Nick Robinson stars as the title character in “Being Charlie.” ( Photo by Fred Hayes aPALADIN Release)

Directed by Rob Reiner from a screenplay written by his son Nick Reiner and Matt Elisofon, “Being Charlie” is an unflinching look at addiction, inspired by the younger Reiner’s own struggles with drugs and revolving-door rehab. To their credit, the filmmakers do little to flatter the titular fictional protagonist, a spoiled brat with a foul mouth and bad attitude, except in the casting of an exceptionally appealing young performer in Nick Robinson (“Jurassic World” and “The Kings of Summer”).

Robinson, whose character is just turning 18 — in rehab — as the film opens, underplays his natural charm. Charlie, the embittered son of an emotionally distant actor turned politician (Cary Elwes), is so unpleasant to be around — even if only for 97 minutes — that I found myself wishing that the film were a bit more flinching in its portrayal.

Charlie, an aspiring stand-up comedian, comes across as a caustic bundle of ingratitude and casual cruelty, lobbing nasty jokes about a woman’s weight during a talent show organized at his second rehab facility — yes, he hadn’t lasted long on the wagon — while providing viewers with scant insight into the source of his seething resentment.

If every child of an imperfect parent turned to heroin for solace, there would be a halfway house on every street corner.

It has been said that an addict must hit rock bottom before he’s capable of sincerely seeking help. The film confirms this, charting Charlie’s long, downward spiral of misery before getting to that nadir, with a splat. The only reason Charlie is back in rehab is that his father has threatened him with homelessness and criminal prosecution — for breaking a window at the first rehab facility — if he doesn’t comply. Left to his own devices, Charlie would be hanging out with his high school pal Adam (Devon Bostick), a fellow substance abuser. In fact, once Charlie gets out of rehab, Part 2, and has graduated from his “sober-living” halfway house, he and Adam do get together, unwisely.

Want more bad news? Charlie disregards the advice of his addiction counselor (Common) and begins a romantic relationship with Eva (Morgan Saylor), another fellow addict he has become smitten with while trying to get clean. She has even less impulse control than Charlie and Adam do.

None of this bodes well, either for Charlie or for the film, which telegraphs its intentions — and final destination — well before it ends. There’s something admirable about the fact that “Being Charlie” exists at all. It’s a testament to Nick Reiner’s survival. That doesn’t mean it’s a great movie.

Put another way, “Charlie” is a cautionary tale. You may, I suppose, consider this review another one.

Unrated. At Landmark’s West End Cinema. Contains drug use, including an overdose, crude language, sexual dialogue, nudity, sensuality, violence and smoking. 97 minutes.