This disorder basically develops as a result of matters concerning separation from one's home, belongings or separation from the people to whom an individual is attached. Usually occurring in children or adolescents, that is, before or at the age of 18, lasting a month or so, this disorder is responsible for causing substantial distress leading to social, academic or occupational impairment. It is basically marked by excessive brooding, persistent worry about losing or constantly fear of harm befalling a loved one, and a continuous fear or reluctance to be alone. Occurrence of nightmares showing separation from loved ones or family, along with repeated complaints of physical disorders such as headache, stomachache, nausea or vomiting are all symptoms of Separation Anxiety Disorder.
Separation Anxiety Disorder can also continue in adulthood. The only change in the adult version is that, during the later stages, it may culminate into a Panic disorder or Agoraphobia or both. These disorders are caused due to many factors such as an abnormality in the part of the brain which helps it recognize the amount of carbon dioxide in the blood, fooling it to believe that the amount of oxygen that the brain is getting isn't enough. This leads to an adrenaline rush, which thereby leads to all these symptoms. These disorders can also be inherited, which means some people have them in their genes. Parents with alcohol related problems can also make the child more vulnerable to this disorder.