Final answer:
Anxiety disorders are the most common mental disorder, affecting approximately 18 percent of U.S. adults yearly, with various forms such as OCD, PTSD, and phobias.
Step-by-step explanation:
The most common mental disorder is anxiety disorders. According to data, almost 18 percent of U.S. adults may be affected by an anxiety disorder in a single year, with 28 percent potentially affected over a lifetime.
Anxiety disorders are characterized by persistent worries and fears that last for months and can significantly impact daily life. They include conditions such as obsessive-compulsive disorder (OCD), panic disorders, posttraumatic stress disorder (PTSD), and various phobias.
It's important to recognize that while everyone experiences anxiety from time to time, anxiety disorders are more severe and long-lasting. The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) is the standard for diagnosing these disorders.