Circadian Disorder Due to a Drug or Substance: any number of changes in circadian cycles directly due to the use of over-the-counter, prescription, or recreational drugs. A person experiencing this condition would not have circadian problems if they did not take the drug(s) that aggravates their sleep. Sleep patterns may be advanced, delayed, irregular, or free-running (see entries below). Drugs likely to precipitate circadian changes include: alcohol, sleeping pills, muscle relaxants, pain medications, certain anti-depressants, seizure medications, Parkinson’s medications, antihistamines, allergy medications, cancer therapies, blood pressure and heart medications, and certain herbs, vitamins and minerals. The doctor prescribing the medication or a sleep specialist may be able to adjust the dosage, type of medication, or patient activities to alleviate sleep problems. (See also Drugs and Sleep.)

Circadian Disorder Due to a Medical Condition: changes in circadian rhythms directly due to a medical condition. If the medical condition did not exist, then the circadian disruption would not exist. Depending on the disease or condition, sleep patterns may be advanced, delayed, irregular, or free-running. Medical conditions likely to disrupt circadian rhythms include: dementia disorders, movement disorders such as Parkinson’s Disease, blindness, certain liver diseases, kidney disease, and brain injuries. The doctor treating the aggravating condition or a sleep specialist will treat sleep issues with respect to the patient’s health. Good sleep behaviors, bright light therapy, or changes in medication often help. (See also Physical Illness and Sleep.)

Free-Running (Non-entrained Type):
a circadian rhythm disorder characterized by sleep times that are out of alignment with “normal” sleep times. Sleep is delayed a bit more each night, making it seem like a Delayed Sleep Phase. Eventually, sleep is delayed until morning and then afternoon, making it seem like an Advanced Sleep Phase. Sleep times move in and out of alignment as the cycle repeats itself. Treatment under the care of a sleep specialist aims to stimulate wakefulness at appropriate times, so that the circadian clock resets itself. Wakefulness is stimulated using bright light therapy and scheduled activity.

Irregular Sleep-Wake Rhythm: sleep cycles that are broken into small pieces. People with this condition nap frequently but briefly over a 24 hour period. There is no clear pattern of sleep. At night, it feels like insomnia because of the frequent awakenings. During the day, it feels like a hypersomnia or too much sleep. Irregular sleep patterns are normal in early infancy. In adulthood, it is associated with brain damage, dementia, or mental retardation. Treatment involves stimulation such as light therapy and planned activity to promote wakefulness during the day and sleep at night.

Suggested Downlaods

Out of Sync
Additional Circadian Rhythm Disorders
Children and Sleep
Aging and Sleep
Physical Illness and Sleep
Drugs and Sleep