Everyone has fear, and is a necessary component of survival. When presented with danger in the environment, a person will have a physiological reaction where adrenaline is released into the bloodstream. Adrenaline is a fear-response hormone which causes several physical changes in the body, including increased heart rate, increased rate of breathing, and dilated pupils.
In addition, there is shunting of the blood flow from the digestive system and the skin to the skeletal muscles, which can be felt as having the "butterflies" in the stomach or having numbness and tingling sensations of the extremities. These physical changes allow the person to prepare to fight the danger, or to run from it, the so-called "fight-or-flight" response. The increased heart rate and breathing rate allows the blood to supply more oxygen to the skeletal muscles needed to fight or run, and the blood shunting to the skeletal muscles further aids this process. The dilated pupils allows for improved vision to assess the danger, and the brain becomes more alert and hypervigilant for danger, allowing one to scan their environment in order to deal with the external danger.
However, this fear response goes awry when one starts to anticipate danger, or starts to have thoughts about events which tend to overestimate the danger and underestimate one's coping abilities. In this situation, the fear response is heightened by one's thoughts about the event or future event, where the overestimation of danger and underestimating of one's coping leads to anxiety. And the body perceives fear and anxiety the same way, where the adrenaline response occurs with either. So when one has anxiety, the fight-or-flight response is activated, and serves no purpose as the danger is more in one's head- with their thoughts.
Anxiety becomes an anxiety disorder when the anxiety symptoms cause impairment of functioning in relationships and work / school, and the person has significant distress and unable to control the anxiety. The major anxiety disorders include generalized anxiety disorder, specific phobia, social phobia, panic disorder, post traumatic stress disorder, and obsessive compulsive disorder. Other anxiety disorders include substance induced anxiety disorder, anxiety due to a general medical condition, acute stress disorder, adjustment disorder with anxiety, separation anxiety disorder, and selective mutism. Each disorder is associated with a specific core anxiety symptom:
• Generalized anxiety disorder- generalized worries
• Specific phobia- phobia of an object or situation
• Social phobia- fear of social scrutiny
• Panic disorder- panic attacks
• Post traumatic stress disorder- flashbacks and nightmares of trauma
• Obsessive compulsive disorder- intrusive thoughts and ritualistic behaviors
Anxiety treatment involves psychotherapy, with cognitive behavioral therapy (CBT) having the most evidence for efficacy. CBT works on the premise that events or situations do not cause the anxiety; rather, the thoughts we have or meaning we give events causes the anxiety. CBT works by addressing the maladaptive thoughts, and work on more adaptive thoughts and suppressing and distancing one from the maladaptive thinking. In addition, CBT addresses the avoidant behaviors which serve to sustain the anxiety in the long term, but has anxiety relief in the short term. Other forms of psychotherapy include depth or insight oriented psychotherapy, which addresses the causes and the proximal determinants of the anxiety. If psychotherapy is not effective, or if the anxiety symptoms are severe, then pharmacotherapy with anxiety medications can be considered after a psychiatric assessment.