How does our body know when to fall asleep? Should we avoid looking at our smartphones before going to bed? And what about eating late in the evening?

The SCRAMS project has created a comic book, ‘Enlighten your clock: How your body tells time’, to coincide with the UNESCO International Day of Light on Sunday 16th May. The book was illustrated by Coline Weinzaepflen, Masters student at the University of Strasbourg, and edited by Dr Manuel Spitschan at the Department of Experimental Psychology at Oxford. The team engaged with pupils, who provided feedback helping identify difficult concepts and fine-tune the book. The comic book provides a light-hearted, funny and scientifically grounded introduction to our biological clock, sleep, and how these are affected by the light we are exposed to. It is suitable for all readers from the age of 13 years.

Read the comic book.

 The main protagonist is a cat – a pet species notable for seemingly sleepy behaviour – guiding the human character. As the biological clock underlies many aspects of our physiology and behaviour, the book addresses a key need to explain how the environment impacts on our brain and our body.

Enlighten Your Clock promotional banner

Teenagers are not lazy! Experts address myths on World Sleep Day (19th March 2021)

It’s World Sleep Day – and experts from the Sleep, Circadian Rhythms and Mental Health in Schools (SCRAMS) network have come together to bust some myths and share some tips on teenage sleep. The pandemic has created many new challenges for teenage sleep, with most families reporting later bedtimes (and subsequent wake times) than ever before.

Myths about Teenage Sleep

Myth 1: Teenagers are lazy              

When teenagers struggle to wake up at the crack of dawn, this is not an indication of laziness – it reflects biological changes taking place. A shift in sleep timing during adolescence is found across the world, and is even found in other species such as the marmoset monkey. There might be good evolutionary reasons for this shift, such as encouraging young people to affiliate more with their peers and to move away from the family nest; or to allow societies to thrive (when members work on slightly different schedules someone is always alert to potential dangers). Ideally society should support this natural change in sleep timing, such as later school start times for teenagers. 

Myth 2: Biological patterns can’t be changed 

Although the shift in sleep timing during the teenage years is driven by biology, that does not mean nothing can be done. Lots of factors, such as the time we eat and exercise, can help tweak our biological clock to strike in time with the world around us. Light is critical for regulating sleep: healthy exposure to light in the morning (and avoiding light at night) can help to synchronise sleep rhythms. Those of us who already have delayed rhythms (such as almost all teenagers) should avoid light in the late evening. You may have seen the new trend of orange-tinted (blue blocking) glasses in adverts. Bearing in mind the science, they might be best kept to the end of the day when you want to wind down towards a good night’s sleep, and avoided in the morning when you want to rise and shine!

Myth 3: Try hard to get your 8 hours per night 

Lots of scientific reports suggest that we should not miss out on sleep if we want to function at our best. It’s important to allow ourselves enough time to sleep but we all differ in the amount of sleep needed. The idea that we all need exactly 8 hours of sleep each night is a myth. The National Sleep Foundation recommends that teenagers typically need about 8-10 hours of sleep each night (a minority will need as few as 7 hours and some as many as 11 hours). The idea that we must ‘try hard’ to sleep is also not true. Sleep at its best should be an automatic, natural and effortless process – ‘trying hard’ to sleep makes it particularly hard to nod off. What we should try harder with, however, is to make time for sleep when we feel we need it. 

Myth 4: A weekend lie-in is a bad idea

Sleep experts advise consistency when it comes to our sleep schedules. We should fall asleep and wake up at the same time each day. That is obviously fine if we have no commitments to get in the way. In reality, young people are often required to wake long before they are biologically ready to do so, and they may struggle to fall asleep early, meaning that most will be sleep deprived. So, some extra sleep at the weekend can help many young people to catch up. But be warned, too much of a lie in can also result in a shift in sleep timing referred to as ‘social jetlag’. This has been associated with poor concentration and feeling low. The weekend lie-in is not necessarily a bad thing so long as it’s taken in moderation.

For practical information about getting a good night’s sleep, see Sleep Scotland’s website. 

Download this information as a PDF.


Maurice Bloch Seminar 29 April 2020, School of Health & Wellbeing, University of Glasgow: 

Linda Geddes, Public Health Implications of the New Science of Sunlight

Linda Geddes is an award-winning British science journalist and author. She spent nine years working at New Scientist magazine as news editor, features editor and reporter, and remains a consultant to the magazine. Linda has received numerous awards for her journalism, including the Association of British Science Writers’ award for Best Investigative Journalism. Her most recent book “Chasing the Sun: The New Science of Sunlight and How it Shapes Our Bodies and Minds” explores the significance of sunlight, from ancient solstice celebrations to modern sleep labs, and the impact on public health of light-polluted cities and excessive exposure to bright lights from devices. This talk will focus on how public health can address exposure to light as an intervention to improve population health and wellbeing.

