Also found in: Dictionary, Thesaurus, Medical, Legal.
A group of distinct psychiatric disorders characterized by marked emotional distress and social impairment, including generalized anxiety disorder, panic disorder, obsessive-compulsive disorder, and posttraumatic stress disorder.
Generalized anxiety disorder (GAD) is characterized by excessive worry, tension, and anxiety. Accompanying physical symptoms include muscle tension, restlessness, fatigability, and sleep disturbances. GAD occurs in around 4–6% of the population and is the most frequently encountered anxiety disorder in primary care, where sufferers may seek help for the physical symptoms of the disorder. Studies of fear in animals and clinical studies of people with GAD suggest that similar brain circuits are involved in both cases. For example, numerous complex connections to other brain areas allows the amygdala to coordinate cognitive, emotional, and physiological responses to fear and anxiety. Thus in the “fight or flight” response, the organism makes cognitive-affective decisions about how to respond to the perceived danger and has a range of somatic (increased heart and respiration rate) and endocrine (release of stress hormones) responses that act together to increase the likelihood of avoiding the danger. Various neurotransmitter systems are responsible for mediating the communication between the functionally connected regions. Medications acting on these systems are thus effective in treating GAD. Although benzodiazepines have often been used, selective serotonin reuptake inhibitors (SSRIs) and noradrenergic/serotonergic reuptake inhibitors (NSRIs) are currently viewed as first-line options because of their favorable safety profile. Psychotherapy has also proven effective in the treatment of GAD. Cognitive-behavioral psychotherapy focuses on using behavioral techniques and changing underlying thought patterns.
Panic disorder (PD) is characterized by repeated, sudden, and unexpected panic attacks. Panic attacks are accompanied by a range of physical symptoms, including respiratory (shortness of breath), cardiovascular (fast heart rate), gastrointestinal (nausea), and occulovestibular (dizziness) symptoms. The prevalence of PD is approximately 2% in the general population, is more common in women, and is often complicated by depression. The same brain circuits and neurotransmitters implicated in fear and GAD are also likely to play a role in PD. For treatment the first-line choice of medication should be an SSRI or NSRI. Benzodiazepines are effective alone or in combination with SSRIs, but their use as the only medication is generally avoided due to the potential for dependence and withdrawal. Cognitive-behavioral principles that address avoidance behavior and irrational dysfunctional beliefs are also effective.
Obsessive-compulsive disorder (OCD) is characterized by obsessions (unwanted, persistent, distressing thoughts) and compulsions (repetitive acts to relieve anxiety caused by obsessions). The disorder occurs in 2–3% of the population and often begins in childhood or adolescence. OCD is also seen in the context of certain infections, brain injury, and pregnancy. A range of evidence now implicates a brain circuit between the frontal cortex, basal ganglia, and thalamus in mediating OCD. Key neurotransmitters in this circuit include the dopamine and serotonin neurotransmitter system. SSRIs are current first-line treatments for OCD, with dopamine blockers added in those who do not respond to these agents. Behavioral therapy focuses on exposure and response prevention, while cognitive strategies address the distortions in beliefs that underlie the perpetuation of symptoms.
Social anxiety disorder (SAD) is characterized by persistent fears of embarrassment, scrutiny, or humiliation. People with SAD may avoid social situations and performance situations, resulting in marked disability. For some, symptoms are confined to one or more performance situations, while others may be generalized to include most social and performance situations. Generalized SAD is usually more severe and sufferers are more likely to have a family history of SAD. SAD is particularly common, with prevalence figures in some studies upwards of 10%. SAD is often complicated by depression, and people with SAD may self-medicate their symptoms with alcohol, leading to alcohol dependence. Brain-imaging studies have found that effective treatment with medication and psychotherapy normalizes activity in the amygdala and the closely related hippocampal region in SAD. SSRIs, NSRIs, and cognitive-behavioral therapy are all effective in the treatment of SAD. Monoamine oxidase inhibitors (MAOIs) and benzodiazepines are also known to be effective treatments, but have a number of disadvantages.
Posttraumatic stress disorder (PTSD) is an abnormal response to severe trauma. PTSD is characterized by distinct clusters of symptoms: reexperiencing of the event (for example, in flashbacks or dreams), avoidance (of reminders of the trauma), numbing of responsiveness to the environment, and increased arousal (for example, insomnia, irritability, and being easily startled). Although exposure to severe trauma occurs in more than 70% of the population, PTSD has a lifetime prevalence of 7–9% in the general population. Risk factors for developing PTSD following exposure to severe trauma include female gender, previous psychiatric history, trauma severity, and absence of social support after the trauma. Brain-imaging studies have suggested that in PTSD frontal areas of the brain may fail to effectively dampen the “danger alarm” of the amygdala. Whereas stress responses ordinarily recover after exposure to trauma, in PTSD they persist. There is growing evidence that functioning of the hypothalamic-pituitary-adrenal hormonal axis is disrupted in PTSD. However, other systems, such as serotonin and noradrenaline, may also be involved. Both SSRIs and cognitive-behavioral therapy are effective in decreasing PTSD symptoms. Behavioral techniques (using different forms of exposure in the safety of the consultation room) or cognitive retraining (addressing irrational thoughts on the trauma and its consequences) can both be helpful.