When watching the fifth film in the Harry Potter series, “Harry Potter and the Order of the Phoenix,” it might be useful to have a checklist for adolescent depression on hand. In this installment, Harry Potter exhibits frequent sadness (dead parents: check), a sense of hopelessness (his archenemy, Voldemort, is overwhelmingly evil: check), social isolation (his mentor, Dumbledore, is ignoring him: check), feelings of guilt (Cedric Diggory died in his arms at the conclusion of the previous movie: check), increased anger (fighting with Ron Weasley again: check), and an inability to enjoy previously favorite activities (not a game of Quidditch to be found: check). Perhaps a more appropriate title would be “Harry Potter and the Prescription for Prozac.”

While fans may decry the absence of this subplot or that minor character from J.K. Rowling’s 870-page book, what’s most noticeably missing in this movie is sunlight. From the opening scene of a scorching summer day quickly doused by an icy typhoon, the weather forecast is generally dreary, full of dank fog, pounding rain, and moonless nights. More than once you expect even the scenery to crawl back into bed and pull the covers up over its head. This might just be the most morbid summer blockbuster ever made.

It’s dark days for the Hogwarts gang when Harry (Daniel Radcliffe) uses magic to protect himself from a Dementor attack while on summer holiday with his piggish Aunt and Uncle, violating the rule against waggling his wand in front of Muggles. After Harry is expelled from Hogwarts for this indiscretion, an inquisitorial hearing before the Ministry of Magic sees him acquitted, but it sets the tone for the rest of the movie: pain, suffering, and threats of torture.

The Ministry of Magic spends the film vigorously denying the return of the evil, nose-less Lord Voldemort (Ralph Fiennes) and Hogwarts’s headmaster, Albus Dumbledore (Michael Gambon), finds himself ostracized as an alarmist for saying otherwise. Disgrace and resignation follow, and he’s replaced as Hogwarts headmaster by the latest Professor of Defense Against the Dark Arts, Dolores Umbridge (Imelda Staunton), a pink-clad fascist who believes in order, fussy collectibles, and carving helpful homilies into the flesh of disobedient students.

With war on the horizon and only the top-secret and understaffed Order of the Phoenix standing in the path of Voldemort, Harry and his classmates organize a resistance cell and teach themselves how to fight back against the dark arts. It’s after one of these illicit training sessions that Harry enjoys his first kiss with Cho Chang (Katie Leung), although “enjoy” might be too strong a word. Throughout this film, Harry doesn’t do much more than endure, constantly tormented by his growing bond with Voldemort, restlessly dreaming of beckoning hands and slithering snakes. He’s so quick to anger, so persecuted, and so isolated that he seems less like a potentially powerful wizard than a potential school shooter. The plot, which manages to condense the longest book in Ms. Rowling’s series into the shortest of the Potter films, whizzes by like the Golden Snitch in a Quidditch match, and the result is a movie that feels like one long nightmare, punctuated by swirling headlines, close-up shots of Harry moaning in his sleep, and the repeated image of the snarling caretaker, Argus Filch (David Bradley), climbing a teetering, 100-foot stepladder to nail Orwellian proclamations to a stone wall.

Director David Yates is an award-winning British television director with series such as the twisty “State of Play” and “Sex Traffic” to his credit, but someone still needs to prove to me that “David Yates” isn’t a pseudonym for Terry Gilliam. With its byzantine bureaucracies, its infinite filing shelves in the Department of Mysteries, and its general tone of tweedy despair, the closest spiritual sibling to this film is Mr. Gilliam’s dystopian epic, “Brazil.”

Still, no other current movie franchise is as reliably entertaining as the “Harry Potter” series. The production values are always posh, the writing is practically Shakespearean when compared with other summer blockbusters, and the only let-down is the special effects. The monsters and flying broomsticks are okay, but the “Harry Potter” films usually climax with a wizard’s duel, which consists of two men waving sticks at each other while colored lights fly back and forth. It may read great on the page, but it’s dead on arrival as cinema.

The real special effects, however, are the characters. This franchise has become something of an employment agency for British actors of a certain age, and in exchange for an enormous paycheck, they lend the movies their dignity. What Mr. Gambon, Brenda Gleeson, Fiona Shaw, Maggie Smith, and Julie Walters are doing is hardly acting, but their ferociously sincere commitment to the material is what sells these films. Alan Rickman’s cold, clammy Severus Snape has become far more interesting in the movies than he is in the books, and he almost steals “Order of the Phoenix.”

But that honor ultimately goes to an amateur, Evanna Lynch, playing an eerie albino named Luna Lovegood. A fan of the Potter books who believed that no one could portray her favorite character as well as she could, Ms. Lynch beat out 15,000 other actors for the role and with her distracted spookiness and love of pudding, she’s the brightest spot in the film.

Ms. Rowling’s world of houseelves and Triwizard tournaments sounds like the purest whimsy, but she never promised she was writing a fun series for young children. As the dead bodies and betrayals pile up, as the cast swells with orphans who have axes to grind and disappointment becomes the order of the day, it appears that she’s forcing the audience to experience growing up along with her characters, book by book and movie by movie. Already we miss the sun-speckled wonder of the first two films and, as well-made as they are, we can’t wait for these middle, stormily adolescent installments to end because they’re almost unbearably bleak.

Fortunately, the one thing the viewer knows that Harry and his friends don’t is that adolescence does end and eventually the sun comes out from behind the clouds. Let’s hope that, with two movies to go, the filmmakers remember that as well. Another movie as heavy as “Harry Potter and the Order of the Phoenix” and the underage Harry fans are going to need a stiff drink.