Anxiety disorders

Abstract

Anxiety disorders form the most common group of mental disorders and generally start before or in early adulthood. Core features include excessive fear and anxiety or avoidance of perceived threats that are persistent and impairing. Anxiety disorders involve dysfunction in brain circuits that respond to danger. Risk for anxiety disorders is influenced by genetic factors, environmental factors, and their epigenetic relations. Anxiety disorders are often comorbid with one another and with other mental disorders, especially depression, as well as with somatic disorders. Such comorbidity generally signifies more severe symptoms, greater clinical burden, and greater treatment difficulty. Reducing the large burden of disease from anxiety disorders in individuals and worldwide can be best achieved by timely, accurate disease detection and adequate treatment administration, scaling up of treatments when needed. Evidence-based psychotherapy (particularly cognitive behavioural therapy) and psychoactive medications (particularly serotonergic compounds) are both effective, facilitating patients' choices in therapeutic decisions. Although promising, no enduring preventive measures are available, and, along with frequent therapy resistance, clinical needs remain unaddressed. Ongoing research efforts tackle these problems, and future efforts should seek individualised, more effective approaches for treatment with precision medicine.

Figure 1:. Visual representation of components of the brain’s threat-responsive circuitry

Threats are classified on the basis of proximity, with the top of the figure showing a threat continuum, including distant predators, an approaching threatening person, or a direct encounter with painful stimuli. Components of the brain’s circuitry involved in threat responses appear in distinct colours, with the hippocampus in blue, stria terminalis and its bed nucleus in green, amygdala in red, and frontal regions, including the medial prefrontal cortex and insula, in purple. These circuitry components interact in unique ways depending on the nature of threats, thereby generating adaptive defensive responses shown at the bottom of the figure, including avoidance, freezing, fleeing, and fighting. BNST=bed nucleus of the stria terminalis.

Figure 2:. Effect sizes of different treatments in reducing anxiety symptoms based on meta-analytic evidence

CBT=cognitive behavioural therapy. GAD=generalised anxiety disorder. iCBT=therapist-assisted internet cognitive behavioural therapy. PD=panic disorder. SAD=social anxiety disorder. *Based on network meta-analysis; therefore, sample size reflects all studies included, not just for the specific contrast.