DIFFERENTIAL-EFFECTS OF THE D1-DA RECEPTOR ANTAGONIST SCH139166 ON POSITIVE AND NEGATIVE SYMPTOMS OF SCHIZOPHRENIA

In the present open study the effects of the D-1-dopamine antagonist S CH 39166 on positive and negative symptoms of schizophrenia (DSM-IIIR) were investigated. SCH 39166 was given orally according to a fixed do sage schedule (day 1:25 mg b.i.d; day 4:50 mg b.i.d.; day 7:100 mg b.i .d.; day 18:200 mg b.i.d.; day 21:225 mg b.i.d.). Seven patients compl eted 2 weeks, and five patients completed the study. The reason for pr emature withdrawal was lack of efficacy or refusal to take SCH 39166. In none of the patients a reduction of the BPRS or CGI score was found . As measured with the PANSS, a significant reduction was observed in the score of the negative subscale, whereas the positive symptoms scal e and general psychopathology score remained unaffected. Akathisia, ri gidity and hypokinesia were reported occasionally, although only mild in severity. The results of the present study do not support the hypot hesis that D-1-dopamine antagonists are clinically effective antipsych otics in schizophrenia, considering the fact that SCH 39166 had no eff ect on positive symptoms. The present study provides circumstantial ev idence for an effect of SCH 39166 on negative symptoms.