How can I rationalize with a delusional friend?

I have a friend who may or may not be schizophrenic. If he is, then it is mild - he is intelligent, functions perfectly fine both at work and socially. He is also a skeptical man like me; does not believe in religions, psychics, ufo’s and whatnot. However, he harbors one “conspiracy” theory which he refuses to let go of.

He had a mental breakdown last year and admitted himself into a hospital mental ward for about 2 weeks. He recieved medication - an antipsychotic and an antidepressant. Upon being released, he was convinced that the hosptial staff was conducting clandestine experiments at the expense of him and other patients. I have no idea what the exact purposes of these experiments were, and neither does he - but he maintains that it involved attempted brainwashing, sleep deprivation, and poisoning. He assumes it is somehow funded by government.

He goes on about how there are precedents for this sort of thing, namely MK-ULTRA of the 60’s. I ask him for evidence of any wrongdoing on the hospital’s part that would lead him to believe such things and he gives me weak testimonials about the behavior of the staff and the conversations of other patients. I can not convince him that his compromised mental condition might have misinterpreted what he experienced. I go on and on about the unlikelihood of such a thing, about how secret conspiracies are almost impossible to accomplish, and how the logistics of such an operation (financial risks, employees, red tape, etc) would prevent its existence unless a VERY lucrative benefit can be had by doing these experiments - and he still refuses to abandon this.

This is very frustrating - is there anything I can do or show him that will help destroy his silly idea?

Is this his only delusion? It sounds like you’ve done your best to disabuse him of his paranoid fantasy, you may have to just refrain from discussing it with him anymore and be thankful it’s not a lot worse.

I don’t know what else you can do either. When I was a kid, my mom had some wacky ideas too. She was able to function semi-normally other than that, and a lot of her wackier ideas have faded away. Most people would consider her “normal”.

Is your friend able to function in society (hold a job, go to school, whatever) without difficulty? Is he coping well otherwise?