"What About Bob?" is rather thin comedy material, and it's not particularly original — everything from "The Dream Team" to "The Great Outdoors" came to mind while watching it.

But there's no question that the engaging performances of Bill Murray and Richard Dreyfuss manage to breathe a great deal of life into the proceedings, and before it starts to run out of steam toward the end, the film provides an awful lot of laughs.

Murray plays a pesky psychiatric patient, a man with more phobias than "Sybil" had personalities, who tends to latch on to his therapist. This has driven his psychiatrist out of the business, but not before he dumps off Murray on a colleague — a best-selling author played by Dreyfuss.

Murray is afraid of everything, from everyday germs to elevators, and though he recognizes his illness he can't seem to do anything about it. Dreyfuss prides himself on being Mr. Cool. "I don't get angry," he says at one point, but he also doesn't know how to be warm and tender with his family.

During Murray's introductory session with him, Dreyfuss announces he's going away for a month's vacation, and Murray is already so attached to him that he's devastated. Of course, it isn't long before he tracks down Dreyfuss at his New Hampshire summer home and begins endearing himself to the family and just about everyone else in the small vacation town — everyone except Dreyfuss, that is.

You can probably predict the rest — as Murray drives Dreyfuss crazy he also gives his family members the kind of nuturing Dreyfuss is unable to provide, while the tension between them escalates.

The main thing that makes this work is Murray being obnoxious without losing his charm. This is Bill Murray at his most affable, and despite the things he does, the audience never loses its connection with him. At the same time, Dreyfuss manages to react wildly to Murray without ever carrying it too far. Though his character is by far the least sympathetic in the film, Dreyfuss manages to make us care about him and understand why Murray is getting under his skin.

There are some good supporting players here, including Julie Hagerty ("Airplane!") as Dreyfuss' wife and Charlie Korsmo ("Dick Tracy") as their young son.

It's unfortunate that all of this doesn't quite hold up to the finale, and the ending feels flat and rushed. But this is farce, after all, and it's the laugh quotient that counts most.

"What About Bob?" is funny enough to get away with being imperfect.

It's rated PG for a couple of profanities and some vulgarities, along with the expected comic violence.