Is it permissible for someone afflicted with obsessive-compulsive disorder (OCD), urinary incontinence, flatulence, and the slight expulsion of feces, to perform ablution (wudu) and pray without performing istinja’ for each of these matters before every prayer, and to suffice with istinja’ after the known calls of nature, in order to alleviate hardship and embarrassment?

The cure for obsessive thoughts (waswas) is to ignore them and pay no attention to them. If what you are experiencing is merely a waswasa, then disregard it and do not concern yourself with it. Do not conclude that something has exited (your body) unless you have absolute certainty. If you are absolutely certain that you suffer from fecal incontinence and that stool exits daily without your control, even once, then the Maliki jurists offer leniency in this matter and do not obligate istinja (definition) (washing after defecation). If the matter is extremely difficult for you, there is no blame upon you for adopting this madhhab (definition) (school of thought) until Allah cures you of the waswas; because a person afflicted with waswas is permitted to take the easiest of scholarly opinions to remove hardship and دفعاً للمشقة (repel difficulty).