Circadian Rhythm Sleep Disorders (CRSD) are a group of sleep disorders characterized by a de-synchronization between a person's biological clock and the environmental 24-hour schedule. There are four main types of CRSD, namely, Delayed Sleep Phase Syndrome (DSPS) (the most common), Advanced Sleep Phase Syndrome (ASWD), Non-24-hour Sleep-Wake Syndrome (Free-Running Pattern) and Irregular (or Disorganized) Sleep Wake Pattern. These disorders lead to harmful psychological and functional difficulties and certain personality disorders may also be related to them. It has been found that psychotropic drugs, SSRI and haloperidol can cause CRSD, and this is also true for some cases of minor head trauma. They are often misdiagnosed and incorrectly treated due to the fact that many doctors are unfamiliar with them. This review describes the disorders, their consequences and available treatment.