Weight gain induced by psychotropic agents
==========================================

* Robert Dent
* Alan Gervais

## Weight gain is a common adverse effect of psychotropic agents

Although particular attention has been paid to the effects of atypical antipsychotic medications on weight gain, most antipsychotic agents, mood stabilizers and antidepressants have been associated with weight gain.1

## Estimates of weight gain reported in clinical trials are challenging to interpret

Clinical trials may underestimate relevant weight gain for several reasons. These include a short trial duration, the use of the “last observation carried forward” to handle data from study dropouts, a failure to account for differences in drug dosage, and differences between study groups in factors such as initial body mass index and use of other drugs that may cause weight gain.1 Marketing pressures have been cited in connection with the design and reporting of drug studies.2

## Weight gain and metabolic changes related to second-generation anti-psychotics may be overlooked

Weight gain and related comorbidities, such as glucose dysregulation and increases in triglycerides, total cholesterol and blood pressure, are not well monitored in patients taking antipsychotic medications.1 Second-generation antipsychotic agents can cause metabolic changes, even in the absence of weight gain. Monitoring for changes in cardiometabolic risk factors should be considered after the first 3 months of treatment and then every 6 months.3

## Weight gain induced by psychotropic medications is an important reason for nonadherence

Weight gain can have adverse psychological effects, which may offset the hoped-for benefit of drug therapy.4 Users of psychotropic drugs should be informed about the possibility of weight gain and other adverse effects.5 An expert consensus panel concluded that weight gain was an important adverse effect likely to lead to non-adherence to prescribed medications, which would place patients at a greatly increased risk of illness exacerbation and readmission to hospital.4

## One way to prevent weight gain is to (first prescribe a psychotropic agent less likely to cause weight gain

Psychiatric drug treatment is an iterative process. Appendix 1 (available at [www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.121044/-/DC1](http://www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.121044/-/DC1)) divides psychotropic agents according to their association with weight gain.1,6

## Footnotes

*   **Competing interests:** Robert Dent is a paid consultant and sits on the board for the Nestle Nutrition Institute and has received speaker fees from the Nestle Nutrition Institute and CMEatSEA. No competing interests declared by Alan Gervais.

*   This article has been peer reviewed.

## References

1.  Dent R, Blackmore A, Peterson J, et al. Changes in body weight and psychotropic drugs: a systematic synthesis of the literature. PLoS ONE 2012;7:e36889 doi:10.1371/journal.pone.0036889.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1371/journal.pone.0036889&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=22719834&link_type=MED&atom=%2Fcmaj%2F185%2F10%2F898.atom) 

2.  Spielmans GI, Parry PI. From evidence-based medicine to marketing-based medicine: evidence from internal industry documents. Bioethical Inquiry 2010;7:13–29.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1007/s11673-010-9208-8&link_type=DOI) 

3.  Correll CU, Manu P, Olshansky V, et al. Cardio-metabolic risk of second-generation antipsychotic medications during first-time use in children and adolescents. JAMA 2009;302:1765–73.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1001/jama.2009.1549&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=19861668&link_type=MED&atom=%2Fcmaj%2F185%2F10%2F898.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=000271150300019&link_type=ISI) 

4.  Velligan DI, Weiden PJ, Sajatovic M, et al. The expert consensus guideline series: adherence problems in patients with serious and persistent mental illness. J Clin Psychiatry 2009;70(Suppl 4):1–46.
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=19686636&link_type=MED&atom=%2Fcmaj%2F185%2F10%2F898.atom) 

5.  Schiff GD, Galanter WL, Duhig J, Koronkowski MJ, et al. Principles of conservative prescribing. Arch Intern Med 2011;171:1433–40.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1001/archinternmed.2011.256&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=21670331&link_type=MED&atom=%2Fcmaj%2F185%2F10%2F898.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=000294825100004&link_type=ISI) 

6.  1.  Lau DCW, 
    2.  Douketis JD, 
    3.  Morrison KM, 
    4.  et al
    
    Dent R, Habib R, Soucy L. Psychiatric issues in the management of obesity. In: Lau DCW, Douketis JD, Morrison KM, et al.; Obesity Canada Clinical Practice Guidelines Expert Panel. 2006 Canadian clinical practice guidelines on the management and prevention of obesity in adults and children. CMAJ 2007;176(8 Suppl):Online-40–4. Available: [www.cmaj.ca/content/suppl/2007/09/04/176.8.S1.DC1/obesity-lau-onlineNEW.pdf](http://www.cmaj.ca/content/suppl/2007/09/04/176.8.S1.DC1/obesity-lau-onlineNEW.pdf) (accessed 2012 Nov. 12).