What makes a disorder in which intense anxiety or fear keeps person from functioning normally?

The disorder you're referring to is called an anxiety disorder. Anxiety disorders are a type of mental health condition characterized by intense anxiety or fear that can cause significant distress and interfere with a person's daily life. There are several types of anxiety disorders, including generalized anxiety disorder, social anxiety disorder, panic disorder, and phobias.

The symptoms of anxiety disorders can vary depending on the specific disorder but may include:

Persistent worry or fear

Feeling on edge or restless

Difficulty sleeping

Increased heart rate

Sweating or shaking

Difficulty concentrating

Irritability

Muscle tension

Headaches or stomachaches

Anxiety disorders can significantly impact a person's life, making it difficult to function normally in various areas, such as work, school, social interactions, and relationships. These disorders can also lead to physical health problems, such as headaches, stomachaches, and difficulty sleeping.

If you think you may be experiencing an anxiety disorder, it's important to seek professional help from a mental health professional, such as a psychologist or psychiatrist. Treatment options may include therapy, medication, or a combination of both. With proper treatment, most people with anxiety disorders can manage their symptoms and live fulfilling lives.