Does sleep deprivation decrease IQ?

Yes. I haven't seen that magazine, but it sounds like it is citing Stanley Coren's book Sleep Thieves. Coren is a neuropsychologist at the University of British Columbia. Coren says that sleep deprivation affects focus and short-term memory capabilities, which are directly related to IQ. read more

Sleep deprivation cannot decrease a person’s IQ permanently. The decrease in an IQ score would be due to temporary degradation of cognitive resources. read more

Not only does it affect intelligence, lack of sleep also reduces impulse control. Via NurtureShock: A different mechanism causes children to be inattentive in class. Sleep loss debilitates the body’s ability to extract glucose from the bloodstream. read more

Less sleep lowers IQ scores and grades According to Coren, scores on intelligence tests decline cumulatively on each successive day that you sleep less than you normally sleep. The daily decline is approximately one IQ point for the first hour of sleep loss, two for the next, and four for the next. read more