The effect of Primary circadian sleep disorders changes on sleep produces varied symptoms, which are discussed below

a. Delayed Circadian Rhythm Disorder (DCR) symptoms

Commonly referred to as the “Night Owls” they may experience one or more of the following symptoms:

c. Bimodal Circadian Rhythm Disorder (BCR) or Irregular Sleep/Wake Cycle symptoms

The person may experience one or more of the following symptoms:

Early morning Insomnia, lack of energy during the day, feeling tired in the mid day, early afternoon and/or evening.

An irregular sleep-wake schedule features multiple sleep episodes without evidence of recognizable circadian features of sleep and wakefulness.

Daily sleep logs demonstrate irregularity not only of sleep but also of daytime activities, including eating.

Difficulty falling asleep, an inability of staying asleep, and awaken one or more times during the night.

Alertness and ability to function may also be diminished

d. Non 24-hour Sleep/Wake Cycle symptoms

Most commonly found in blind people who may experience some of the following symptoms:

Cycling or inconsistent Insomnia that occurs at different times each night

Periodic episodes every few weeks or during the month where sleep/wake pattern is in sync with 24-hour day.

Lack of energy during the day, feeling tired in the mid day, early afternoon and/or evening

Alertness and ability to function may also be diminished.