I read through some of this post and I can agree with Jazzbo in that we must make sure of the research and not just accept it because "it agrees with our viewpoint." But I will say this based on my own personal experiences.
Someone asked if they were similar reseach conducted on people in fundamentalist religions. If anyone has been reading my posts, they will know that although I was never a Jehovah's Witness personally my first experience with church (that counted I guess) was within a fundamentalist church. The preacher would regularly and dogmatically preach about things that had little to no basis in the Bible and I would feel like even though my salvation is supposed to be guaranteed by Christ, I still wasn't doing enough to please God and ensure that I was good enough for Him (sound familiar?). Many days I would come home from church feeling depressed and even a bit suicidal because I would be made to feel low because the preacher would give a sermon that I felt he was directing at me personally (sound familiar?). Legalism was the name of the game and it would often make me wonder how a loving God would say on the one hand, "You are my son due to the my free gift through Christ." and later say, "You are doing these things I hate and you are not good enough for Me." (SOUND FAMILIAR?)
Did my 'depression' happen because of the religion? I can't say because throughout my childhood, I have always had to deal with life's ups and downs and sometimes I did not cope well and sometimes I did. I will say that it certainly did not help my mood at all and going there was not always the uplifting thing that people expect within their home church. I mean, the church is suppose to be our santuary where we can go to get some spiritual uplifting. I don't expect the church to be able to provide it on a 100% basis every time but if someone regularly feels down and depressed even though that individual is devout, something's wrong.
It wasn't until I began fading from that church and attending college before I began feeling better about myself. Consequently, the feeling down all of the time faded along with it. Eventually, I began to see those churches for what they were and decided that I was better off without church. However, God still loved me and a few years later when I went through another down point in my life, He stepped in and lifted me up and this time I stayed away from the Independent Fundamental Baptist churches. In fact, I started attending a Church of God (a church that my IFB pastor said was preaching false doctrines due to their tongue speaking). I guess it was my little 'rebellion' against the IFB churches.
After graduating from college I met my wife who I learned was a witness. I did not know a lot about them at the time for I just thought they were a bunch of well dressed people who go door to door, not believing in Hell, not celebrating Christmas, and called God Jehovah. One thing I noted about her and her sister early on is that they took medication for their head. She was (and still is) on Paxil but I did not link it to the religion immediately. She just told me that she had panic attacks and feared large crowds. But her views concerning God astounded me to say the least. Rather than a loving God who did not want anyone to perish and even sent His own Son to redeem us, she talked about Him like He was this God who is waiting for people to do wrong so He could destroy them. Rather than a loving God who judges sinners not because He does not love them but because these sinners choose to reject Him and He therefore has no choice to but judge them on their works and allow them to die in their sins, she portrays Him as a God who is looking to take away His gift of everlasting life at the first opportunity when one of His children commit a wrong act.
Her God is depressing. How can the Jehovah's Witnesses deny Hell claiming that a loving God will not permit His creation to suffer for an eternity, yet portray Him as an unloving being looking to kill His children at the first opportunity? Keep studying, keep attending meetings, keep going out in field service, keep pleasing the elders, keep serving Jehovah, don't play sports, don't go to the YMCA, don't associate with worldly people, and don't even think of celebrating the holidays or your birthday. If someone is disfellowshipped, don't you even think of being that person's friend for Jehovah will be very displeased with you and cut you off from His people too.
My wife told me that if she knew she did not have to 'follow all of these rules' to obtain everlasting life, she wouldn't. She even told this to the book study elder and his wife and his wife felt the same way. I've tried telling her about the free gift from Christ Jesus but she doesn't beleive it is that simple. 'Faith without works is dead' is her favorite response. I guess she will always be on Paxil.
So even if Dr. Bergman's research is not the most 'credible' research concerning people in legalistic, rules based, religions like the Jehovah's Witnesses, I will certainly say based on my own personal experience that I think he is really onto something.