Principles for the protection of persons with mental illness and the improvement of mental health care, GA Resolution 46/119, Principle 4.2, 4.3, 13.1 (d)
Determination of mental illness
2. A determination of mental illness shall never be made on the basis of political, economic or social status, or membership of a cultural, racial or religious group, or any other reason not directly relevant to mental health status.
3. Family or professional conflict, or non-conformity with moral, social, cultural or political values or religious beliefs prevailing in a person’s community, shall never be a determining factor in diagnosing mental illness.
Rights and conditions in mental health facilities
1. Every patient in a mental health facility shall, in particular, have the right to full respect for his or her:
(d) Freedom of religion or belief.