NATALIJA HAYTERPSYCHOTHERAPY & COUNSELLINGFor some people, low mood arrives on a schedule — deepening through autumn and winter, lifting in spring. This is seasonal affective disorder, or SAD, and it is more than simply disliking dark evenings.
What it is
SAD is a form of depression that follows a seasonal pattern, most commonly worsening in winter. Reduced daylight is thought to disrupt the body clock and the brain chemicals that regulate mood and sleep. The symptoms are those of depression — low mood, low energy, loss of interest — often with a particular tendency to oversleep and crave carbohydrates.
What helps
Light therapy — daily exposure to a specialised lightbox — has good evidence for winter SAD. Getting outside in natural daylight, especially in the morning, helps. And because SAD is a genuine depression, talking therapy works too: CBT adapted for SAD addresses the thoughts and behaviours that deepen the winter dip. If your low mood is reliably seasonal, it is worth treating, not just enduring until spring.
This article is for information and is not a substitute for professional advice or diagnosis. In an emergency call 999, NHS 111 (option 2), or the Samaritans free on 116 123.
Natalija Hayter is a BABCP-registered psychotherapist with over a decade of clinical experience across the NHS, the voluntary sector and private practice, trained at the Tavistock and AGIP. She offers CBT, psychoanalytic and relational therapy in Pimlico, London and online, in English, Latvian and Russian. More about Natalija
Last reviewed: June 2026 by Natalija Hayter, BABCP-registered psychotherapist.