The differential diagnosis of fatigue and executive dysfunction in primary care.

The diagnosis of the patient reporting fatigue or the signs of executive dysfunction can be perplexing for the primary care physician. Both symptoms are associated with a wide range of both somatic and psychiatric symptoms and often occur together, although they can exist independently. Using some simple diagnostic and mnemonic tools, such as BATHE, SIG E CAPS, and SWIKIR, may aid the clinician in differentiating possible causes of fatigue and executive dysfunction and determining whether they are signs of physical or mental disease.