Circadian Rhythms and Sleep in Familial DSPS and ASPS

BACKGROUND:

Tremendous progress in the past few years has led to the identification of several circadian clock genes. This now makes it possible to determine how alterations of human circadian clock genes and their expression could lead to differences in circadian and sleep/wake cycle phenotypes. Of particular interest for understanding genetics of the human circadian system are individuals with sleep phase disorders, such as DSPS and advanced sleep phase syndrome (ASPS), because recent studies indicate a genetic basis for these disorders. While it is assumed that both ASPS and DSPS are disorders of circadian timing, little is known about how the circadian clock system, or its interaction with sleep processes, are affected in these individuals.

DESIGN NARRATIVE:

Participants will complete questionnaires and actigraphy to determine sleep patterns and quality.

Inclusion criteria

for ASPS Participants:

• Morning type score on the Horne-Ostberg questionnaire
• Advanced melatonin onset

Inclusion criteria

for DSPS Participants:

• Evening type score on the Horne-Ostberg questionnaire
• Delayed melatonin onset

Inclusion criteria

for Controls:

• A stable sleep/wake pattern with a normal phase relationship to the environment and no history of sleep disorders

Exclusion criteria

for all subjects:

• Sleep disorder, other than DSPS or ASPS, as assessed by the Pittsburgh Sleep Quality Index and/or by polysomnogram
• History of cognitive or other neurological disorders
• History of Diagnostic and Statistical Manual-IV criteria for any major psychiatric disorder, alcohol or substance abuse
• Abnormal mood as assessed by the Hamilton Depression Scale
• History of, or concurrent, unstable or serious medical illness
• Current use of psychoactive medications, including antidepressants, anxiolytics, neuroleptics, anticonvulsants, hypnotics, and stimulant medications
• Shift work
• Having a daily caffeine intake greater than 4 cups per day
• Smoking
• Travel across more than 2 time zones within 90 days of the study
• Pregnancy or the desire to become pregnant during the study period