Which of the following is NOT considered a prominent category of mental illness?

Insomnia is not typically classified as a prominent category of mental illness. It is primarily considered a sleep disorder that can affect one's ability to fall asleep, stay asleep, or achieve restorative sleep. While insomnia can be related to various mental health issues, such as anxiety or depression, it does not stand alone as a major category of mental illness like the others listed.

In contrast, mood disorders encompass conditions such as major depressive disorder and bipolar disorder, while anxiety disorders include generalized anxiety disorder and panic disorder. Eating disorders, such as anorexia nervosa and bulimia, are recognized as significant and often debilitating mental health conditions. Dementias, including Alzheimer’s disease, signify a category that affects cognitive function and memory, while schizophrenia and other psychotic disorders involve a disconnection with reality, impacting an individual's thought processes and perceptions.

Thus, insomnia is more a symptom that may arise within the context of various mental health challenges rather than a distinct, recognized category of mental illness.