Nope. Richard Dadd murdered his father believing him to be the Devil in disguise and was committed to Bedlam. After 20 years there, he was transferred to Broadmoor where he died. I've never read a diagnosis of his condition but it sounds very much like schizophrenia. Dadd was an amazing artist of such works as The Fairy Feller's Master Stroke.
Mad Martin was not an artist but a sometime Wesleyan preacher. He spent time in various asylums, including Bedlam. He was your average religious nut and pyromaniac.
_________________
Is God willing to prevent evil, but not able? Then he is not omnipotent.
Is he able, but not willing? Then he is malevolent.
Is he both able and willing? Then whence cometh evil?
Is he neither able nor willing? Then why call him God? [attr. Epicurus]