Basic medical training has paid little attention to sleep problems; according to Benca in her review "Diagnosis and Treatment of Chronic Insomnia" (2005), most doctors are "not well trained with respect to sleep and sleep disorders," and a survey in 1990–91 of 37 American medical schools showed that sleep and sleep disorders were "covered" in less than two (2) hours of total teaching time, on average. Benca's review cites a 2002 survey by Papp et al. of more than 500 primary care physicians who self-reported their knowledge of sleep disorders as follows: Excellent – 0%; Good – 10%, Fair – 60%; and Poor – 30%. The review of more than 50 studies indicates that both doctors and patients appear reluctant to discuss sleep complaints, in part because of perceptions that treatments for insomnia are ineffective or associated with risks, and: