1. By RAJA SITI MARDHIAH RAJA AZMI & AFIF NUHAA JUWAHIR

2. DEFINITION  People with circadian rhythm sleep disorders are unable to sleep and wake at the times required for normal work, school, and social needs. They are generally able to get enough sleep if allowed to sleep and wake at the times dictated by their body clocks.

3.  CIRCADIAN rhythm disorders driven by changes in the sleep-wake cycle has been identified as one of the major causes of depression, the fourth most disabling disease in Malaysia, affecting up to 10% of the population.

4.  “Up to 82% of depressed patients remain untreated due to social stigma, misdiagnosis, and under-treatment. More depressed patients are seen by primary care doctors than by actual psychiatrists, and a majority of them are not diagnosed. The remaining 18% receive antidepressant medications, but only 10% are adequately treated,” noted Prof Dr Mohamad Hussain Habil, past president of the Asean Federation for Psychiatry and Mental Health (AFPMH) at a media workshop organised by Servier Malaysia on “Circadian Rhythms and Depression” in conjunction with Mental Health Month.  http://thestar.com.my

5. Normal circadian rhythms  "morning people", who prefer to sleep and wake early, to "owls", "evening people" or "night people", who prefer to sleep and wake at late times. Whether they are larks or owls, people with normal circadian systems:owls  can wake in time for what they need to do in the morning, and fall asleep at night in time to get enough sleep before having to get up.  can sleep and wake up at the same time every day, if they want to.  will, after starting a new routine that requires their getting up earlier than usual, start to fall asleep at night earlier within a few days.

6. Circadian rhythm disorders  disruptions in a person’s “internal body clock” that regulates biological processes such as brain wave activity, hormone production, cell regeneration and other biological activities linked to this cycle.  change sleep-wake cycles, hormone release, body temperature and other important bodily functions.

7. Why Circadian rhythms are important in determining human sleep patterns??  The body’s “internal clock” controls the production of melatonin, a hormone that makes you sleepy.  Since this trigger is located just above our optic nerves, which relay information from the eyes to the brain, it receives information about incoming light.  So, generally, when there is less light, our body’s melatonin levels increase and we feel sleepy.

8. Human biological clock

9. Type of circadian rhythm sleep disorders  Extrinsic type  Two of these disorders are extrinsic (from Latin extrinsecus, from without, on the outside) or circumstantial:extrinsic  Jet lag, which affects people who travel across several time zones. Jet lag  Shift work sleep disorder, which affects people who work nights or rotating shifts Shift work sleep disorder

10. Intrinsic type  Delayed sleep phase syndrome (DSPS), characterized by a much later than normal timing of sleep onset and offset and a period of peak alertness in the middle of the night. Delayed sleep phase syndrome  Advanced sleep phase syndrome (ASPS), characterized by difficulty staying awake in the evening and difficulty staying asleep in the morning. Advanced sleep phase syndrome  Non-24-hour sleep-wake syndrome (Non-24), in which the affected individual's sleep occurs later and later each day, with the period of peak alertness also continuously moving around the clock from day to day. Non-24-hour sleep-wake syndrome  Irregular sleep-wake rhythm, which presents as sleeping at very irregular times, and usually more than twice per day (waking frequently during the night and taking naps during the day) but with total time asleep typical for the person's age. Irregular sleep-wake rhythm

11. Treatment for circadian rhythm sleep disorders  Possible treatments for circadian rhythm sleep disorders include:  Bright light therapy is used to advance or delay sleep, depending on how the circadian rhythm is shifted. Patients are exposed to high-intensity light (up to 10,000 lux) for a duration of 30–60 minutes at a time, the time of day depending on whether an advance or a delay is required.light therapy

12.  Behavior therapy where the patient is told to avoid naps, caffeine, and other stimulants. They are also told to not be in bed for anything besides sleep and sex. Behavior therapy  Medications such as melatonin, a naturally occurring sleep aid, or other short term sleep aids or wake-promoting agents can be beneficial. melatonin  Sleep phase chronotherapy progressively advances or delays the sleep time by 1–2 hours per day. [5] Sleep phase chronotherapy [5]

13. references  http://thestar.com.my/health/story.asp?file=/ 2011/10/23/health/9742748&sec=health http://thestar.com.my/health/story.asp?file=/ 2011/10/23/health/9742748&sec=health  http://en.wikipedia.org/wiki/Circadian_rhyth m_sleep_disorder http://en.wikipedia.org/wiki/Circadian_rhyth m_sleep_disorder