Lack of sleep is associated with increased risk of cardiovascular disease, depression, diabetes, hypertension and sexual dysfunction. A new study now shows that lack of sleep also affects social interactions, making people less willing to help others. MRI scans of sleep-deprived reveal less activation of empathy parts of brain. Assessments of sleep-deprived also show decreased desire to help others. Charitable giving even drops 10% after the beginning of Daylight Saving Time.