I was afraid to try hallucinogens for a very similar reason. My uncle did lots of acid and shrooms, and he just so happens to be nuts.
One of my friends trips very frequently, and he has some mental health issues as well.
After trying shrooms several times and acid once, I have come to this conclusion: Hallucinatory substances have the potential to unlock your minds true state. I mean if you have mental health issues, they may become more apparent. At the same time, these substances have the ability to unlock true happiness.
I took acid last weekend, and during the weeks prior I found myself feeling anxious and slightly depressed at times. During and after my acid trip, however, I was thinking about what was making me feel anxious and depressed. I was able to realize that my problems are nothing more than concern over nothing.
Even today, I feel wonderful. My mood has improved drastically, and my Outlook on things is way more optimistic, including the things that upset me previously.
My advice would be to trip. If you come out of the trip feeling down or depressed, talk to someone about these issues. I was considering counseling before I tripped, but things that seemed overwhelming now appear simple and easy to deal with.
Hope this helps!