Previous research has shown an association between people who have had clinical depression and obesity.
But does having a major clinical depressive episode — or the drugs used to treat depression, called antidepressants — increase the risk of becoming obese?
Researchers looked at data from the Canadian National Population Health Survey (NPHS), a longitudinal study over 10 years of a representative sample of household residents in Canada.
The incidence of obesity, defined as a body mass index (BMI) of 30, was evaluated in respondents who were 18 years or older at the time of a baseline interview in 1994. Major depression was assessed using a brief diagnostic instrument.
The researchers found that the risk of obesity was not increased in association with being diagnosed with a major clinical depressive episode.
The strongest predictor of obesity was a BMI in the overweight (but not obese) range. Effects were also seen for (younger) age, (female) sex, a sedentary activity pattern, low income and exposure to antidepressant medications.
Unexpectedly, the researchers found significant effects for a specific type of newer antidepressant medications — serotonin-reuptake-inhibiting antidepressants (SSRIs) and venlafaxine. The researchers did not find any significant effects for older tricyclic antidepressants nor antipsychotic medications.
The researchers concluded that clinical depression in itself does not appear to increase the risk of obesity.
The previous cross-sectional associations that have been reported in the research literature probably represent an effect of obesity on depression risk, said the researchers. Treatment of depression with antidepressants medications may be associated with an increased risk of obesity, and strategies to offset this risk may be useful in clinical practice.
Source: Psychotherapy and Psychosomatics