Does zoloft (sertraline) always casue weight gain....or is it the fact that you are feeling better that you just eat more? i do not want to gain weight.

Usually very little: All ssri antidepressants including zoloft (sertraline) cause a little weight gain on average. It's important to remember that everyone's different. Some lose a little, some gain a little — there's no guarantee what will happen to you specifically. When zoloft is given to large numbers of research subjects, they average a very small gain of about 2 lbs. Just feeling better does this too.

Increased appetite: All serotonin reuptake inhibitors (ssri) like zoloft (sertraline) increase the amount of serotonin available in the synapse. Serotonin also acts on the satiety center, so consciously or unconsciously your appetite is increased. Zoloft (sertraline) itself doesn't add the weight, but can increase your appetite. So if you watch your intake or exercise, you can avoid any weight gain.