Eating disorders and morbid obesity have become common over the recent years. Laparoscopic gastric bypass surgery is known as one of the most effective methods for weight loss. Due to the rarity of studies regarding the association of depression and surgery, we aimed to compare the levels of depression in patients with excessive obesity before and after gastric bypass surgery.

This Quasi-experimental study performed on 40 obese patients who underwent gastric bypass surgery with BMI higher than 40 or between 35 to 40 (with FBS > 100 mg/dL) in Ghaem hospital, Mashhad University of Medical Sciences, Mashhad, Iran during September 2011 to September 2012.The Beck depression inventory (BDI) was performed one week before, and three and six months after operation and changes in BMI and BDI were evaluated using ANOVA with repeated measures.

40 obese patients with the mean age of 34.20 ± 11.32 years old and mean BMI of 45.31 ± 2.56 kg/m² were studied. Also, male to female ratio was 7:1. Average of BDI, before and three months after the operation was 27 ± 11.31 and 18.50 ± 9.718, respectively (P < 0.001). The value of 17 ± 7.071 was also obtained six months after the surgery which significantly was decreased compared to patient’s BDI (27 ± 11.31) before the operation (P < 0.0001).

It can be concluded that depression level of the patients was decreased after the surgery and the recovery progressed gradually.