Does zoloft (sertraline) cause weight gain? what is the best time of day to take it?

Zoloft (sertraline): Like most of the ssri's, zoloft can cause some weight gain -- but a little less likely than paxil (paroxetine). In some people it can be sedating, so you might want to experiment with taking it at night. Some people prefer it in the morning, and those are ones who don't experience any sedation.

Yes sometimes: All of the serotonin enhancing antidepressants can cause weight gain, some more than others. Zoloft (sertraline) tends to be middle of the road where it may or may not. In my experience, it's not particularly weight gaining. As for time of day, what determine this is the effect it has on you. You can start out taking it in the morning and if it makes you sleepy/tired, switch it to night.