Such limiting behaviors can range from obsessive-compulsive disorder (OCD ... One habit that can fall into either category is nail biting. Start the day smarter. Get all the news you need in ...

These include pulling, picking, biting, or scraping one's hair, skin, or nails ... They frequently cause extreme emotional distress, particularly if the disorder is undiagnosed or kept secret.

It's "nail-biting work", and it feels as if the pair are in "extreme danger" for much of the film: a "hidden camera could be detected or a slip of the tongue could expose them" at any moment.

Self injurious behaviors were associated with dysregulation, sensory hypersensitivity, age, sex, IQ, and language level in youth with autism.