The Pittsburgh sleep quality index basically discriminates between "good" and "poor" sleepers. Time-frame of such evaluation is in the month before the test. It consists of 18 questions grouped into seven component scores, each weighted on a 0 to 3 scale, for a total score of 21, with higher scores indicating poorer sleep quality. Components include assessment of sleep duration (total sleep time), sleep disturbances, sleep latency, day dysfunction due to sleepiness, sleep efficiency, overall sleep quality, and medications needed to sleep. Total sleep time will be categorized as follows: <6 hours, 6 to 7 hours, 7 to 8 hours (referent category), 8 to 9 hours, and >9 hours. The original instrument also includes five additional questions that should be directed to bedpartners or roommates. Such questions will not be used in the present survey as they are not included in the scoring and have not been validated in the Spanish language.