Clinical characteristics of neuroleptic-induced parkinsonism

In order to characterize the clinical spectrum of neuroleptic-induced parkinsonism (NIP), we studied a population of consecutive psychiatric in-patients treated with neuroleptics for at least two weeks, who were diagnosed by their psychiatrist as having parkinsonism. Parkinsonism was confirmed by a movement disorders specialist who performed neurological assessment including the motor examination and the activities of daily living (ADL) sections of the Unified Parkinson's Disease Rating Scale (UPDRS), and the Hoehn and Yahr (H&Y) staging. Seventy-five patients (54 males), aged 46 ± 13 years (range 21 to 73 years) were included in the analysis. The mean duration of neuroleptic therapy was 15 ± 12 years, while 61% were treated for more than 10 years. Most of the patients (n = 66, 88%) were scored as H&Y stage 2.5 or less. Rest tremor was present in 44% of the patients, and usually persisted in action. Forty-one patients (61%) had symmetrical involvement. Parkinsonian signs were significantly more common and pronounced in the upper in comparison with the lower limbs (p = 0.0001). Gait disturbances were mild and freezing of gait was very rare (n = 2). Neither age nor duration of therapy or their interaction affected the total motor score or any of the motor sub-scores. In conclusion, NIP differs from PD for more bilateral involvement with relative symmetry, and by affecting upper limbs more often than the lower ones. NIP tends to be associated with the triad of bradykinesia, tremor and rigidity while PD tends to involve gait and posture more often. NIP develops unrelated to duration of neuroleptic treatment or age of the patient, suggesting an individual predisposition to blockage of the dopaminergic receptors.