Can antidepressants increase the risk of weight gain?

Can antidepressants increase the risk of weight gain?

A new study published in The BMJ today has found that long term use of antidepressants is linked to the increase in risk of weight gain over a five year period.

The observational study showed that patients prescribed with any of the 12 commonly used antidepressants were more likely to experience weight gain than those not taking any medication. There was a greater risk in those in the second and third years of treatment.

Obesity and weight gain is a growing issue globally. In the UK alone, approximately 60% of adults are currently classed as overweight or obese.

Cases of depression are common in severely obese people, which in turn is seeing an increase in the rate of antidepressant prescribing. This could have an impact on public health.

What did the study entail?

The researchers analysed body weight and body mass measurement data from the UK Clinical Practice Research Datalink (CPRD) for over 300,000 adults with an average age of 51.

Participants were grouped according to body mass index (BMI), from normal weight to severely obese and whether they were prescribed an antidepressant in a given year.

The results

It was found that for every 59 people taking antidepressants, one extra person would gain at least 5% weight over the period of the study.

In the first 12 months of treatment, no association was found, however, during the second and third years of treatment the risk was much greater, with the findings showing that during the second year of treatment, there was a risk of gaining at least 5% weight was 46% higher than in the general population.

What the experts say

Lead author of the study Dr Rafael Gafoor from King’s College London, UK, said: “It’s important to stress that no patients should stop taking their medication and that if they have any concerns they should speak with their doctor or pharmacist.”

The authors said that whilst antidepressant treatment should always be offered to those with moderate or severe depression, alternatives such as cognitive behavioural therapy may be more ideal for those with milder depression.

Alessandro Serretti and Stefano Porcelli, from the University of Bologna, Italy, authors of linked editorial, concluded: “Currently, we are still unable to identify patients at higher risk of weight gain with antidepressants. Hopefully it will be possible in the not too distant future to identify a genetic predisposition and recognise those at higher risk before treatment is started.”

Press release: The BMJ

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