I knew several who attempted (myself included, thankfully, I failed.) and a few who succeeded.
Danny Hayes, he had converted while in high school, he was dating a girl whose mother was a JW. They both ended up getting baptised, but broke up. Danny was very zealous; after breaking up with Rhonda he really didn't seem to want to have anything to do with dating, but was obsessed with the ministry. Several years passed, I think he pioneered, but I cannot recall clearly at the moment. I know he wanted to be an MS, but can't remember if he was ever appointed. (This all happened in the mid-to-late eighties so my memory isn't great on it.) He was very sweet and well-intentioned, but sort of ended up relegated to the "weirdos" crowd in our congregation. Eventually, he became inactive, and I think at one point he may have been DF'd. The rumors started that he was dealing drugs (never verified) and soon afterwards, news of his suicide began to circulate. I heard that he shot himself, but prior to doing so, he plastic tarps all over the room in order to minimize the cleanup for whoever found him. So sad, he was a very kind and caring boy.
In the late 80's early 90's, My friend Barb's brother shot himself in his parents backyard. He was in his twenties, and was a well-respected MS, played the guitar and sang at gatherings, everyone really liked him. He was on lithium and the claim was that his dosage was incorrect (basically, the JW's placed the blame on the meds, because of course, in their minds, if he hadn't been on those, everything would have been fine ). While the dosage may have been incorrect, I always wondered, "what about the reason he was on the meds to begin with?" But of course, you couldn't talk about that, because JW's are the happiest people on earth!
Early 90's - Harry Geyer (sp?) drove to a field and asphyxiated himself via a hose from his exhaust which he put in the window and rolled up as far as it would go. Before his wife Anne had converted to JWism, he had been sentenced to prison for killing someone while drink driving. He was placed in a halfway home and she had to go and pick him up and drop him off every day for his job at Deputy Dawg's coney restaurant. She would sometimes have to do this while out in service, so we would have to take two cars into the territory. I always felt so bad for her, she had this old beater car that would stall and break down on her all of the time. She stayed in the marraige though, because she was told that her persistance might persuade him to convert too. He did, and they had a child. I think his son was about six years old when his dad killed himself. Harry was apparently "addicted" to pain killers (he had to walk with a cane as a result of the accident) and was going to be DF'd for it (or perhaps he already had, I can't recall exactly.) A few years later, Anne married another brother, an MS who suffered major mental issues but they were sort of overlooked due to his zeal in the ministry. (He was part of the "weirdo" crowd mentioned earlier). I felt bad for her son. That man had no business being a father, even a step-father. He was very unstable in my mind, I remember when my father's DA announcement was made, he immediately raced over to where my family was sitting and started rubbing my brother's back (he was about 16-17 at the time) and telling him that he should start studying with him (the MS) so that he didn't end up like his father. What arrogance. But I digress.
So sad, all of them.