Reduction of handwriting area and D-2 dopamine receptor occupancy in therapy with typical and atypical neuroleptic drugs

Beside the typical extrapyramidal motor symptoms such as rigidity, tremor, and dyskinesia, a reduction in handwriting area may occur under neuroleptic therapy. To date,the nature of the relationship between a reduction in han dwriting area and striatal D-2 dopamine receptor occupancy has remained unc lear, and it is not known whether such a reduction also occurs under treatm ent with atypical neuroleptic drugs. In 23 schizophrenic patients treated w ith haloperidol, haloperidol decanoate, risperidone, and clozapine, the han dwriting area was examined using a planimetric computer program. (123)l-iod obenzamide (IBZM) single photon emission tomography (SPET) was used to meas ure the D-2 dopamine rec statistically significant correlation was found be tween a reduction in handwriting area and D-2 dopamine receptor occupancy ( r = 0.86; P < 0.0001). The curve derived from the plotted data resulted in a hyperbolic function. The regression was present regardless of whether the patients were treated with typical or atypical neuroleptic drugs.