The specific causes of anxiety disorders are unknown, in spite of one-in-eight Americans being affected by them. As with most mental illnesses, anxiety disorders are thought to be caused by a combination of factors. It's likely genetic, psychological and environmental factors come together to cause anxiety disorders. Medical conditions are also known to cause an anxiety disorder.
Medical Causes of an Anxiety Disorder
While anxiety can be experienced by anyone, for many people an anxiety disorder is linked to an underlying medical issue. In some cases, a medical issue may cause an anxiety disorder. In other cases, anxiety and the medical condition may be related, but the medical condition may not have caused the anxiety disorder.
Possible medical causes include:1
- Heart disease
- Thyroid problems (such as hypothyroidism or hyperthyroidism)
- Drug abuse and withdrawal (alcohol and benzodiazepines may particularly cause anxiety)
- Rare tumors that produce certain "fight-or-flight" hormones
- Muscle cramps or spasms
- And many others
While most anxiety disorders develop in childhood and young adulthood, a medical cause is more likely if the anxiety disorder develops later in life. While common, anxiety disorders related to substance abuse or withdrawal are often undiagnosed. Various medications may also cause anxiety disorder symptoms.
Genetic Causes of Anxiety Disorders
While an exact gene hasn't been pinpointed, it's thought that genetics play a role in causing anxiety disorders, or at least for increasing the risk of getting an anxiety disorder. Anxiety disorders and genetics have been shown to be linked through chromosomal irregularities, among other things. These findings are confirmed by studies using twins.
The link between anxiety disorders and genetics is better understood for specific disorders. For example, in panic disorder, a gene mutation that leads to dysfunction in the chemical systems of the brain has been identified. Additional likely genetic links include:
- An abnormal increased function in some brain receptors; an abnormal decreased function in others
- An imbalance of chemicals, like cortisol, linked to feelings of stress
- Impaired carbon dioxide receptors, leading to a state of chronic hyperventilation
Obsessive-compulsive disorder has shown a strong genetic link with a genetic influence of 45% - 65% in children and 27% - 47% in adults.
Psychological Causes of Anxiety Disorders
Anxiety disorders are also commonly associated with other psychiatric disorders like depression, as well as the medication used to treat some mental health conditions.
There are several psychological theories on the causes of anxiety disorders; however, each theory tends to only explain a portion of the symptoms of an anxiety disorder. Likely, some people are more susceptible to these psychological anxiety disorder causes due to genetics. Psychological theories about the cause of anxiety disorders include:
- Anxiety disorders as a manifestation of interpersonal conflict
- Anxiety disorders as a conditioned response learned over time
- Existence of dysfunctional thought patterns; for example, the overestimation of the amount of danger in a given situation