Summary of answer Jinn possession is proven by the consensus of the imams of Ahl al-Sunnah wal-Jama`ah. If a person who has this sickness is rational, then he has the choice and he will be brought to account for his words and actions. But if this sickness has overwhelmed him to the point that he has lost his mind and free will, then he is like one who is insane and is not accountable.