As with most conditions which affect your mental health, the exact cause of generalised anxiety disorder (GAD) is not fully understood. Some people develop the condition for no apparent reason. Other people may develop GAD following a major stressful incident, or event.

Neurotransmitters

Some research has suggested that GAD may be caused by an imbalance of certain chemicals which occur naturally in your brain. These chemicals are known as neurotransmitters.

Two of the neurotransmitters that are thought to affect anxiety are serotonin and norepinephrine. If the level of these chemicals in your brain becomes unbalanced, it can significantly affect your mood, and increase the likelihood that you will develop anxiety-related conditions, such as GAD.

Combination of causes

GAD is most likely to have a complex combination of causes, and the condition is not just triggered by an imbalance of brain chemicals. Researchers believe that the condition is caused by a combination of factors including your:

• body's biological processes,
• genetics,
• environment, and
• life experience.