Exact causes of anxiety aren’t fully understood, but like with all illnesses and conditions, there are common denominators. Life experiences, such as traumatic events, can trigger anxiety disorders, especially if they are already prone to the condition. Inherited traits are another commonly noted factor.
Underlying health issues can bring on varying levels of anxiety. Sometimes signs and symptoms of an illness can be the driving force that indicates a physical problem and prompts a check-up that results in a diagnosis.
Medical problems commonly linked to anxiety include:
- Cardiovascular disease (heart disease)
- Hyperthyroidism and other thyroid problems
- Respiratory disorders, such as chronic obstructive pulmonary disease (COPD) and asthma
- Chronic pain
- Irritable bowel syndrome
- Rare tumours (particularly those that produce 'fight or flight' hormones)
As with any other brain-related illness, anxiety disorders are triggered by problems in the functioning of the brain circuits which regulate emotions such as fear. Severe or long-lasting stress changes the way nerve cells within these circuits transmit information within the brain (from one region to another).
Changes in certain brain structures which control memories, especially when linked with strong emotions, can also trigger anxiety disorders. Anxiety disorders can run in families, and it’s commonly noted that these can be inherited from one or both parents, in a similar way to any other genetic condition (for instance a genetic risk for heart disease or cancer).
Particularly those with an inherited susceptibility to an anxiety disorder, environmental factors (a trauma or significant event) can trigger the illness.