Panic attacks are very sudden, and the symptoms can be more intense, but don't last as long as anxiety attacks. Symptoms of a panic attack can include accelerated heart rate, sweating, nausea, lightheadedness and more. On the other hand, an anxiety attack can cause difficulty concentrating, muscle tension and disturbed sleep. Anxiety attack s are usually less intense than panic attacks and can build up over a few days or even weeks. Both are treatable.
http://panicdisorder.about.com/od/understandingpanic/a/anxvspanic.htm
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