Hi, One of the major side effects of depression medication is weight gain. However, I am not too sure, what you mean by "at one shot?" If you took at one time, then probably that is not the cause, and if you mean you have taken large doses over a short period of time, yes, then it could be the cause. In any case, I suppose you are out of depression now and if you are not too sure, better see a doctor and find out if you still have depression, as people with depression tend to eat more, which could be another cause for excess weight gain. Also, please get your thyroid profile evaluated, which is one of the causes for excess weight, especially in women. Irrespective of the cause, start dieting (eat 1/3rd quantity less than what you are eating now, totally avoiding sweets, sugar, fried food, butter, ghee, cheese, chacolates, ice cream, and eat more of chappati and vegetables) and exercise more, REGULARLY, brisk walk 1 hour daily or better would be to join a gym or some workout places. It is better you DONT resort to any medication to reduce weight or any unknown concoction of drugs, as they may be more harmful. Hope I have answered your query, and I would be happy to help you more if you have any further questions. Regards, Dr. Rao.