I am no expert on this issue (I am an electrical engineer by profession), but I have thought about this somewhat. I think that mentally ill people are attracted to Pentecostalism because of its irrationality and also because Pentecostalism condones insane and inappropriate behavior such as screaming, shouting, running, wailing, hopping, and other such things where insane people could fit right in and indulge their theatrics for attention. I think a large proportion of Pentecostal preachers are mentally ill also, given that the overwhelming majority of them are uneducated, and that there is no requirement for rigorous scholarship to become a Pentecostal “minister.” I understand that the level of education one has is not a determinant of mental illness, and that intelligent people can also be mentally ill; I am just speaking in general terms and general trends.
I also believe, based upon my studies, that Pentecostals and many Ex-Pentecostals who have not had appropriate therapy, suffer from Post Traumatic Stress Disorder. You will find many Pentecostals suffering PTSD symptoms as follows: stomach ulcers, depression, disassociation, troubled sleep, irritability and outbursts, difficulty concentrating or remembering, hypervigilance (like extreme paranoia), exaggerated startle responses, etc.
I encourage all who are interested in PTSD to get “The Post-Traumatic Stress Disorder Sourcebook,” by Glenn R. Schiraldi. It is available on Amazon and I have a copy, of which I have found great use.
The problem with the Ex-Pentecostal movement is that the field of psychology has not yet focused upon Pentecostalism; the closest material we can use at this stage of our history is the research done on cults – and, yes, some Pentecostal churches are cults. However, I have looked at PTSD symptoms, and also the symptoms of two other disorders that have been helpful in my studies: Disassociative disorder and De-personalization Disorder. You can Google either of these and find some useful information, and I think many here will see some parallel experiences with our Pentecostal experiences.