It is normal to feel anxiety. You might feel anxious about an upcoming exam, or starting a new job. However, anxiety disorders are more complex and can affect a person's daily activities. There are several types of anxiety disorders, from panic disorder to social anxiety disorder, and the effects of all can worsen over time.
However, researchers aren't completely sure what causes anxiety disorders. "The cause of generalized anxiety disorder is not known," according to the University of Michigan Health System's Department of Psychiatry. "Some studies show that it might be passed through the family (genetic)."
A recent study published in the journal Current Biology appears to corroborate the idea that anxiety could be encoded in your biology. "If you're anxious, you're hardly to blame," Damiaan Denys, a University of Amsterdam psychiatry researcher said, according to Reuters. "It is not a choice or a lack of willpower."
According to the National Institute of Mental Health, symptoms of anxiety disorders generally depends on the type, but general symptoms include: restlessness or feeling wound-up or on edge, being easily fatigued, difficulty concentrating or having their minds go blank, irritability, muscle tension, difficulty controlling the worry, sleep problems (difficulty falling or staying asleep or restless, unsatisfying sleep).
"The distinction between an anxiety disorder and just having normal anxiety is whether your emotions are causing a lot of suffering and dysfunction," Sally Winston, co-director of the Anxiety and Stress Disorder Institute of Maryland, told Health. Researchers are starting to find that anxiety disorders may be caused by a combination of risk factors, such as past stressful events, or environmental stressors.