Is obsessive-compulsive disorder (OCD) regarding purification (istinja') and intention (niyyah), which has led to abandoning prayer and delaying ghusl (ritual bath) after menstruation due to obsessive thoughts about the intention, considered a valid excuse in Islamic law?

It is not permissible for a Muslim to abandon prayer or purification due to obsessive whispering (waswasa), and whoever does so has disobeyed Allah and obeyed Satan. The cure for waswasa is to ignore it and not indulge in it. Whoever has waswasa regarding istinja' (cleaning oneself after urinating or defecating) should sprinkle water on their private parts and the surrounding area after the flow of urine has stopped and istinja' has been performed, then disregard any wetness they may find. When praying, one should intend the specific prayer they are about to perform. When performing ghusl (ritual bath), a woman should intend purification from menstruation or post-natal bleeding, or the removal of major ritual impurity, while a man should intend ghusl from janaba (sexual impurity) or the removal of major ritual impurity.