If you enjoyed “Catcher in the Rye” and take to Philip Roth’s poignant and comical explorations of young, confused heroes, you are bound to enjoy and admire “The Wackness,” the audience favorite of this year’s Sundance Film Festival.

Can you resist a really good film about first love? How about a wacky, offbeat comedy with poignant undertones? Set in Manhattan in the summer of ’93, it’s about a drug dealer and a psychiatrist to whom he supplies weed. The exchange is not cash but a session, because Luke Shapiro, played by Josh Peck, wants to lose his virginity, maybe to a girl he can fall in love with.

So Jeff Squires, the flamboyant doc, played with mischievous turbulence by Ben Kingsley, advises the bashful kid to be bold and stick that tongue right into a girl’s mouth and kiss the heck out of her. So who does Luke fall for and succeed with but the psychiatrist’s stepdaughter, Stephanie, played wonderfully by Olivia Thirlby, who had the role of Juno’s best friend in “Juno.”

Summer fling?

Taken aback, the doc dispenses some pretty sage advice, as he tells Shapiro that for Stephanie, who will be entering a top-notch school in the fall, this is a summer fling. Oh, no. Can this mean that the kid headed for his third-choice college is going to have his heart broken big time?

Alas, there’s more to this smart, lighthearted comedy. Shapiro and Dr. Squires bond; they hang together, and when the recent high school graduate wheels his ice cream push cart filled with marijuana around the neighborhoods, Dr. Squires joins him. One night, they party with a few of Shapiro’s customers — one of them named Union, a real dopehead played convincingly by Mary Kate Olsen. Yep, that Mary Kate Olsen. Watch as she and Dr. Squires make out in a phone booth.

For all its wackiness, “The Wackness” serves up some touching moments and truly memorable scenes. The unabashed old hippie played by Kingsley really has something to him; he’s no slouch, just a New York guy stuck in a marriage that has seen its day. By the time it’s over, Shapiro becomes his shrink and confidant. The two guys from different generations become buddies.

Meanwhile, we get to peek into the soul of Stephanie, and if you want to get serious for a moment, you may conclude she is in for a hard life. If it’s foolish to fall in love and commit to permanence right after high school, maybe the time comes when you’re fickle and too jaded to find or keep real love at all. There are signs that Stephanie may already be turning into her mother, played by Famke Jansen.

Likable characters

In case I have not been clear, I really liked “The Wackness.” I liked the cockeyed story, I liked and believed in the characters, and I could relate to its views on love and pain and wackness — that is, the irrational ways in which life takes on illogical but universally recognizable directions.

Kingsley could have turned this into an ego trip, but in creating a colorful character, he practices restraint. Peck is excellent as the vulnerable hero, innocent despite his illegal, profitable pastime. Thirlby comes into her own, and just about everything about this comedy shows flashes of wisdom and affectionate endearment.