2 people in my graduating class from High School committed suicide. No JWs in my old circuit that I know of have done so, but the operative term here is "that I know of".
An interesting corollary to this topic would be "have YOU ever thought of suicide?". The answer in my case is "yes", although I have dismissed the idea for the present and the foreseeable future. I'm sure a lot of people leaving the witnesses have at least thought about it. It's a morbid topic, but an important one to discuss. The organization so consumed our lives for so long that upon leaving that it may seem like we have nothing left. The trick is to find new things to replace what we gave up, and sometimes to rediscover things about ourselves we never knew we lost in the first place.