Generalised anxiety disorder
Definition
At least 6 months of excessive worry about everyday issues that is disproportionate to any inherent risk, causing distress, or impairment.
The worry is not confined to features of another mental disorder, or as a result of substance abuse or a general medical condition.
At least 3 of the following emotional, somatic, and cognitive symptoms are present most of the time:
restlessness or nervousness
being easily fatigued
poor concentration
irritability
muscle tension
sleep disturbance
Other common complaints are autonomic in nature, such as sweating, lightheadedness, palpitations, dizziness, and epigastric discomfort. [2]
Anxiety may be 'free-floating' (i.e., not restricted to, or even strongly predominating in, any particular environmental circumstances). [2]
Examples of worries include fears that the patient or a relative will shortly become ill or have an accident.
Risk Factors
FHx of anxiety
Physical or emotional stress
Hx of physical or emotional trauma
Depression
Other anxiety disorder
Female gender
Diabetes
Differential diagnosis
Characterised by recurrent episodes of sudden onset of anxiety
Strong autonomic and physical complaints without the predominant picture of worry. [1]
At least 4 symptoms including shortness of breath, palpitations, shakiness, nausea, hot or cold flushes, dizziness, and fear of dying.
Panic may exist along with GAD
Anxiety or persistent fear is limited to social situations and fear of social scrutiny or embarrassment. [1]
Anxiety is directly related to compulsions or obsessions.
Post-traumatic stress disorder
Anxiety is directly related to exposure to reminders of past trauma.
Anxiety is directly related to specific physical complaints.
Thorough medical evaluation shows no basis for physical complaints.
Substance- or drug-induced anxiety disorder
Anxiety is directly related to exposure to:
substance (e.g., caffeine, toxin, alcohol, illicit drug)
drug (e.g., salbutamol, theophylline, corticosteroid, antidepressant)
herbal medicine (e.g., ma huang, St. John's wort, ginseng, guarana, belladonna).
CNS-depressant withdrawal
Anxiety may occur during withdrawal of a substance (e.g., alcohol, opioids, sedative-hypnotics)
Characteristic symptoms such as shakiness (i.e., rapid heart rate, fluctuating blood pressure), and, if delirium is present, mental confusion.
Typical signs on are tachypnoea, tachycardia, and disorientation
Anxiety is directly related to a fear of gaining weight.
Body weight <85% of ideal.
Situational anxiety (non-pathological)
Anxiety can be avoided and is more controllable and less pervasive.
Situational worries are less likely to be accompanied by physical symptoms. [1]
Restlessness, fatigue, and other physical symptoms are rarely present.
Adjustment disorder
Anxiety occurs temporarily in response to a life stressor and does not persist for more than 6 months after the stressor ends.
Cardiac disease
Anxiety symptoms are predominantly cardiac in nature
Palpitations, sensation of rapid heartbeat or skipped heartbeat, dizziness, dyspnoea on exertion, chest pain, and numbness
Chest pain is typically exertional.
Pulmonary conditions
Weight loss, warm moist skin, heat intolerance, ophthalmopathy, or goitre.
TFTs (increased T4, decreased TSH) can identify primary hyperthyroidism or use of excessive thyroid hormone.
Infections
Anxiety limited to the time period of the infection.
Typically, burning epigastric pain which occurs hours after meals or with hunger, relieved by food or antacids.
Chronic diarrhoea, weight loss, and right lower quadrant abdominal pain mimicking acute appendicitis.
Perianal lesions including skin tags, fistulae, abscesses, scarring or sinuses.
Alteration of bowel habits associated with pain, and abdominal discomfort, bloating, or distention.
Epidemiology
Generalised anxiety disorder (GAD) usually occurs along with other mental disorders. [5] [6] [7]
One study in Europe showed that 76% of people who had more than 1 mental disorder for 12 months had GAD.
In the US, GAD has an estimated lifetime prevalence of 5% and a 12-month prevalence of 3%
About two thirds of patients diagnosed are female, and more women (55% to 60%) than men are diagnosed in clinical settings. [1]
Over half of the people seeking help have an onset in childhood or adolescence.
Diagnosis is less common in people over 65 years of age. [9] [10]
A large US epidemiological study found that almost half of people retained the diagnosis over 2 years after diagnosis. [5]
Aetiology
No single aetiology exists
An increase in minor life stressors, [13] [14] presence of physical or emotional trauma, [15] and genetic factors seem to contribute.
A systematic review found that bullying or peer victimisation among youths was associated with an increased incidence. [16]
A review of 35 twin and family studies found a significant association with other anxiety disorders and depression, suggesting a common underlying genetic factor. [18]
Abnormality of chromosome 15 has been associated with panic, agoraphobia, social phobia, and joint laxity in families, and with panic disorder in non-familial cases.
However, this data is preliminary only
Further investigations, including more sophisticated studies of genetic markers, are warranted to substantiate this and identify other genetic factors associated with anxiety disorders. [19]
Clinical features
Presence of risk factors
Excessive worry for at least 6 months
Anxiety not confined to another mental disorder
Anxiety not due to medication or substance
Muscle tension
Sleep disturbance
Fatigue
Restlessness
Irritability
Poor concentration
Headache
Sweating
Dizziness
GI symptoms
Muscle aches
Increased heart rate
Shortness of breath
Trembling
Exaggerated startle response
Chest pain
Pathophysiology
Not clearly understood
Studies have identified changes in cerebral blood flow in response to stress
Hypervigilance and increased metabolic activity suggest hyperactive brain circuitry. [20]
Multiple neurotransmitters involving wide areas of the brain have been implicated in anxiety and other disorders [21]
Including receptors for benzodiazepines, N-methyl-D-aspartate/glutamate, serotonin, and cholecystokinin.
Abnormalities in brain corticotrophin-releasing factor secretion in the hypothalamic-pituitary-adrenal axis appear to co-occur with anxiety episodes
May adversely affect neurotransmitters and arousal. [22]
The associated heightened vigilance and arousal are associated with insomnia and diurnal fatigue. [23]
Investigations
DSM-IV-TR criteria for GAD:
At least 6 months of excessive worry about everyday issues that is disproportionate to any inherent risk, causing distress, or impairment.
The worry is not confined to features of another mental disorder or as a result of substance abuse or a general medical condition.
At least 3 of the following symptoms are present most of the time:
restlessness or nervousness, being easily fatigued, poor concentration, irritability, muscle tension, or sleep disturbance. [1]
Tests to rule out other conditions:
TFTs
urine drug screen
24-hour urine for vanillylmandelic and metanephrines
end-stage metabolites of the catecholamines epinephrine and norepinephrine
pulmonary function tests
ECG
echocardiogram
EEG
Management
a) conservative
CBT
Psychotherapy
Applied relaxation
b) medical
Hydroxyzine
Benzodiazepines
Antidepressants if depression coexists
SSRIs, SNRIs, or buspirone are considered the drugs of choice
c) surgical
Prognosis
Pharmacotherapy should be given for at least 6 to 8 weeks to determine efficacy, and continued for up to 6 to 12 months if effective. [27]
The physician may attempt to taper the medication after this period, monitoring the patient for recurrence of symptoms.
With proper treatment, a decrease in symptoms, improved psychosocial functioning, and a reduction in over-utilisation of medical care can be achieved.
Generalised anxiety disorder may recur under physical or emotional stress.