Well, he certainly doesn't need Lexapro, since it didn't provide any benefit to him. The question now is: "What benefit is the Zoloft providing?" Sounds like you are not seeing any benefit yet. 4 months is plenty long enough time to give a drug to work. See what happens over the next few months. There is a widespread expectation that every psych patient needs to be on psych meds. Even when the patient does not become more well on them, doctors and the public tend to say, "Well, he would probably be worse without the meds." I don't buy that. Sometimes the solution to a person's difficulty is something that cannot be put in a pill.

Difficulties that bring a person to the attention of psychiatrists tend to be chronic issues, I believe. If taking a med improves life for your son: fine. Most likely he needs to develop maturity in some area where it is lacking. With time and experience, he may. Lots of people who take meds eventually go off them and find that their lives are not worse because of that. I believe anyone taking a med long-term should periodically come gradually off it to see if it really is doing anything positive. (Unless there is some compelling reason to believe that would be dangerous.)

If your son takes a drug that seems to contribute to weight gain of great magnitude, that - to me - would be a good reason to not take that drug. Morbid obesity causes great harm, both physically and psychologically.

Not everything that causes a person to have great difficulty coping with life is a medical problem. So medical solutions are not always the answer, but we live in a culture that tends to think they are.

Your son's therapist felt the Lexapro wasn't strong enough? I'm not aware that Zoloft is necessarily stronger than Lexapro. That's not how you compare antidepressants. I presume the drugs are being ordered by a physician and on some basis other than recommendations from the therapist. Non-physicians, including therapists, have a lot of misconceptions about psychotropic drugs. I've gone into my psychiatrist to say that my therapist recommended this or that drug change, just to see my pdoc shake his head back and forth, indicating "No" and obviously wishing that therapists would stick to what they are qualified to have opinions on.

I hope things improve for your son.