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. 2020 Apr 28;33(2):e100172.
doi: 10.1136/gpsych-2019-100172. eCollection 2020.

Delaying clozapine: how long is too long?

Tom Varghese M  1   2 , K S Jyothi  1 , K S Shaji  1 , Lekshmi Rita Venugopal  3
Affiliations

Delaying clozapine: how long is too long?

Tom Varghese M et al. Gen Psychiatr. .

Abstract

Background: Although clozapine is the most effective drug for treatment-resistant schizophrenia, its use remains restricted in clinical practice in India. The delay in initiating treatment with clozapine and its impact on disease outcome needs evaluation.

Aim: To identify the implications of delaying clozapine initiation in clinical outcomes among people with treatment-resistant schizophrenia.

Methods: Subjects with treatment-resistant schizophrenia, stabilised on clozapine monotherapy, were recruited from the outpatient clinic of a general hospital psychiatry unit offering tertiary care services in Thrissur district, Kerala, India. A retrospective cohort design was employed, and information on duration of illness, total duration of treatment and duration of treatment with clozapine was collected. Present symptom status was measured using the Positive and Negative Syndrome Scale. Factors associated with higher symptom scores were analysed using an independent sample t test, Spearman correlation and multiple linear regression.

Results: Forty subjects stabilised on long-term clozapine therapy formed the study sample. The mean dose of clozapine used in the study population was 200 mg. The mean duration of antipsychotic treatment before starting clozapine was 89.3 months (7.4 years). The duration of treatment before starting clozapine was found to have a significant positive association with the total Positive and Negative Syndrome Scale score (correlation coefficient 0.40; p=0.01) and negative symptom score (correlation coefficient 0.33; p=0.04). The multiple regression analysis adjusting for covariates showed that the duration of treatment before starting clozapine was an independent factor associated with a higher negative symptom score in the Positive and Negative Syndrome Scale (slope β=0.05; p=0.02; R2=0.27).

Conclusion: Poor treatment outcomes in treatment-resistant schizophrenia could be secondary to a delay in initiating clozapine therapy.

Keywords: psychopharmacology; schizophrenia.

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Conflict of interest statement

Competing interests: None declared.

Figures

Figure 1
Figure 1
CONSORT diagram. CGI, Clinical Global Impression; CONSORT, Consolidated Standards of Reporting Trials; ICD-10, International Classification of Diseases 10.
Figure 2
Figure 2
Duration of treatment before starting clozapine and negative symptom score in the Positive and Negative Syndrome Scale.
See this image and copyright information in PMC

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