Exclusion Criteria n Past or current diagnosis of major depression with psychotic or melancholic features, bipolar disorder, schizophrenia, delusional disorders, dementia, bulimia nervosa, anorexia nervosa n Active medical conditions n Previously diagnosed conditions with unclear resolution (malignancies, hepatitis B or C) n Alcohol or substance abuse within 2 yrs of onset of fatigue n Severe obesity (BMI ³ 45)