Treatment response trajectories and antipsychotic medications: examination of up to 18 months of treatment in the CATIE chronic schizophrenia trial.
BACKGROUND
Trajectory studies highlight heterogeneity in treatment response, although they are yet to systematically differentiate between antipsychotic medications.


OBJECTIVE
To compare treatment response trajectories across antipsychotic medication groups.


METHODS
Data were analyzed from Phase 1 of CATIE, an 18-month double-blind randomized controlled trial of chronic schizophrenia. Change on recurrent Positive and Negative Syndrome Scale (PANSS) administrations for 1124 patients was used to index treatment response trajectories up to 18 months. Trajectory groups were identified with mixed-mode latent class regression modeling. Groups were derived for all participants, and separately for completers, dropouts, and each antipsychotic medication (olanzapine, perphenazine, quetiapine, risperidone, ziprasidone) and then characterized.


RESULTS
Trajectory analysis of the entire sample identified that 18.9% of participants belonged to a group of responders. This figure increased to 31.5% for completers, and fell to 14.5% for dropouts. Olanzapine treated patients were significantly more likely than other treatment groups to belong to the trajectory of responders (n=69, 32.55%; Chi=20.13, df=2, p<.01). Separate trajectory analyses of each medication group showed that all medication groups showed two trajectories except olanzapine that had three trajectories and the only trajectory that attained a 20% PANSS reduction by endpoint.


CONCLUSIONS
Trajectories of treatment response differ between antipsychotic medications and demonstrate substantial heterogeneity in chronic schizophrenia.
Bar Ilan University, Israel. slevine@univ.haifa.ac.il
Stephen Z
SZ
Levine
Jonathan
J
Rabinowitz
Douglas
D
Faries
Anthony H
AH
Lawson
Haya
H
Ascher-Svanum
D000328:Adult; D000704:Analysis of Variance; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D017321:Clinical Trials, Phase I as Topic; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011569:Psychiatric Status Rating Scales; D016032:Randomized Controlled Trials as Topic; D012559:Schizophrenia / Q000188:drug therapy*; D016896:Treatment Outcome
D014150:Antipsychotic Agents