Shorter E: From Paralysis to Fatigue: A History of Psychosomatic Illness in the Modern Era. New York, Free Press, 1992.
Snaith RP, Taylor CM: Irritability: Definition, assessment, and associated factors. Br J Psychiatry 147:127, 1985.
Southwick SM, Krystal JH, Morgan CA, et al: Abnormal noradrenergic function in post traumatic stress disorder. Arch Gen Psychiatry 50:266, 1993.
Stein MB, Sareen J: Generalized anxiety disorder. New Engl J Med 373:2059, 2015.
Straus SE: The chronic mononucleosis syndrome. J Infect Dis 157:405, 1988.
Straus SE, Dale JK, Tobi M, et al: Acyclovir treatment of the chronic fatigue syndrome. N Engl J Med 319:1692, 1988.
Swartz MN: The chronic fatigue syndrome—one entity or many? N Engl J Med 319:1726, 1988.
Wessely S, Chalder T, Hirsch S, et al: Postinfectious fatigue: Prospective cohort study in primary care. Lancet 345:1333, 1995.
Wessely S, Powell R: Fatigue syndromes: a comparison of chronic “postviral” fatigue with neuromuscular and affective disorders. J Neurol Neurosurg Psychiatry 52:940, 1989.
Yehuda R: Post-traumatic stress disorder. N Engl J Med 346:108, 2002.
Chapter  23    Fatigue, Asthenia, Anxiety, and Depression
The Limbic Lobes and the Neurology of Emotion
Emotion may be defined as any feeling state—for example, fear, anger, excitement, love, or hate—associated with certain autonomic, mainly visceral bodily changes. If the emotion is intense, there may ensue a disturbance of intellectual functions, that is, a disorganization of rational thought and a tendency toward a more automatic behavior of unmodulated, stereotyped character.
In its most easily recognized human form, emotion is initiated by a stimulus, real or imagined, the perception of which involves recognition, memory, and specific associations. The emotional state that is engendered is mirrored in a psychic experience, that is, a feeling, which is purely subjective and known to others only through the patient’s verbal expressions or by judging his behavioral reactions. This behavioral aspect, for which we use the term affect, is in part autonomous (hormonal–visceral) and in part somatic and shows itself in the patient’s facial expression, bodily attitude, vocalizations, or directed voluntary activity. In other words, the components of emotion appear to consist of (1) the perception of a stimulus, which may be internal (an idea) or external, (2) the feeling, (3) the autonomic–visceral changes, (4) the outward display (affect), and (5) the impulse to a certain type of activity. In many cases of neurologic disease, it is not possible to separate these components from one another.