In this counseling answer:
• Speak with your imam, if possible, about a medical exemption.
• Do not discontinue any medication.
I am happy to hear you are seeing a therapist and that you feel you are getting the proper treatment and are on your way to stabilization. Counseling is the primary treatment for a mental disorder such as Depersonalization Disorder as it utilizes techniques to help you understand and resolve these feelings. Medications such as Pozac and/or Klonopin are sometimes used as well to help with any feelings of anxiety or depression. I am not sure if you are on medication or not, but if you are, it is very important that you do not discontinue any medication that was prescribed to you.
You may have other conditions which you did not mention such as low blood sugar which may exacerbate the symptoms and feelings of depersonalization; therefore, it is critical that you eat. There are many people who have various disorders and cannot fast in Ramadan. They are medically exempted. I am not an Islamic Scholar, but I do know that some of my clients are exempted from fasting due to mental health issues which require daily medication, or, as in your case, the symptoms get worse if they do not eat.
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I would kindly suggest that you speak with your imam, if possible, about a medical exemption. Anything that interferes or causes harm to your body or mental health treatment during Ramadan due to an illness, physical condition, or mental health condition is usually exempted. In your case, part of your treatment-recovery and stabilization centers around eating. Allah (swt) is most merciful.
I would kindly suggest that you do follow the prescribed Islamic guidelines for those who cannot fast which is feeding, providing food for others to make up your fast. Allah (swt) in His mercy does not want us to compromise an already sick body or unstable mind such as in the case of Depersonalization Disorder. Allah (swt) has, therefore, in His mercy and kindness provided another way for those who cannot fast to be in compliance with His commands.
You may find much joy in providing food for others, whether you have cooked or bought it, or in just seeing the joy on their faces when you give it to them. There are many Muslims who do not have enough food during Ramadan to sustain them at Suhoor and Iftar. Your provided food is a blessing, indeed.
Please, check with your Imam or ask your counselor if she knows of a Muslim colleague who has the credentials or experience in this to give you a final answer. Based on your brief question and mental health needs, I believe you are exempt, but please check if you can.
I wish you many blessings during Ramadan. It is a time in which you may continue recovery from your status of Depersonalization Disorder as Allah (swt) knows your heart and your intention and your desire to please Him. Please do let us know how you are doing. You are in our prayers.
Disclaimer: The conceptualization and recommendations stated in this response are very general and purely based on the limited information provided in the question. In no event shall AboutIslam, its counselors or employees be held liable for any damages that may arise from your decision in the use of our services.