Johnson, S.K., DeLuca, J. and Natelson, B. (1996) Per-sonality dimensions in the chronic fatigue syndrome: A comparison with multiple sclerosis and depression. Journal of Psychosomatic Research, 30, 9-0.
 Wessely, S., Chalder, T., Hirsch, S., Wallace, P. and Wright, D. (1996) Psychological symptoms, somatic symptoms, and psychiatric disorder in chronic fatigue and chronic fatigue syndrome: A prospective study in the primary care setting. American Journal of Psychiatry, 153, 1050-1059
 Buchwald, D., Pearlman, T., Kith, P., Katon, W. and Schmaling, K. (1997) Screening for psychiatric disorders in chronic fatigue and chronic fatigue syndrome. Journal of Psychosomatic Research, 42, 87-94.
 Jason, L.A., Taylor, R.R., Kennedy, C.L., Song, S., John-son, D. and Torres, S. (2001) Chronic fatigue syndrome: Comorbidity with fibromyalgia and psychiatric illness. Medicine and Psychiatry, 4, 29-34.
 Morriss, R. K., Wearden, A. J. and Battersby, L. (1997). The relation of sleep difficulties to fatigue, mood and disability in chronic fatigue syndrome. Journal of Psy-chosomatic Research, 42, 597-605.
 Claypoole, K.H., Noonan, C., Mahurin, R.K., Goldberg, J., Erickson, T. and Buchwald, D. (2007) A twin study of cognitive function in chronic fatigue syndrome: The ef-fects of sudden illness onset. Neuropsychology, 21, 507-513.
 Grafman, J., Schwartz, V., Dale, J.K., Scheffers, M., Houser, C. and Straus, S.E. (1993). Analysis of neuro-psychological functioning in patients with chronic fa-tigue syndrome. Journal of Neurology, Neurosurgery, and Psychiatry, 56, 684-689.
 Ciccone, D.S., Busichio, K., Vickroy, M. and Natelson, B.H. (2003) Psychiatric morbidity in the chronic fatigue syndrome: Are patients with personality disorder more physically impaired? Journal of Psychosomatic Research, 54, 445-452
 Komaroff, A.L., Fagioli, L.R., Doolittle, T.H., Gandek, B., Gleit, M.A., Guerriero, R.T., et al. (1996) Health status in patients with chronic fatigue syndrome and in general population and disease comparison groups. The American Journal of Medicine, 101, 281-290.
 Morriss, R.K., Ahmed, M., Wearden, A.J., Mullis, R., Strickland, P., Appleby, L., et al. (1999) The role of de-pression in pain, psychological syndromes and medically unexplained symptoms associated with chronic fatigue syndrome. Journal of Affective Disorders, 55, 143-148.
 Harvey, S.B., Wadsworth, M., Wessely, S. and Hotopf, M. (2007) The relationship between prior psychiatric disor-der and chronic fatigue: Evidence from a national birth cohort study. Psychological Medicine, doi: 10.1017/ S0033291707001900.
 Tiersky, L.A., Matheis, R.J., DeLuca, J., Lange, G. and Natelson, B.H. (2003) Functional status, neuropsy-chological functioning, and mood in chronic fatigue syn-drome (CFS). Journal of Nervous and Mental Disease, 191, 324-331.
 Jason, L.A., Torres-Harding, S., Friedberg, F., Corradi, K., Njoku, M.G., Donalek, J., et al. (2007). Non-phar-macologic interventions for CFS: A randomized trial. Journal of Clinical Psychology in Medical Settings, 14, 275-296.
 Fukuda, K., Straus, S.E., Hickie, I., Sharpe, M.C., Dob-bins, J.G. and Komaroff, A. (1994) The Chronic Fatigue Syndrome: A comprehensive approach to its definition and study. Annals of Internal Medicine, 121, 953-959.
 Jason, L.A., Ropacki, J.A., Santoro, N.B., Richman, J.A., Heatherly, W., Taylor, R., et al. (1997). A screening scale for chronic fatigue syndrome: Reliability and validity. Journal of Chronic Fatigue Syndrome, 3, 39-59.
 Spitzer, R.L., Williams, J.B.W., Gibbon, M. and First, M.B. (1995) Structured Clinical Interview for the DSM-IV—Non-Patient Edition (SCID—NP, Version 2.0). Washington, DC: American Psychiatric Press.
 McHorney, C.A., Ware, J.E. and Raczek, A.E. (1993). The MOS 36-Item Short-Form Health Survey (SF-36): II. Psychometric and clinical tests of validity in measuring physical and mental health constructs. Medical Care, 31, 247-263.
 McHorney, C.A., Ware, J.E., Lu, A.W. and Sherbourne, C.D. (1994) The MOS 36-item Short-Form Health Sur-vey (SF-36): III. Tests of data quality, scaling assump-tions, and reliability across diverse patient groups. Medical Care, 32, 40-66.
 Krupp, L.B., LaRocca, N.G., Muir-Nash, J. and Steinberg, A.D. (1989) The Fatigue Severity Scale: Application to patients with multiple sclerosis and systemic Lupus ery-thematosus. Archives of Neurology, 46, 1121-1123.
 Pepper, C.M., Krupp, L.B., Friedberg, F., Doscher, C. and Coyle, P.K. (1993) A comparison of neuropsychiatric characteristics in chronic fatigue syndrome, multiple sclerosis and major depression. The Journal of Neuro-psychiatry and Clinical Neurosciences, 5, 200-205.
 Keller, S., Bann, C.M., Dodd, S.L., Schein, J., Mendoza, T.R. and Cleeland, C.S. (2004) Validity of the Brief Pain Inventory for use in documenting the outcomes of pa-tients with noncancer pain. The Clinical Journal of Pain, 20, 309-18.
 Natelson, B.H., Johnson, S.K., DeLuca, J., Sisto, S., Ellis, S.P., Hill, N., et al. (1995). Reducing heterogeneity in chronic fatigue syndrome: A comparison with depression and multiple sclerosis. Clinical Infectious Diseases, 21, 1204-1210.
 Kessler, R.C., Berglund, P., Demler, O., Jin, R. and Wal-ters, E.E. (2005) Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Co-morbidity Survey Replication. Archives of General Psy-chiatry, 62, 593-602.