One of the most common and frequent questions asked by patients is the relationship between psychiatric medications and their effect on weight loss after surgery. This is a summary of an article that was published in March 2011 issue of Bariatric Times magazine. The incidence of major depressive disorder is between 2-9% in general population. The World Health Organization reports increasing incidence of depression and other psychiatric illnesses.

There is a complex relationship that exists between depression and obesity. This relationship is even more complicated when one considers the sex of the patient. An example is that men with obesity are less likely to suffer from depressive disorders than normal weight men. Underweight men however are more likely to suffer from depressive disorders and suicidal ideation. This data comes from a study that included 40,000 individuals.

There are a number of different classes of psychiatric medications. These include tricyclic antidepressants (TCA), the newer selective serotonin reuptake inhibitors (SSRI), serotonin norepinephrine reuptake inhibitors (SNRI) and dopamine and norepinephrine reuptake inhibitors (DNRI). And then there are a few, such as Wellbutrin, that do not belong to any of those groups noted.

In general weight gain is more common with TCA medications. There are some in which some weight loss is also noted. The table below outlines a summary of weight neutrality, relative weight gain or weight loss for a number medication. The mechanism by which the weight gain or weight loss occurs is not clear for all medications.

The relationship between antidepressants, mood stabilizers, antipsychotic and weight gain is an example of how important it is for all health care providers to be aware off a patient’s medications and it’s possible side effect on weight gain.