Dr. Squires (Sir Ben Kingsley, left) offers guidance to Luke (Josh Peck) in The Wackness.

Sony Pictures Classics

It’s the summer of Forrest Gump and O.J.’s Bronco ride, of Biggie Smalls and big shiny bling. And in Jonathan Levine’s The Wackness, 1994 in New York City is also the summer when forlorn Luke Shapiro (Josh Peck), just graduated from high school and heading for his safety school in the fall, pushes an ice cream cart stocked with weed around town, dealing dope and tumbling into love with his psychiatrist’s step-daughter … his pot-smoking, “I could get you a hooker if you want” psychiatrist, that is.

A smart comedy that serves as both bittersweet coming-of-age tale and ’90s nostalgia piece, The Wackness has the feel of authenticity about it, even if some of its details (the ice cream cart, and the therapist’s bong, for two) seem a bit much.

In three acts (“June,” “July,” “August”), wistful and full of small surprises, Levine’s movie is about one of those memorable, life-turning teen romances. Luke, an outsider, a virgin, has never thought himself worthy enough to hang with a girl like Stephanie (Olivia Thirlby) — sexy, assured, aloof, cool. Even Luke’s shrink, Dr. Squires (a comically dissheveled Ben Kingsley), warns him off his step-daughter. But by midsummer, Luke and Stephanie seem to have taken their slight, jokey friendship to more serious places. Could the relationship be for real, or is Luke just being used, toyed with, set up for a hard fall?

The Wackness is deftly acted by Peck and Thirlby (Ellen Page’s best pal in Juno), with Kingsley in amusingly blotto form as the mumbly, melancholy analyst, Famke Janssen as his sad-eyed spouse, and Mary-Kate Olsen and Method Man in supporting roles. The soundtrack is full of vintage hip-hop, and so’s the screenplay: Luke, a nice Jewish kid whose parents appear on the brink of financial ruin, enters Dr. Squire’s wood-paneled office and announces, “I’m mad depressed, yo.”

The Wackness is imbued with a gentle irony, and writer/director Levine nicely counterpoints Luke’s “baby steps” towards adulthood and responsibility with Dr. Squire’s retreat into addled adolescence (his barroom canoodling with the neo-hippie chick played by Olsen is pretty creepy).

In the end, the movie is kind of blue, but kind of sweet, too.

****The Wackness

Starring: Josh Peck, Ben Kingsley, Famke Janssen, Olivia Thirlby, Mary-Kate Olsen.

Rated: R, contains sex, nudity, drugs, profanity, adult themes.