I've had a wee bit of training in Suicide and suicide prevention with the Menninger Clinic in Topeka, Kansas; a few other places as well. I have no hard data to offer, though I will begin to look at some statistics. Anecdotally I'll say yes, the suicide rate for JW's is slightly elevated from that of the genral population. The are two possible contributing factors for this.
Anecdotally again, it seems the society attracts those who have emotional problems anyhow, that or the lifestyle creates or complicates these emotional problems. Just as importantly, the absence of belief in Hell, and therefore, no real consequences to suicide factor in on the decesion making process. This I know from my studies, one factor that restrains some from suicide is the idea of HELL. So, when faced with belief that suicide will mean one is not resurrected and only face oblivion, suicide is a more attractive option.
Let me get back with you on the stats, people actually track this stuff.
Yeru
YERUSALYIM
"Vanity! It's my favorite sin!"
[Al Pacino as Satan, in "DEVIL'S ADVOCATE"]