An anxiety disorder is a mental illness that produces fear, worry and a constant feeling of being overwhelmed, according to WebMD. Common anxiety disorders include social anxiety disorder, specific phobias and generalized anxiety disorder.
Although many people feel nervous or anxious at times when faced with stressful decisions or situations, such as life changes or tragedy, people with anxiety disorders are often crippled by the stress and unable to function or lead a normal life, explains WebMD.
Common symptoms of an anxiety disorder can include feelings of uneasiness, fear or panic; an inability to stay calm or stay still; and problems sleeping, notes WebMD. Physical symptoms such as cold or sweaty feet and hands, heart palpitations, shortness of breath, nausea and dizziness may occur when a panic attack or generalized anxiety sets in. In addition, people with anxiety disorders may experience dry mouth, muscle tension, dizziness and tingling or numbness in the hands or feet.
As of 2015, the exact cause of anxiety disorders is still unknown but can be contributed or magnified by factors such as environmental stress and brain function, states WebMD. Anxiety disorders, just like many mental illnesses, are not a reflection of character flaws or personal weaknesses.