Table 1.

Inclusion and exclusion criteria

	Inclusion criteria	Exclusion criteria
Patients with chronic fatigue	Persisting or constantly relapsing fatigue lasting 3 months or more	Another current disease process or demanding life event that might explain the fatigue
	Functional disability resulting from fatigue that prevents normal school attendance	Another chronic disease
	Age ≥12 and <18 years	Permanent use of drugs (including hormones) possibly interfering with measurements Permanently bed-ridden Positive pregnancy test Pheocromocytoma Evidence of reduced cerebral and/or peripheral circulation due to vessel disease Polyneuropathy Renal insufficiency Known hypersensitivity towards clonidine or inert substances (lactose, sucrose) in capsula Abnormal ECG (apart from ectopic beats) Supine heart rate <50 bpm Supine systolic blood pressure <85 mm Hg Upright systolic blood pressure fall >30 mm Hg
Healthy control subjects	Age ≥12 and <18 years	Another chronic disease Permanent use of drugs (including hormones)