The mutism must also include impairment in social, academic, or occupational achievement or functioning to qualify as a diagnosis. Selective mutism is not present if it is related to lack of knowledge or comfort with the spoken language required of the situation or is due to embarrassment from a communication or developmental disorder. The symptoms cannot be better accounted for by another mental disorder or be caused by substances, medications, or medical illness.

Anxiety can be either a short-term "state" or a long-term "trait". Whereas trait anxiety represents worrying about future events, anxiety disorders are a group of mental disorders characterized by feelings of anxiety and fear.[10] Anxiety disorders are partly genetic but may also be due to drug use, including alcohol, caffeine, and benzodiazepines (which are often prescribed to treat anxiety), as well as withdrawal from drugs of abuse. They often occur with other mental disorders, particularly bipolar disorder, eating disorders, major depressive disorder, or certain personality disorders. Common treatment options include lifestyle changes, medication, and therapy. Metacognitive therapy seeks to diminish anxiety through reducing worry, which is seen[by whom?] as a consequence of metacognitive beliefs.[11]

People with panic disorder often worry about when the next attack will happen and actively try to prevent future attacks by avoiding places, situations, or behaviors they associate with panic attacks. Worry about panic attacks, and the effort spent trying to avoid attacks, cause significant problems in various areas of the person’s life, including the development of agoraphobia (see below).