Melatonin and psychobiological stress reactivity – does melatonin protect against stress?

Project leader: Petra Wirtz
Project duration: 2005 – 2008
Funding: Foundation for Research in Science and the Humanities at the University of Zurich (2004 to PW)

There are hints that the pineal hormone melatonin exhibits stress-protective properties. Animal trials have shown that dispensing melatonin can lead to reduced glucocorticoid release after stimulation. The stress-induced release of stress hormones, in turn, results in certain memory effects, such as improved memory consolidation during stressful situations and impaired retrieval of previously learned content.
The project examined the effect of 3 mg of melatonin on stress reactivity in humans as well as on stress-induced memory effects. In a double-blind setup, healthy men were given either melatonin or a placebo. Both groups then underwent a standardised psychosocial lab stress test (TSST). The stress reactivity of the hypothalamus-pituitary-adrenal axis (HPA) was recorded via oral cortisol, the reactivity of the sympathetic nervous system via the catecholamines adrenaline and norepinephrine as well as the continuous monitoring of heart rate and blood pressure. A series of psychometric variables as well as memory tests rounded out this study of aspects of stress reactivity.

Wirtz, P.H., Spillmann, M., Bärtschi, C., Ehlert, U. & Von Känel, R. (2008). Oral Melatonin Reduces Blood Coagulation Activity: a Placebo-Controlled Study in Healthy Young Men. J Pineal Res 44: 127-133. [Link]

Wirtz, P.H., Baertschi, C., Spillmann, M., Ehlert, U. & Von Känel, R. (2008). Effect of oral melatonin on the procoagulant response to acute psychosocial stress in healthy men: a randomized placebo-controlled study. J Pineal Res 44(4): 358-365. [Link]

Rimmele, U., Spillmann, M., Bärtschi, C., Wolf, O.T., Ehlert, U. & Wirtz, P.H. (2009). Melatonin improves memory acquisition under stress independent of stress hormone release. Psychopharmacology 202:663-6672. [Link]