Medical scientists have yet to find clear and consistent causes of generalized anxiety disorder (GAD). There are several prevailing theories on what may contribute to this illness. Factors associated with an increased incidence of GAD include family history, episodes of high stress, and reduced activity of some of the brain’s neurotransmitters. Other psychological disorders may also be connected with the presence of GAD, and they might also create a higher risk for the illness.
Family history is often thought of as one of the potential causes of generalized anxiety disorder, though it is usually not isolated from other causal factors. Many of the anxiety disorders occur with greater prevalence in those who have relatives with the same or similar conditions. Therefore, people with close family members with any of the anxiety disorders may be at increased risk for GAD.
A somewhat expected pattern in GAD is that people will report an incident that caused distress or worry before the condition manifested. Possibly the worry, shock, and difficulty associated with that incident is expressed by increased anxiety about many areas of life. From a psychological perspective, this strategy could make sense because it takes the focus off the initial incident that caused alarm. Alternately, relocating anxiety onto present events may be the person’s way of "justifying" the continued presence of extreme anxiety.
On the other hand, people with GAD don’t always report a concerning incident or experience. Also, there are lots of people who face anxiety-producing experiences and don’t develop GAD. Still, an episode of high stress might be one of the partial causes of generalized anxiety disorder.
Decreased levels of certain neurotransmitters, especially serotonin, norepinephrine and dopamine, have been associated with GAD. It’s hard to say if these decreases are causes or symptoms of the illness. Nevertheless, it is useful to understand the presence of a relationship between GAD and lower neurotransmitter levels. The involvement of these specific brain neurotransmitters suggests close ties between GAD and depressive illnesses. It also points the way toward treating both conditions with many of the same medications.
Generalized anxiety disorder has a high rate of co-occurrence with several other mental illnesses. It’s not known if other psychological conditions are clear causes of generalized anxiety disorder. Some illnesses most associated with GAD include mood disorders like depression or bipolar disorder. People with other anxiety disorders may have GAD, too. The condition is also frequently diagnosed in those who suffer from substance abuse or dependence.
