The connection between antidepressants and weight gain is a concern for many people taking the medications. Up to 25% of people on antidepressants gain 10 pounds (4.5 kilograms) or more over the long term. There are several possible reasons for the link between antidepressants and weight gain, including changes in appetite, metabolism, and chemical receptors in the brain. Although weight gain is possible with numerous antidepressants, it is a less common side effect with certain types, so some people might benefit from switching medications. There are also other ways to avoid or mitigate the amount of weight gain, like eating healthy and getting exercise.
Studies have shown that there is an association between antidepressants and weight gain. This is particularly true with tricyclic medications, monoamine oxidase inhibitors (MAOIs) and some selective serotonin reuptake inhibitor drugs (SSRI). People who take SSRI drugs gain an average of 5 pounds (2.3 kg) after a year. In some cases, people might see weight loss in the first few weeks, but over the long term, they gain weight.
Although there is controversy regarding the reasons behind the connection between antidepressants and weight gain, there are several possible explanations. The weight gain could be due to an increase in appetite and changes in metabolism. For some, antidepressants cause them to crave and eat more carbohydrates, which can lead to weight gain. Also, since depression can cause weight loss, recovering from depression with antidepressants can result in weight gain as people begin to feel better and eat more. Additionally, antidepressants that block the histamine and muscarinic acetylcholine receptors in the brain can affect the brain chemistry that influences weight gain.
Some people might find that the correlation between antidepressants and weight gain is weakened by switching to a different medication. For example, the antidepressant buproprion is rarely associated with weight gain. It should be noted, however, that different antidepressants will not work the same for everyone. Certain antidepressants might work better for controlling weight gain but not help as much with the depression. In some cases, doctors might recommend taking two different kinds of antidepressants to manage both the weight gain and depression.
Furthermore, eating healthy and getting plenty of exercise can mitigate the effects of antidepressants and weight gain. Exercising can also help people feel less depressed, possibly reducing the need for antidepressants, and thus lessening the amount of weight gain as a side effect. People should be wary of cutting calories too much, however, because it can negatively affect the brain chemistry and cause more depression.