Are psychological illnesses a sign of weakness in faith, is their treatment limited to ruqyah, and how do we differentiate between them and possession?

Psychological illnesses are a type of illness that can be treated with Ruqyah and medical psychological treatments, based on the Prophet's (peace be upon him) saying: "Treat yourselves, O servants of Allah, for Allah has not created a disease except that He has also created its cure or a remedy, except for one ailment." They asked: "O Messenger of Allah, what is it?" He said: "Old age."

The best treatment for psychological illnesses is faith in Allah, His decree, and His divine preordainments, and frequent supplication to Him. These illnesses do not necessarily indicate that the afflicted person has weak faith.

The difference between psychological illness and jinn possession: a person afflicted with jinn possession is completely taken over by the jinn and loses their mind entirely, whereas a person with a psychological illness may be suffering from a psychological problem due to an event that caused them a complex, and they may not completely lose their mind.