Severe or Chronic Medical Conditions. Depression follows or is caused by many medications or serious medical problems. A number of studies have associated low cholesterol and high triglyceride levels with depression, although it is not clear whether these factors or accompanying health problems reduce spirits. Some experts believe that a syndrome of migraine headaches, anxiety, and depression, which occurs in some people, is caused by single genetic defect that regulates dopaminea chemical messenger in the brain. Emotional and Personality Disorders .
Chronic depression is a frequent companion to anxiety disorders.
Personality disorders, such as borderline and avoidant personalities, appear to strongly predispose people not only to a first episode of depression but to relapses. A person with a borderline personality disorder is one who acts impulsively and has a poor self-image and unstable relationships. Substance Abuse and Addictions . Internet addiction is a recent phenomenon that may a pose risk for depression. The more time spent on the web, the higher the depression scores.