Hyper-Arousal in Chronic Primary Insomnia

Inclusion Criteria for Insomniacs:

• Men and women with primary insomnia of at least 3 months in duration
• ages 21-65 years old
• BMI <35 kg/m2 to enable microneurography
• Moderate to severe insomnia based on the Insomnia Severity Index (ISI) questionnaire
• Pittsburgh Sleep Quality Index (PSQI) > 5
• Self-reported habitual sleep duration < 6.5 hours

Inclusion criteria for good sleepers:

• 21-65 years old men and women with BMI <35 kg/m2
• No insomnia based on ISI questionnaire
• Self-reported habitual sleep duration ≥ 6.5 hours but < 9 hours
• PSQI<5
• Sleep efficiency on PSG with TRT of 8 hours > 85%
• No history of mental illness, shift work, circadian rhythm disorders

Exclusion criteria for both insomniacs and good sleepers:

• Sleep disorders other than insomnia as assessed by screening PSG (apnea-hypopnea index or AHI ≥ 10, PLM arousal index ≥ 5)
• Circadian rhythm sleep disorders
• Diabetic based on HbA1c ≥ 6.5 %. For those with HbA1c ≥ 6.0 but <6.5%, the non-diabetic condition will be confirmed by 2-h oral glucose tolerance test
• History of meeting DSM-IVR criteria based on the Mini International Neuropsychiatric Interview version 6.0 for any major psychiatric disorder
• Unstable or serious medical conditions
• Current, or use within the past month, of psychoactive (other than stable treatment with antidepressants), hypnotic, stimulant or analgesic medications (except occasional non-narcotic analgesics), beta blockers or alpha blockers
• Shift work or other types of self imposed irregular sleep schedules
• Habitual smoking
• Habitual alcohol consumption
• Pregnancy