Without treatment, panic attacks tend to occur repeatedly for months or years. While they typically begin in young adulthood, the symptoms may arise earlier or later in life in some people. Complications, which are symptoms that can develop as a result of continued panic attacks and develop into other mental illnesses, may include specific irrational fears (phobias), especially of leaving home (agoraphobia) and avoidance of social situations. Other possible complications can include depression, work or school problems, suicidal thoughts or actions, financial problems, and alcohol or other substance abuse. For children and adolescents, panic disorder can even interfere with normal development. Panic disorder and other anxiety disorders also predispose sufferers to developing heart or gastrointestinal diseases, high blood pressure or diabetes, having more severe symptoms if they have a respiratory disease, and of dying prematurely.
An evolutionary psychology explanation is that increased anxiety serves the purpose of increased vigilance regarding potential threats in the environment as well as increased tendency to take proactive actions regarding such possible threats. This may cause false positive reactions but an individual suffering from anxiety may also avoid real threats. This may explain why anxious people are less likely to die due to accidents.
People with panic disorder often worry about when the next attack will happen and actively try to prevent future attacks by avoiding places, situations, or behaviors they associate with panic attacks. Worry about panic attacks, and the effort spent trying to avoid attacks, cause significant problems in various areas of the person’s life, including the development of agoraphobia (see below).