Praise be to Allah, and may peace and blessings be upon the Messenger of Allah.
First: Jinn possession of human beings is established according to Ahl al-Sunnah wal-Jama'ah (the Sunni scholars). Shaykh al-Islam Ibn Taymiyyah, may Allah have mercy on him, stated that a jinni entering a human body is an established matter, and it was reported that the leading Sunni scholars agreed on this.
Second: Jinn possession is not exclusive to Muslims. It can happen to both Muslims and non-Muslims, because the circumstances that may lead to such possession are not limited to people of a particular religion.
Ibn Taymiyyah, may Allah have mercy on him, mentioned three reasons why jinn may possess a human being:
A jinni may admire or love a person and consequently possess them.
A person may harm the jinn, such as by pouring hot water on them or unknowingly killing some of them.
It may happen as a form of mischief and harm.
These circumstances can occur with both Muslims and non-Muslims.
Furthermore, the fact that discussions about jinn possession among non-Muslims are not widespread does not mean that it never happens. Some non-Muslims may not believe in the existence of jinn at all, or they may interpret what happens to them through medical or material explanations.
Third: Not every condition thought to be jinn possession is actually caused by jinn. Some cases may result from physical or psychological illnesses. Therefore, medical treatment should not be neglected, and people should avoid charlatans and impostors.
A Muslim should maintain regular remembrance of Allah and perform Islamic ruqyah, such as reciting Surah Al-Fatihah, Ayat Al-Kursi, and the two protective chapters (Al-Falaq and An-Nas). A person may perform ruqyah for themselves and their family. If they need a ruqyah practitioner, they should seek someone known for righteousness and adherence to Islamic ruqyah.
Conclusion: Jinn possession is not exclusive to Muslims. It may affect both Muslims and non-Muslims. However, it is incorrect to attribute every illness or psychological disorder to jinn possession, as such conditions may have medical or psychological causes requiring appropriate treatment.
And Allah knows best.