The prevalence of tardive dyskinesia after a nine month naturalistic randomized trial comparing olanzapine with conventional treatment for schizophrenia and related disorders.

AIMS OF THE STUDY

To assess the impact of olanzapine versus conventional neuroleptic therapy among subjects with schizophrenia on ratings of tardive dyskinesia (TD).

METHOD

The naturalistic study was conducted in three psychiatric hospitals in Brazil. Patients had a diagnosis of schizophrenia and related disorders (DSMIV) and with a BPRS score>24. Patients were evaluated by means of the PANSS scale for symptomatology (Kay et al. 1986), the Clinical Global Impression, The UKU side effect rating scale (Lingjaerde et al. 1987), and the Tardive Dyskinesia AIMS scale (Guy et al. 1976). Patients were seen by the treating physician routinely while hospitalized and then monthly on an out-patient basis. All scale assessments were repeated after 9 months of discharge.

RESULT

The sample was comprised of 190 patients (99 in the olanzapine and 91 in the standard treatment), with a completion rate of 88.2% for olanzapine and 84.9% for the conventional treatment (p=0.385, n. s.). The mean change from baseline in the PANSS total score favored olanzapine regarding negative symptoms (2.3, 95% C. I. 0.6-4.1, p<0.001); and general psychopathology (4.0, 95% C.I. 0.8-7.2, p<0.02) factors. TD was defined by applying Morgenstern & Glazer (1993) and Schooler & Kane (1982) criteria, on the basis of the AIMS scale. Both results favored olanzapine at the end of the follow-up (Morgenstern & Glazer: 25.6% versus 56.3%; Schooler & Kane: 16.3% versus 45.2%). At the end of the follow-up, by using the overall rating of the AIMS scale, the presence of TD was 2.3% for olanzapine (2/87), and 16.7% (12/72) for the conventional treatment.

CONCLUSIONS

The results of this open label naturalistic trial showed that olanzapine had an impact on negative symptoms, decreased general psychopathology and reduced the risk of tardive dyskinesia.