Answer -

Our contemporary scholars have ruled that the issue of hypnotherapy has something to do with using the help of the jinn, and based on that we must note the following two points: 

1 – It is not permissible to seek the help of the jinn or any other creatures in trying to find out matters of the unseen, whether that is by calling upon them, trying to please them or any other method. Rather that is shirk because this is a kind of worship, and Allaah has taught His slaves to worship Him alone and say, “You (Alone) we worship, and You (Alone) we ask for help (for each and everything)” [al-Faatihah 1:5 – interpretation of the meaning]. And it was proven that the Prophet (peace and blessings of Allaah be upon him) said to Ibn ‘Abbaas: “If you ask, then ask of Allaah, and if you seek help, then seek help from Allaah.” (Narrated by al-Tirmidhi, 2516). 

2 – Hypnotism is a kind of fortune-telling or magic whereby the hypnotist uses the jinn to overpower the subject and then speak through his tongue and give him strength to do things by means of controlling his faculties. This is if the jinni is sincere towards the hypnotist and obeys him in return for the things by means of which the hypnotist draws close to him. So the jinni makes the subject obey the wishes of the hypnotist to do things or tell him things, through the help of the jinni. Thus using hypnotism as a means of finding out where stolen goods are hidden, or where a lost item is, or as a means of treating disease or of doing anything else is not permissible. Rather it is shirk, for the reasons stated above, and because it implies turning to someone other than Allaah and goes beyond the ordinary means which Allaah has created for His creatures and permitted them to use.

Al-Lajnah al-Daa’imah li’l-Iftaa’, 1/74. Silsilat al-Fataawa al-Shar’iyyah