I had problems with severe lack of sleep with my oldest (and resulting depression). (amotherinisrael.com)
However, the issue is not only about cases of severe lack of sleep, like surviving an entire week with only 4 - 5 hours of sleep per night. (fitnessandpower.com)
Sometimes, you or your partner may suffer from a severe lack of sleep even if your child is showing signs that co sleeping is improving his or her sleeping habits. (abckidsinc.com)