Anxiety plays a part in many people's lives at various times. The anxiety subsides when people know the cause, which is often something upsetting for a certain period. Unexplained anxiety can cause continual conflict and disruption for people who do not understand why they have become so anxious. They can develop such problems as generalized anxiety disorder, panic disorder, phobias or obsessive-compulsive disorder. For many of them, certain causes may explain their anxiety.
Genetics
Some anxiety disorders appear to run in families, according to the University of Maryland Medical Center. Studies indicate that identical twins with an anxiety disorder are more likely to have a twin with an anxiety disorder than non-identical or fraternal twins, suggesting some people may be predisposed to anxiety. This differs from people with post-traumatic stress disorder, an anxiety disorder usually caused by exposure to a past trauma.
Brain Chemistry
Parts of the brain involved with fear and anxiety may play significant roles in anxiety disorders. The amygdala deep in the brain alerts the brain to potential threats for a response. Emotional memories stored in the amygdala may trigger fears associated with phobias, according to the National Institute of Mental Health. People with obsessive-compulsive disorder may have insufficient levels of serotonin, according to the Mayo Clinic. Brain-imaging research shows that these patients have different brain activity than people who do not have the anxiety disorder. Medication that enhances serotonin, a brain chemical that affects emotions, reduces obsessive-compulsive symptoms.
Environment
A childhood that includes abuse, violence or poverty can bring about unexplained anxiety throughout life. An abusive or traumatic background increases the risk of developing generalized anxiety disorder, the Mayo Clinic says. Behaviors learned in childhood may result in obsessive-compulsive disorder for some people. Experiences during upbringing can make some people vulnerable to other anxiety disorders.
Personality
Low self-esteem or lack of coping skills may make some people more prone to anxiety disorders, according to the National Institute of Mental Health. Anxiety that begins in childhood could also cause a lack of self-worth and personality problems. The association between low self-esteem and unexplained anxiety can lead to people having multiple disorders, such as depression, anxiety disorder and personality disorder.
Stress
Stress leads to anxiety, which can turn into chronic anxiety if the cause is not recognized. Some people may not connect stressful conditions with the anxiety they later experience. People with health conditions or serious illness may develop anxiety about their future. Even though their worries are understandable, their concerns can result in constant anxiety about other matters in their lives, which do not necessarily deserve such extreme anxiety.
