Doctors diagnose an anxiety disorder with a patient reports intense, excessive,and persistent worry and fear about everyday situations. Anxiety Disorderscan also include repeated episodes of sudden feelings of intense anxiety and fear, or terror known as Panic Attacks.Other symptoms can include, but are not limited to:

•Feeling Nervous, or Tense

•Increased Heart Rate

•Trouble Concentrating

•Trouble Sleeping

•Gastrointestinal Problems

•Sweating

•Trembling

•Feeling Weak, or Tired

•Feeling Self-Conscious

•Selective Mutism (consistent failure of children to speak in certain situations)

•Phobias (fearful of specific objects)

•Separation Anxiety(Also commonly seen in children)

•Social Anxiety(fear and avoidance of social situations)

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3683266/