This movie seems a little clunky around the edges, like not quite enough zaniness was thrown it when it should have been. But I mostly enjoyed it.
The storyline is more than a little bit preposterous, so no expectation of "something real" should be included in your viewing experience. Check your brain in at the door. It will not be needed and might be an impediment otherwise.
I quite enjoyed Clennon's performance as the real Dr. Baird. His role was spot on for giving Aykroyd's character a protagonist. What a putz the real Dr. Baird was.
And Matthau was quite good as the lead character's sidekick. Annoying at first, but ultimately lovable. Sort of. Kind of. Or at least something the use of a bar of soap and a lot of water would have been more than helpful.
Actually worth watching? If you're in the mood for a spoof on the psychiatric profession, sure, why not.