What does Islam have to say about the huge spectrum of psychiatric disorders recognized today?
I'm not referring to severe disorders like schizophrenia, but more to the astonishing variety of mentally unwell people found everywhere in the world today.
Some phobias, compulsions, addictions, etc. seem to be so powerful that the disordered person genuinely seems to have little or no control over their actions sometimes. Think of an agoraphobic brother unable to leave the house to go to the masjid on Friday, an obsessive-compulsive who can't remove his shoes at all for fear of disease, a nicotine addict or bulimic unable to fast during Ramazan due to their uncontrollable compulsions, a woman who was sexually abused as a child who finds herself unable to be intimate with her husband, the narcissist incapable of being genuinely humble.
How do the scholars view such people? Are their mental disorders a sign of a diseased heart or over-indulged nafs? Or, on the contrary, are these diseases actually gifts from Allah, to test them on a daily or hourly basis, and to make them struggle maybe a thousand times harder than "healthy" people to carry out quite simple fardh or to avoid haram?
Are syndromes like "sex addiction" genuine illnesses, and a genuine handicap, a bit like an amputee who manages to perform salah against the odds? Or are they the person's own fault, some kind of weakness?
I wondered about this long before I became a Muslim, but I concluded that various "experts" would never be able to agree on whether some people were "born that way", or naturally weak, or developed unhealthy ways of thinking due to environment, or chemical imbalance, or any of the above. I know a few people who say "it's not my fault, it's because I have X-ism or I'm a Y-ic" or whatever. Is it really beyond their power to stop themselves from washing their hands 27 times with disinfectant soap every time they touch another person, for example? If so, do the scholars have any opinions as to why a person would be given such an affliction? If not, then are all mental "syndromes" and "disorders" nothing more than over-indulged nafs?