These disorders can be caused by lifestyle factors (like shift work or frequent travel across time zones), biological factors (like delayed body clock in teens), or underlying health conditions. They often result in sleep deprivation, fatigue, and reduced daytime function, despite spending adequate time in bed.

Symptoms:

• Inability to fall asleep at the desired time (e.g., staying awake past midnight regularly)

• Difficulty waking up in the morning, even after sufficient sleep

• Daytime sleepiness, fatigue, and poor concentration

• Insomnia symptoms, especially when trying to sleep on a conventional schedule

• Mood disturbances such as irritability, depression, or anxiety due to irregular sleep patterns