Hi and welcome!

If your son is just stating Latuda, it may take a few weeks to find it helpful.

Generally, psychiatrists determine if a patient is treatment-resistant.

I'd be concerned, too, if at 5 years my son was not improving.
Do you have access to his psychiatrist? Have you been able to tell the psychiatrist that you are concerned your son is not getting better?

I want to mention this again, if you are in the U.S., you might get a lot of support from NAMI's family programs. www.NAMI.org.

Please tell the psychiatrist of your concerns. If the psychiatrist is keeping his/her relationship strictly between the doctor and your son, that is fine. You can still express your concerns on the doctor's voicemail. Sometimes, when confidentiality laws forbid docs to talk, nothing forbids them from listening.

I hope this helps somehow.

WC