"The Couch Trip" is badly in need of Freudian slipcovers. Despite the estimable antics of Dan Aykroyd and Charles Grodin, it proves a threadbare farce -- a so-so shrink-rapper based on the overworked notion that psychiatrists -- not their patients -- are the crazy ones.

Grodin plays Dr. George Maitlin, a radio sex therapist who suffers a nervous breakdown. While he recuperates, his staff seeks a temporary replacement. Dr. Lawrence Baird, the head of a prison mental facility, seems a safe choice ... but unbeknownst to all and sundry, one of his escaped patients has assumed his identity.

Aykroyd is John Burns, alias Baird, a zany, off-center hacker imprisoned for computer fraud. When he intercepts Maitlin's call to Baird, he accepts the radio job, squirms out of his straitjacket and grabs a plane for L.A. There, his plain-spoken, four-letter advice to the lovelorn makes him the most popular psycho-babbler in the history of blab. He's a combination of the Greaseman, Dr. Ruth and Willard Scott.

Michael Ritchie, of "Fletch" fame, directs from a thrice-rewritten screenplay that's meant to work as a classic French-style bedroom comedy. But it's jerry-built, with all kinds of structural weaknesses and marginal characters -- especially Walter Matthau as Burns' sidekick, a revolting character who destroys the potentially interesting dynamics between Grodin and Aykroyd. There's even a part for Aykroyd's wife Donna Dixon, as a beautiful psychiatrist who pals around with the star but never becomes a love interest. Now that truly defies analysis.

The Couch Trip, at area theaters, is rated R for language.