In an interview, Rowling had mentioned how Prisoner of Azkaban came from some of her darkest experiences and emotions. The dementors, creatures who suck out your soul, are her representation of depression, an illness which leaves your body intact, but extracts every bit of your personality and happiness from within. The movie itself describes them as “The dementors are amongst the foulest creatures to walk this earth. They feed on every good feeling, every happy memory until a person is left with absolutely nothing but his worst experiences.” The film was a pathway to more complicated, darker themes that the franchise will see henceforth.
In one very interesting scene, Alfonso Cuarón shows the boys inside their dormitory being goofy and kids, playing with one another, eating chocolates and laughing around, and then we get a wider shot showing how dementors lurk right outside their windows, surrounding the castle. It shows us how there are always things that are unknown to us, that can cause us sorrow and pain but sometimes, being in the present, oblivious to those outside unknown tragedies and fears can give us the simplest of joys.
One of the most genius plot points however, is how Rowling uses laughter as the weapon to scare away Boggarts (shape shifting creatures that take form of whatever scares you most). When Lupin is teaching the students to face off with the boggarts, Neville’s takes the shape of Professor Snape, Ron’s spiders, Parvati’s a snake and Harry’s boggart reshapes itself to resemble a dementor. What’s interesting to note here, is how for each of these students, their worst fears are something they have witnessed at Hogwarts, their beloved school. Neville has to study potions everyday with Professor Snape glowering over him, Ron had to hold his own against spiders and Parvati and the rest of the school shared the school with the basilisk serpent in The Chamber of Secrets and finally Harry, who before even getting to the school, had an unfortunate encounter with the Dementor. All of their literal worst fears are being realised at Hogwarts, a place that they call their homes. More importantly, they all deal with their fears just in order to continue loving their home.
In another remarkable instance introduced by Rowling, Lupin tells Harry that the dementors affect him more than others because he has seen and lived through harder circumstances than most people. Rowling uses her imagination to convey realities of life and in a way equip kids to deal with such emotions and consider them natural rather just avoid these complex feelings. Harry is thirteen in this part of the franchise, so he is officially a teen. I believe it is no accident that this happens to be the only story of the series where Voldemort is not shown even once. Where the real villain is depression. Oops, I meant dementors. And that is in service to the readers since teen suicides are one of the leading causes for death amongst adolescents.
Through her story, Rowling also shows us how important it is to take action rather than just waiting along for someone to come and rescue you. When Harry and Sirius are surrounded by the Dementors and Sirius is just about to get his soul sucked, Harry keeps imagining his father will come back from the dead and save him. However, with time (literally), he learns that he was the one who actually cast the spell. That the one who really saved him & Sirius, was Harry himself. She also teaches us the importance of treating animals with the same respect as us humans; first while introducing Buckbeak the Hippogriff to the plot, and later by urging Hermione & Harry to save him from being executed.
She teaches us that information can be misleading, especially when you do not know the whole truth. Like in Harry’s case, he first hears the gossip about Sirius being Voldemort’s biggest supporter who gave away James & Lily’s location and got them killed. This prompts Harry to resolve to kill Sirius and avenge his parents’ death. However, the story is false as we later find out. Not only does he learn his lesson to not make decisions half-informed, but he also saves Peter Pettigrew’s life by stopping Sirius and Lupin (James’ best friends) from becoming murderers – the very thing he earlier wanted to become by killing Sirius.
Lastly, the movie teaches us that sometimes in life, you will not be able to attain everything you set out to do. But that as long as you put in your full efforts, have the right intentions, amass the courage to take the right stands and learn from your mistakes, some good will come out of it. And that sometimes you have to settle for what life gives you and try to move on from the disappointment that you cast on yourself with all your high expectations.