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Evidence summaries

Antipsychotic-Induced Weight Gain

Both conventional and newer antipsychotics appear to be associated with weight gain, which appears to be 3- to 4-fold greater in patients with first-episode psychosis compared to patients with chronic psychotic disorders. Level of evidence: "B"

A systematic review 1 including 81 studies with a total of 1823 subjects was abstracted in DARE. Both conventional and newer antipsychotics were associated with weight gain. The mean estimated weight gain at 10 weeks was for chlorpromazine 2.58 kg, haloperidol 1.08 kg, olanzapine 4.15 kg, risperidone 2.10 kg, thioridazine 3.19 kg. Among the newer agents, clozapine appears to have the greatest potential to induce weight gain (4.45 kg), and ziprasidone the least (0.04 kg). The differences among newer agents may affect compliance and health risk.

A systematic review 2 including 51 RCTs with 14 769 participants was abstracted in DARE. Studies compared antipsychotics (olanzapine, risperidone or haloperidol) with either placebo or an active comparator and reported data regarding weight change by body mass index (BMI) in patients (age range 16 to 65 years) with psychotic disorders but without any other psychiatric medication.

  • Drug-induced weight gain in patients with chronic psychotic disorders:
    • Short-term trials (33 RCTs; follow-up 6-28 weeks): olanzapine from 1.80 to 5.40 kg; risperidone from 1.0 to 2.30 kg; haloperidol from 0.01 to 1.40 kg.
    • Long-term trials (8 RCTs; follow-up 12-18 months): olanzapine from 2.0 to 6.2 kg; risperidone from 0.4 to 3.9 kg; haloperidol from -0.70 to 0.4 kg.
  • Drug-induced weight gain in patients with first-episode psychosis:
    • Short-term trials (6 RCTs; follow-up 10-12 weeks): olanzapine from 7.1 to 9.2 kg; risperidone from 4.0 to 5.6 kg; haloperidol from 2.6 to 3.8 kg.
    • Long-term trials (4 RCTs; follow-up 1-2 years): olanzapine from 10.2 to 15.4 kg; risperidone from 6.6 to 8.9 kg; haloperidolfrom 4.0 to 9.7 kg.

Comment: The quality of evidence is downgraded by limitations in review quality (questionable reviewing process in study selection and quality assessment, pooling of heterogeneous studies).

References

  • Allison DB, Mentore JL, Heo M, Chandler LP, Cappelleri JC, Infante MC, Weiden PJ. Antipsychotic-induced weight gain: a comprehensive research synthesis. Am J Psychiatry 1999 Nov;156(11):1686-96. [PubMed] [DARE]
  • Alvarez-Jiménez M, González-Blanch C, Crespo-Facorro B, Hetrick S, Rodríguez-Sánchez JM, Pérez-Iglesias R, Vázquez-Barquero JL. Antipsychotic-induced weight gain in chronic and first-episode psychotic disorders: a systematic critical reappraisal. CNS Drugs 2008;22(7):547-62. [PubMed] [DARE]

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