Delayed Sleep Phase Disorder (DSPD) is a circadian rhythm sleep disorder where a person's sleep-wake cycle is significantly delayed. Individuals with DSPD typically find it difficult to fall asleep until late at night, often after midnight, and struggle to wake up in the morning. This misalignment can lead to insufficient sleep and daytime sleepiness. People with DSPD may experience challenges in daily life, such as difficulty attending work or school on time. The condition is often diagnosed in adolescents and young adults, but it can affect individuals of any age. Treatment options may include light therapy and behavioral interventions to help reset the sleep cycle.