These are just a few of the people I knew joined the Witnesses.
One was in high school when the cuban missile crisis was going on. She was terrified. The idea that God would prevent that from ultimately happening/or resurrection if it did, was what she needed. She is very childlike to this day and totally dependent on JW land.
My mother. Didn't want to grow old, remains childish and petty to this day. Depends on the WT to tell her what to do.
The real mentally ill/hampered:
A man who's father was mean, strict and crazy. He definitely has some problems and takes meds. Nice but ...
A born in who had an JW alcoholic father and a witch of a JW mother(who also had mental problems), has a personality disorder. She wouldn't leave because she believes she is anointed.
Old sister that I saw at a restaurant. She had a stack of napkins 6 inches high. Eat a bite of food, wipe mouth, throw napkin away. She also complained about others jewelry. The elders try to placate her so why would she leave?
And I believe that the WT's own twisted logic, encourages others to try it out also. An elder who instead of helping his wife with postpartum depression, convinced the elders to swoop in and take her child from her. Divorced her after he got her to sign away the properties that they both had bought. Dated while still divorced, got demoted when it was found out. Hid his money from the exwife. Hired illegals and transacted real estate by "giving" it to his father so that it would be hard to track it to him. (or something like that) When his sorry ass was finally hauled into court again to up his child support, one of the excuses he couldn't afford to pay more, was because he had bought his new wife a corvette and had to make payments.... I'm not even sure a classification of a sociopath would be correct since he doesn't feel remorse for any of it.
I also think the way the WT has articles on how the nice witnesses are always supposed to forgive the stubborn, mean, rude, witchy and gossipy people in the hall, teaches them to be a "doormat" and that causes mental distress too.