Linking light exposure and subsequent sleep: a field polysomnography study in humans

Marijke Gordijn is a co-author of a study featured at Sleep. Study objectives To determine the effect of light exposure on subsequent sleep characteristics under ambulatory field conditions. Methods Twenty healthy participants were fitted with ambulatory PSG and wrist-actigraphs to assess light exposure, rest-activity, sleep quality, timing and architecture. Laboratory salivary dim-light melatonin onset (DLMO)…

Is there a relationship between vegetarianism and Seasonal Affective Disorder? A pilot study.

Marijke Gordijn is co-author of a study investigating the relationship between vegetarianism and winter depression, together with researchers from Finland and the university medical center in Groningen. A Background and Aim: Seasonal patterns of food intake are found in healthy individuals and particularly in patients with seasonal affective disorder (SAD). One nutritional choice is a…

Premenstrual mood and empathy after a single light therapy session

To examine whether acute changes in cognitive empathy might mediate the impact of light therapy on mood, we assessed the effects of a single light-therapy session on mood and cognitive empathy in 48 premenstrual women, including 17 who met Premenstrual Symptoms Screening Tool criteria for moderate-to-severe premenstrual syndrome / premenstrual dysphoric disorder (PMS/PMDD). Using a…

Sleep disturbances in Phenylketonuria: an explorative study in men and mice.

Marijke Gordijn is coauthor of a study investigating sleep disturbances in PKU. Sleep problems have not been directly reported in phenylketonuria (PKU). In PKU, the metabolic pathway of phenylalanine is disrupted, which, among others, causes deficits in the neurotransmitters and sleep modulators dopamine, norepinephrine, and serotonin. Understanding sleep problems in PKU patients may help explain…

Sleep as part of a healthy lifestyle

What is sleep? Sleep as part of our daily life, This chapter describes the basic principles of sleep and wake regulation, the effects of sleep deprivation due to a mismatch between sleep and the biological clock, and what you can do about it. Every evening, a large behavioral change occurs in almost all people. In…

Educational paper published on Chronotherapeutic interventions

Chronotherapeutic interventions Marijke Gordijn of Chrono@Work co-authored a Dutch paper on Chronotherapeutic interventions in Psychiatry. She wrote this paper together with 3 colleagues with whom she also started Chronotherapy Network Netherlands (www.cnn.nl). The paper was published in the continuing education journal Psyfar. Since 2006, Psyfar focusses on educating and testing psychiatrists, hospital pharmacists, geriatrics specialists,…

Review paper on Seasonal affective disorder, winter type.

Seasonal affective disorder, winter type: current insights and treatment options Marijke Gordijn from Chrono@Work co-authored a review paper on Seasonal Affective disorders. Seasonal affective disorder (SAD), winter type, is a seasonal pattern of recurrent major depressive episodes most commonly occurring in autumn or winter and remitting in spring/summer. The syndrome has been well-known for more…

Sleep and need for recovery in shift workers: do chronotype and age matter?

This study examined associations of chronotype and age with shift-specific assessments of main sleep duration, sleep quality and need for recovery in a cross-sectional study among N ¼ 261 industrial shift workers (96.6% male). Logistic regression analyses were used, adjusted for gender, lifestyle, health, nap behaviour, season of assessment and shift schedule. Shift workers with latest versus earliest…

Human cellular differences in cAMP – CREB signaling correlate with light-dependent melatonin suppression and bipolar disorder

Various lines of evidence suggest a mechanistic role for altered cAMP-CREB (cAMP response element – binding protein) signaling in depressive and affective disorders. However, the establishment and validation of human inter-individual differences in this and other major signaling pathways has proven difficult. Here, we describe a novel lentiviral methodology to investigate signaling variation over long periods of…

The duration of light treatment and therapy outcome in seasonal affective disorder

Background: Seasonal affective disorder (SAD) is characterized by recurrent episodes of major depression with a seasonal pattern, treated with light therapy (LT). Duration of light therapy differs. This study investigates retrospectively whether a single week of LT is as effective as two weeks, whether males and females respond differently, and whether there is an effect of expectations as…

Effects of a chronic reduction of short-wavelength light input on melatonin and sleep patterns in humans: Evidence for adaptation

Light is an important environmental stimulus for the entrainment of the circadian clock and for increasing alertness. The intrinsically photosensitive ganglion cells in the retina play an important role in transferring this light information to the circadian system and they are elicited in particular by short-wavelength light. Exposure to short wavelengths is reduced, for instance, in elderly…

The biological clock modulates the human cortisol response in a multiplicative fashion

Human cortisol levels follow a clear circadian rhythm. We investigated the contribution of alternation of sleep and wakefulness and the circadian clock, using forced desynchrony. Cortisol levels were best described by a multiplication of a circadian and a wake-time component. The human cortisol response is modulated by circadian phase. Exposure to stress at an unnatural phase, as in…