I haven't read it, but I can relate to the idea that many JWs have a lot of repressed emotions that are making them sick.
It's not acceptable in this religion to say you aren't 100% happy, because YOU HAVE THE TRUTH, how could you not be happy? If you do have problems, they can all be solved by more prayer, study, meetings and service. It doesn't take a psychologist to know that this is patently untrue and causes more people to feel worse because it makes then feel like a failure. The fact is that it is not acceptable to express negative emotions, especially for women.
Anger and rage are expressed in a lot of different ways. Some people become depressed, some use alcohol or drugs to band-aid the problem, which only creates more problems. Some use illicit sex, other becomes workaholics. Some turn their negative emotions inwards and become sick. It becomes a negative spiral, becauseof the black and white thinking of the religion, as any of these things are seen as a moral failing.
I read a story on the Jehovah's Witness suicide page that broke my heart. A young mother suffered from depression. The elders counseled her to be more diligent in meeting attendance and service. She signed up to auxiliary pioneer. Towards the end of the month she killed herself, she only had ten hours for the month, far short of what was needed.