A positive relationship between antidepressant use and weight gain has consistently been demonstrated. A 4-year longitudinal Australian follow-up study published in BMJ Open examined the association between antidepressant use and weight gain, along with the interaction of unhealthy lifestyle factors.
The researchers used data from 2334 participants in the North West Adelaide Health Study, an ongoing community-based cohort study of adults from Adelaide, South Australia. The current study analyzed data from 2004 to 2006 (stage 2) and 2008 to 2010 (stage 3), including validated diet and lifestyle questionnaires, measured body weight, and medication use. The primary outcome measure was body weight change.
Of the 2334 participants, 188 (8.1%) had an annual mean of 1 to 2 antidepressant prescriptions, and 212 (9.1%) had >2 antidepressant prescriptions. Mean annual weight gain was 0.12 kg, 0.18 kg, and 0.28 kg in non-antidepressant users, low antidepressant users (1 to 2 prescriptions/year), and high antidepressant users (>2 prescriptions/year), respectively.
Multivariable regression models demonstrated a positive association between antidepressant use and weight gain, with high antidepressant users gaining an additional 0.22 kg per year (95% CI, 0.00-0.44). This association was due mainly to the use of selective serotonin reuptake inhibitors (SSRIs), with high SSRI users gaining 0.48 kg more than non-users (95% CI, 0.20-0.76). The association between SSRI use and weight gain was strongest in participants with a high intake of a Western diet, a sedentary lifestyle, and who were smokers.
A major limitation of this study was the fact that the total number of antidepressant users evaluated was relatively small, which limited the power of the investigators to conduct detailed subgroup analyses. The researchers emphasized the need for general practitioners to encourage their patients being treated with antidepressants to adopt healthy lifestyle behaviors.
Shi, Z, Atlantis E, Taylor AW, et al. SSRI antidepressant use potentiates weight gain in the context of unhealthy lifestyles: results from a 4-year Australian follow-up study. BMJ Open. 2017; doi: 10.1136/bmjopen-2017-016224.