Researchers used standard sleep questionnaires to assess sleep problems and characteristics in ADHD (n = 122) and non-ADHD (n = 105) comparison youths. They concluded that ADHD may be one of the consequence of nightmares but is not an outcome of it.

This study is valuable to my study in that it teaches me to be skeptical regarding differentiating between outcome and cause.

4.

StRanjbaran, Z., Keefer, L., Farhadi, a., Stepanski, E., Sedghi, S. And Keshavarzian, a. (2007), Impact of sleep disturbances in inflammatory bowel disease. Journal of Gastroenterology and Hepatology, 22: 1748 -- 1753.

Study showed that inflammatory bowel disease (IBD) patients have significant sleep disturbance even when their disease is not active. This problem might affect quality of life, gastrointestinal symptoms and coping ability, and might potentially increase or decrease disease severity. A self-administered, mail-in questionnaire package was sent to 205 subjects using the Pittsburgh Sleep Quality Index...
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