Causes of Anxiety
Genetic and Biological Factors
Anxiety disorders have a strong hereditary component, with heritability estimates ranging from 30% to 50%, meaning that genetic predisposition accounts for approximately one-third to one-half of the risk for developing these conditions. 1
- Specific gene polymorphisms and familial abnormalities in neurological anatomy are linked to increased likelihood of anxiety disorder onset and contribute to symptom severity 2
- Dysfunction in brain circuits that respond to danger underlies the core pathophysiology of anxiety disorders 3
- Genetic factors interact with environmental influences through epigenetic mechanisms, meaning that environmental triggers can alter gene expression related to anxiety 3, 2
- A single traumatic event can lead to alterations in the function of specific genes related to anxiety disorders, demonstrating how environment modifies genetic expression 2
Developmental and Age-Related Factors
- The median age of onset for anxiety disorders is approximately 11 years, though specific disorders emerge during predictable developmental phases 1
- Separation anxiety typically onsets during preschool and early school-age years 1
- Specific phobias emerge during school-age years 1
- Social anxiety develops in later school-age and early adolescent years 1
- Generalized anxiety, panic disorder, and agoraphobia typically onset in later adolescence and young adulthood 1
- Anxiety disorders increase in both frequency and severity during pregnancy and the postpartum period, affecting not only the mother but also the infant and family 1
- Behavioral inhibition, autonomic hyperreactivity, or negative affectivity in childhood may foreshadow later anxiety disorder development 1
Environmental and Psychosocial Factors
- Stressful or traumatic exposures play important etiologic roles in anxiety disorder development 1
- Insecure attachment patterns contribute to anxiety disorder risk 1
- Parent and parenting factors influence the onset and development of anxiety disorders 1
- Environmental factors work in concert with genetic predispositions, with environmental triggers often influencing the phenotypic expression of anxiety disorders 2
Medical and Substance-Related Causes
Before diagnosing a primary anxiety disorder, clinicians must rule out alternative medical causes including thyroid disease, cardiac disorders, respiratory conditions, and drug-related effects. 1
- Hormone-secreting tumors can produce anxiety symptoms 1
- Certain medications, particularly bronchodilators, can induce anxiety 1
- Alcohol withdrawal causes anxiety symptoms 1
- Narcotic withdrawal produces anxiety 1
- Stimulant use (including caffeine and illicit substances) triggers anxiety 1
- Hyperthyroidism mimics anxiety disorder symptoms 1
- Unrelieved pain and other distressing physical symptoms can manifest as anxiety 1
Comorbidity as Both Cause and Consequence
- Anxiety disorders are highly comorbid with each other, demonstrating both homotypic continuity (one anxiety disorder predicting another anxiety disorder) and heterotypic continuity (anxiety predicting other psychiatric conditions) 1
- The estimated prevalence of anxiety disorders in patients with major depressive disorder is 56%, suggesting shared underlying vulnerability 1
- Anxiety disorders frequently co-occur with substance use disorders, posttraumatic stress disorder, bipolar disorder, ADHD, learning and language disorders, behavior disorders, obsessive-compulsive disorder, eating disorders, and personality disorders 1, 3
- The presence of an anxiety disorder is significantly associated with at least one suicide attempt in large-scale epidemiologic studies 1
Gender-Specific Risk Factors
- Anxiety disorders affect almost twice as many women as men across most anxiety disorder subtypes 4
- There is a slight gender imbalance with a slightly higher prevalence among women (odds ratio: 1.5–2.2) 1
- Anxiety disorders increase in frequency and severity during pregnancy and the postpartum period specifically in women 1