Studies have documented problems of unwanted weight gain with SSRIs. Weight gain occurs most often after prolonged treatment with SSRIs although weight loss is common during the first few weeks of treatment.
For many patients, weight gain is an intolerable side effect. Meta-analyses have shown that although weight gain is a common side effect of antidepressants, the average weight gain per patient is small. For those patients who experience significant weight gain, it is likely that multiple factors in addition to drug mechanism are contributory, including genetic predisposition.
If significant weight gain occurs, it is typically gradual over the course of many months, and does not appear to depend on the dosage.
A weight change of 7% from baseline is considered clinically significant in a healthy adult. A 7% weight change translates to 11 pounds for a 150 pound person. Patients are willing to gain only an average of 5.37 pounds as a side effect of medication use in the treatment of a non-life-threatening psychiatric condition. Therefore, in this example (a 150 pound person), an approximate 5 pound weight difference exists between clinical significance (the area of practitioner’s concern) and the weight gain patients are willing to tolerate from SSRIs. Discontinuation of antidepressants occurs 62% of the time during the acute phase of treatment and 66% during the late phase of treatment due to side effects.
More importantly, it must be acknowledged that there are no definitive studies that clearly demonstrate the use of SSRIs cause weight gain in a majority of participants. However, many of the current studies demonstrate weight gain in some subjects, especially during long term treatment. Treatment for clinical depression is essential and should be continued for at least 1 year after response to prevent relapse and provide maintenance treatment.
Weight gain caused by SSRIs can affect a patient’s physical health, appearance, self-confidence, self-esteem and feelings of self-worth. A positive body perception is an important part of self image.