Journal articles

Shakoor, S; Zavos, Helena M. S.; Gregory, Alice M. and Ronald, A.  (2021). The association between bullying-victimisation and sleep disturbances in adolescence: Evidence from a twin study. Journal of Sleep Research, 00:e13321 (doi: 10.1111/jsr.13321)

Lyall, L. M., Sangha, N., Wyse, C., Hindle, E., Haughton, D., Campbell, K., Brown, J., Moore, L., Simpson, S. A., Inchley, J. C.& Smith, D. J. (2020) Accelerometry-assessed sleep duration and timing in late childhood and adolescence in Scottish schoolchildren: a feasibility study. PLoS ONE, 15(12), e0242080. (doi: 10.1371/journal.pone.0242080)

Madrid-Valero, J., J., Shakeshaft, N., Schofield, K., Malanchini, M., Ronald, A., Gregory, A.M. (2020). Sleep quality, insomnia and internalizing difficulties in adolescents: insights from a twin study.  Sleep. 43, zsz229.

Ghekiere, A., Van Cauwenberg, J., Vandendriessche, A., Inchley, J., Gaspar de Matos, M., Borraccino, A., Gobina, I., Tynjälä, J., Deforche, B. and De Clercq, B. (2019) Trends in sleeping difficulties among European adolescents: are these associated with physical inactivity and excessive screen time? International Journal of Public Health, 64(4), pp. 487-498. (doi: 10.1007/s00038-018-1188-1) (PMID:30535677)

Freeman, D., Sheaves, B., Goodwin, G.M., Yu, L-M., Nickless, A., Harrison, P.J., Emsley, R., Luik, A., Foster, R.G., Wadekar, V., Hinds, C., Gumley, A., Jones, R., Lightman, S., Jones, S., Bentall, R., Kinderman, P., Rowse, G., Brugha, T., Blagrove, M., Gregory., A.M., Fleming, L., Walklet, E., Glazebrook, C., Davies, B., Hollis, C., Haddock, G., John, B., Coulson, M., Fowler, D., Pugh, K., Cape, J., Moseley, P., Brown, G., Hughes, C., Obonsawin, M., Coker, S., Watkins, E., Schwannauer, M., Macmahon, K., Siriwardena, N., Espie, C.A. (2017). The effects of improving sleep on mental health (OASIS): a randomized controlled trial with mediation analysis. Lancet Psychiatry, 4, 749-758.

Gregory, A.M., Agnew-Blais, J.C., Matthews, T., Moffitt, T.E., & Arseneault, L. (2016). ADHD and sleep quality: Longitudinal analyses from childhood to early adulthood in a twin cohort. Journal of Clinical Child and Adolescent Psychology, Special Issue on Sleep, DOI: 10.1080/15374416.2016.1183499

Gregory, A.M., Sadeh, A. (2016). Annual Research Review: Sleep problems in childhood psychiatric disorders: A review of the newest science. Journal of Child Psychology and Psychiatry, 57, 296-317  

Cecil, C., Viding, E., McCrory, E., Gregory, A.M. (2015). Distinct mechanisms underlie associations between forms of childhood maltreatment and disruptive nocturnal behaviours. Developmental Neuropsychology,Special Issue on Pediatric Sleep, 40, 181-199.                          

Greene, G., Gregory, A.M., White, J., Fone, D.(2015). Childhood sleeping difficulties and depression in adulthood: The 1970 British Cohort Study. Journal of Sleep Research, 24, 19-23.

Taylor, M., Gregory, A.M., Freeman, D., Ronald, A. (2015). Do sleep disturbances and psychotic experiences in adolescence share genetic and environmental influences? Journal of Abnormal Psychology, 124, 674-684.

Willis, T.A., Gregory, A.M. (2015). Anxiety disorders and sleep in children and adolescents. Sleep Medicine Clinics, 10, 125-131.

Goldman-Mellor, S.J., Gregory, A.M., Caspi, A., Harrington, H-L., Parsons, M., Poulton, R., Moffitt, T.E. (2014). Mental health antecedents of early midlife insomnia: Evidence from a four-decade longitudinal study. Sleep, 37, 1767-1775.

Noone, D.M., Willis, T.A., Cox, J., Harkness, F., Ogilvie, J., Forbes, E., Sterr, A., Gregory, A.M. (2014) Catastrophizing and poor sleep quality in early adolescent females, Behavioral Sleep Medicine, 12, 41-52.


Adolescents’ screen time, sleep and mental health: literature review.

Research team – Chief Investigators: Dr Anne Martin, Dr Juliana Pugmire, Co-Investigators: Valerie Wells, Julie Riddel, Dr Christina McMellon1, Dr Kathryn Skivington, Prof Sharon Simpson, Prof Lisa McDaid. 

Published by the Scottish Government, February 2020.


Gregory, A.M. (2018). Nodding Off. Sleep from Cradle to Grave. Bloomsbury Sigma, London.

Gregory, A.M. & Kirkpatrick, C. (2019). The Sleepy Pebble and Other Stories: A book to help children relax before bedtime. Flying Eye Books.