Assalaamu alaikum,
A lady who has the intention of going to a therapist due to her anxieties, is worried that she may be asked about very personal episodes from her past which will reveal her sins. These sins have a veil over them at the moment alhamdulillah, not a great many people are aware of them, but she knows that in order to tackle her mental problems she may have to address these issues. She asks, what should she do? Is she allowed to reveal her past sins to the therapist?
Jazak Allah khair

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

It is not permissible for a Muslim to inform anyone about his/her past sins; rather, he/she is obliged to repent to Allaah and conceal his/her sins. Indeed, we have already clarified this in Fataawa 83573 and 84052, so please refer to them. This is the principle, however, if there is a preponderant benefit that requires informing about some of those sins, and there is no way to achieve this benefit except by this means and it is absolutely confirmed that informing about it is beneficial, then it appears that it is permissible to inform about it but it is an obligation to restrict this to what achieves the benefit only in regard to the quantity of the information and the people to whom it should be divulged.

Moreover, she is permitted to only inform the female psychologist –for example –according to what the necessary situation requires, because necessity is measured in accordance with its true proportions.

Nonetheless, before resorting to this means, we advise this sister to supplicate Allaah and mention Him as much as possible, and perform Ruqyah on herself, as clarified in Fatwa 88705. It might be that Allaah may facilitate for her the treatment without resorting to that means. Then, if she is in need to go to a psychologist, then she should consult a person who is trustworthy in his religion and who is experienced in his profession.

Finally, it should be mentioned that in treating a female patient, a male doctor comes in priority over a non-Muslim male doctor, and a female doctor comes in priority over a male doctor. 

Allaah Knows best.