A tiger walks the same worn groove along the edge of its exhibit like a broken record. A parrot methodically plucks out its ...

A new three-volume study, Abnormal Psychology Across the Ages, shows how far we have come in diagnosing and treating mental illness. In the Renaissance, the mentally ill were feared, shunned, and ...

Across captive settings, nonhuman primates may develop an array of abnormal behaviors including stereotypic and self-injurious behavior. Abnormal behavior can indicate a state of poor welfare, since ...

Many people seem to think calling a dog good, bad, happy, sad, aggressive, stubborn, bold, shy, vicious, alpha, pessimistic, optimistic, or abnormal can help us understand what they’re thinking and ...

Dear Doctors: My boyfriend says that lately I’ve been talking in my sleep and sometimes acting out my dreams. One time I actually hit him. He says it may be something called an REM sleep behavior ...

Example of repetitive behavior seen in mice. Some mice trace the same route through their cage over and over and over again. Abnormal repetitive behaviors in mice are strongly linked to multiple ...