Goal: We propose to test whether giving the supplement coenzyme Q10 (Q10) improves symptoms and subjective health in Gulf War veterans (GWV) with chronic, multi-symptom health problems.

Rationale: Direct empirical evidence, in groups that are not GWV, has supported benefit of Q10 to many of the symptoms that GWV are at heightened risk of experiencing, such as fatigue, muscle pain, and cognition, which are syndrome-defining conditions. In addition, Q10 has also been reported to benefit other symptoms arising at increased rates in GWV, including headaches, sleep disturbances, and breathing problems. This provides a strong rationale for testing whether Q10 will have similar benefit to these symptoms in GWV.

Method: 32 GWV with chronic health problems will participate. Each will be "crossed over" between Q10 for 3.5 months and an identical placebo, receiving each agent twice, for 3.5-month periods. In one of the Q10 phases, a lower dose of Q10 will be used (100 mg three times a day), while in one a higher dose will be used (300 mg three times a day). Neither subjects nor investigators will know which substance each subject is receiving in which phase.

Assessments: Assessments will include subjective quality of life; symptoms that are "syndrome-defining" for Gulf War illness (like fatigue and muscle problems) and other symptoms and conditions reported to occur more commonly in GWV (like sleep problems). Analyses will show whether Q10 led to improvements when compared to placebo; whether higher Q10 doses improved outcomes more than lower doses; and whether people with certain symptoms or characteristics get more benefit than people with other symptoms or characteristics.