my son is 38 yrs old, with diagnosis at age 18. He still needs to be reminded to take his meds, he

Speaking for myself my symptoms are better when I'm medicated. By being supportive is a good way to help your son. I know in my life when I started getting support, it got alot better.

Linda,

I am sorry to hear your son doesn't want to take part in family outings or get involved in life, that is part of having the negative symptoms of schizophrenia as opposed to the positive symptoms.

Again, as I've suggested to others, I recommend you read Xavier Amador, Ph.D.'s book, I Am Not Sick, I Don't Need Help.  You need to establish a relationship of trust, and could benefit from using "motivational interviewing" (described in the book) to influence your son to take the meds.  When you know what goals he has, if any, you can tie his taking the meds into his achieving the goals.  You mention anger and frustration, residual symptoms.  Like Dave said the meds will help with the symptoms. 

The main thing is, you want to "get him more involved in life, family outings, etc."  I am sorry to say this might not be what he wants, or he may have residual negative symptoms, such as lack of motivation or desire or volition.  There are new drugs being researched every year that are trying to resolve the issue of treating negative symptoms, so be hopeful .  Even if the drug he is on doesn't seem to work, it's better for him to stay on the meds to maintain his brain functionality than to repeatedly go off them or skip or miss doses.

So I suggest a two-fold approach: read the book I recommended, and work to build a relationship of trust where you can use motivational interviewing to tackle the problem of medication non-compliance. 

I wish you the best.

Chri