Interactions between evening and nocturnal cortisol secretion and sleep parameters in patients with severe chronic primary insomnia.
Level 4 - case-series / case-control
Case-control comparative study
PubMed 11988351 · doi:10.1016/s0304-3940(02)00192-1
What was done
Hourly evening and nocturnal plasma cortisol levels and sleep parameters were measured and compared between seven male patients with severe chronic primary insomnia and age- and gender-matched healthy controls.
What was found
No exact numerical values, effect sizes, or p-values are reported in the abstract. Evening and nocturnal cortisol secretion levels were significantly increased in patients compared to controls. Evening cortisol levels correlated significantly with the number of nocturnal awakenings in both patients and controls. Additionally, patients exhibited significant correlations between sleep parameters and cortisol secretion during the first 4 hours of the night.
Why it matters
This study provides physiological support for the hyperarousal hypothesis in chronic primary insomnia, suggesting a potential reciprocal relationship between HPA-axis hyperactivity and nocturnal awakenings.
Limits
The sample size is extremely small (7 patients and matched controls) and restricted solely to males. The abstract lacks quantitative data and statistical metrics. As an observational case-control design, it cannot establish whether HPA-axis activation causes insomnia or is a secondary consequence of chronic sleep disturbance.
Cited by
- partial Patients with sleep maintenance insomnia exhibit an abnormal spike in cortisol in the middle of the night that predicts awakenings.