thus, the inclusion of alexithymia in the neuropsychiatric assessment of patients with PD may help identify patients at risk for ICDs.