Panic Attacks
Definition: Panic Attacks are comprised of discrete period of overwhelming anxiety and fear. Panic attacks come abruptly and for no apparent reason. After the onset of the panic attack a person will experience both physical and mental discomfort. These symptoms both physical and mental peak in about ten minutes. Panic attacks subside as abruptly as they begin, lasting anywhere from seconds to several hours. Most Panic Attacks do however pass in a few minutes and only in rare cases last several hours. The frequently of these attacks may vary from several times a day to only once or twice a year. After the onset of the first attack many people develop anticipatory anxiety.
Not due to a substance, general medical condition, or other disorder.
Discrete period of intense fear and physical / mental discomfort with four or more of the following:

Generalized Anxiety Disoder
Definition: Generalized Anxiety Disorder (GAD) is characterized by free-floating anxiety that seems to be a constant feature of daily existence. GAD can range from mild nervousness to a continuous feeling of dread. There may be somatic symptoms, muscle tension, muscle aches, or shaky feelings. GAD is frequently related to another disorder. ( E.g., Dysthymic, Major Depression, Panic Disorder, Social Phobia, Specific Phobia, or Substance Abuse ) Irritable Bowel Syndrome and headaches may accompany GAD.
Given the stresses of modern life, it is normal to experience occasional anxiety. However, people with Generalized Anxiety Disorder, or GAD, suffer from persistent worry and tension that is much worse than the anxiety most people experience from time to time. The high level or chronic state of anxiety associated with GAD can make ordinary activities difficult or even impossible.
The main symptom of GAD is an exaggerated or unfounded state of worry and anxiety, often about such matters as health, money, family, or work. Although people with GAD may realize that their anxiety is excessive or unwarranted, they are unable to simply "snap out of it" - for them, the mere thought of getting through the day can provoke anxiety.
The persistent worry characteristic of GAD is hard to control, and interferes with daily life. Many GAD sufferers seem unable to relax, and may startle easily. In addition, GAD is often accompanied by physical symptoms, such as fatigue, headaches, and muscle tension.
GAD does not appear suddenly; it develops over time. To be diagnosed with GAD, you must have had anxiety more days than not for at least 6 months.
Not due to a substance, general medical condition, or other disorder.
For at least six months the person had more days full of anxiety and apprehension then not. There is difficult dealing with the anxiety and apprehension. Have three or more of the following associated with the anxiety and apprehension:

Anxiety and apprehension not associated with another disorder (such as drug abuse, general medical condition, medication, OCD, PSTD, Separation Anxiety Disorder, Social Phobia, Specific Phobia). Must be impairment in important areas of functioning, such as work or social life.