Impulsive-compulsive disorders are frequent in patients with Parkinson’s disease (PD). Recently, a screening questionnaire and rating scale were developed for these disorders: the questionnaire for impulsive-compulsive disorders (QUIP) and QUIP-rating scale (QUIP-RS). We assessed the validity of these instruments in the German language in order to reevaluate the benefit and to obtain German screening tools in clinical practice. A convenience sample of 156 patients was assessed in Kiel and Vienna. The patients filled out the QUIP-current, the QUIP-anytime and the QUIP-RS. We validated the questionnaires against a gold standard diagnosis via receiver operating characteristic curves and determined optimal cut-off scores for the instruments. Excluding walkabout, which was not shown to be valid, sensitivities ranged from 60–92 % for the QUIP-current, 68–91 % for the QUIP-anytime, and 73–100 % for the QUIP-RS. Specificities were >71 % for QUIP-current, >69 % for QUIP-anytime and >62 % for QUIP-RS. With its very good sensitivities, the QUIP-RS is a valid instrument to assess impulsive-compulsive disorders and makes an early detection of behavioral disorders in PD possible. The QUIP-anytime was also shown to be a valid screening instrument. Both are expected to prove useful in scientific and clinical practice.Electronic supplementary materialThe online version of this article (doi:10.1007/s00415-014-7299-6) contains supplementary material, which is available to authorized users.

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.

In the German QUIP-RS scoring sheet of Supplementary material 6, the cutoff scores for hobbyism and punding are unfortunately exchanged. Correct cutoffs are 4 for hobbyism and 3 for punding. The online version of the original article can be found under

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