Investigations
1st investigations to order
clinical diagnosis
Test
A thorough history and examination should be performed. There are no tests to exclude GAD.
GAD is defined by the Diagnostic and Statistical Manual of mental disorders, fifth edition, text revision (DSM-5-TR) criteria as at least 6 months of excessive anxiety and worry about a number of events or activities, causing distress or impairment. The worry is not confined to features of another mental health disorder or a result of substance misuse or a general physical health condition. At least three of the following symptoms are present most of the time in adults: restlessness or nervousness, being easily fatigued, poor concentration, irritability, muscle tension, or sleep disturbance (only one item is required in children).[1]
Result
meets clinical criteria for GAD; physical health conditions, other mental disorders, and medications or substances should be ruled out as a primary cause
Investigations to consider
thyroid function tests
Test
Ordered for patients with anxiety plus symptoms suggestive of thyroid disease, such as unexplained weight loss, exophthalmos, goitre, or for a woman with anxiety and a family history of thyroid disease.
Increased thyroxine or decreased thyroid-stimulating hormone suggests overactive thyroid or excessive thyroid replacement.
Result
normal thyroid-stimulating hormone and thyroxine
urine drug screen
Test
Reserved for when there is a strong suspicion of substance misuse, such as a patient with a history of alcohol or other drug misuse.
May miss cocaine, which is rapidly metabolised and excreted.
Result
negative for stimulants
24-hour urine for catecholamines, metanephrines, normetanephrines, and creatinine
Test
If severe hypertension and/or tachycardia exists with anxiety, this test is recommended to rule out phaeochromocytoma. This is a rare clinical situation.
Increased level suggests increased catecholamines.
Result
normal
pulmonary function tests
Test
Can be ordered when pulmonary disease is suspected as a cause for shortness of breath, but is rarely used for patients with anxiety. Anxiety symptoms frequently co-occur in people with chronic respiratory disorder.
May show reactive airway disease or emphysema.
Result
normal FEV₁
ECG
Test
Ordered for patients with abnormal cardiac auscultation, symptoms or risk factors for cardiac disease, syncope, or a strong family history of cardiac disease.
Presence of arrhythmias, evidence of old or new ischaemic changes, or presence of conduction defects suggests underlying cardiac pathology.
Result
normal sinus rhythm
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