As the clocks have quietly gone back, you may notice that it's getting dark earlier and the evenings feel longer. For some people, this may bring a noticeable dip in mood and energy. It might feel harder to get out of bed in the morning; you might want to stay indoors more, and for some people, they may feel their mood is flatter than usual. Many people feel lower in mood and energy as they adjust to the change in seasons (Age UK, 2026), and for most, it eases as the days lengthen again.

However, for some people, the darker months can bring something heavier. Below, I look at how to tell the difference between the “winter blues” and seasonal depression, what the research says about what helps, and when it's worth seeking support.

Winter blues or something more?

Seasonal affective disorder (SAD) is a type of clinical depression that usually affects your mood during the winter months and lifts as the summer approaches. Symptoms can include low mood, losing interest in things you usually enjoy, and feeling guilty, irritable, hopeless or worthless. Some people also notice they may feel more tired and sleep more than usual and can become hungrier and eat more or find it hard to concentrate (NHS, 2025).

It's not fully understood what causes SAD, but it's likely to be a combination of factors. A current suggestion is that the causes of SAD are similar in nature to the causes of depression, but some specific factors and changes can lead to it specifically. SAD is thought to be linked to reduced daylight in winter. When light enters the eye and reaches the retina, it sends messages to the parts of the brain known to be responsible for sleep, appetite and mood. This may affect brain chemicals such as melatonin and serotonin, which influence mood and sleep (Mind, 2025).

The difference between the winter blues and SAD is mainly one of severity and pattern. You may be diagnosed with SAD if you have had depressive symptoms at a particular time of year for at least two years and depressive episodes during the specific season are more frequently experienced than at other times of the year. Because the pattern only shows itself over time, it can take several years to recognise (NIMH, 2023).

What the statistics show

If the darker months affect you, you're certainly not alone. In a YouGov survey of over 2,000 adults in Great Britain, more than half (56%) reported that their mood tends to be worse during the winter months, compared with just 6% who feel their mood improves (YouGov, 2024).

For some people, this change can be more than a temporary dip in mood. Rethink Mental Illness estimates that around 1 in 15 people in the UK experience symptoms of SAD, with approximately 3 in 100 people being severely affected (Rethink Mental Illness, 2026). However, estimates can vary between studies, partly because the distinction between the winter blues and SAD isn't always clear-cut.

SAD can go unrecognised for some time. A study in North Wales found that most people who met the criteria for SAD had never been diagnosed with it (Michalak et al., 2001). Similarly, a large UK study of more than 150,000 adults found that women were more likely to experience low mood and a loss of enjoyment in daily activities as the days grew shorter (Lyall et al., 2018).

If any of this sounds familiar, know that it is not a personal failing or something you just have to put up with. It is a common response to the change in seasons, and there are many things that can help.

What can help?

Get outside in daylight

The NHS recommends getting as much natural daylight as you can, ideally going outside in the daytime every day, as well as getting regular exercise (NHS, 2025). Another option is ecotherapy, which is the practice of being in nature for its therapeutic benefits. This therapy can be self-administered through outdoor activities such as gardening, volunteering outdoors, or just being in the great outdoors. Ecotherapy can be experienced more formally as part of a treatment plan with a qualified professional (King Edward VII's Hospital, 2023). Try increasing your time spent outdoors gently through options such as a lunchtime walk, parking one street further away, or getting off the bus a stop early; all can help.

Stay connected

When the evenings are dark and cold, it's tempting to cancel plans and stay in. Low mood can compound this further, as socialising may feel overwhelming. Taking steps to stay in contact with friends and family, even if it's a phone call, can have beneficial effects on mood (Royal College of Nursing, 2025). If keeping in touch is difficult, local community groups and befriending services can offer connection.

Keep doing the things that matter to you

Low mood tends to make us withdraw, and withdrawing can compound low mood further. A form of cognitive behavioural therapy (CBT) developed specifically for winter depression encourages people to resist this cycle by planning enjoyable or meaningful activities rather than waiting until they feel like it (Rohan et al., 2015).

The winter months can also be a time to try that new hobby that you've been procrastinating about. Starting a new hobby, whether it's art, music, gardening or any other interest you may have, helps build routine and can help distract from the symptoms of SAD and provide you with a sense of accomplishment (TherapyForYou, 2023).

Notice your thoughts about winter

It's common to dread the winter months before they arrive, with thoughts like “I always feel awful in winter” or “there's nothing to look forward to until spring”. Research suggests that gently questioning these beliefs may be part of what helps people stay well in future winters (Rohan et al., 2023).

What about vitamin D?

The government advises that everyone should consider taking a daily vitamin D supplement of 10 micrograms during autumn and winter, because the sun isn't strong enough for our bodies to make it (NHS, 2023). This advice is about general health, particularly bones and muscles, rather than a treatment for low mood.

Light boxes

Some people use a light box, which is a lamp that gives off very bright light, for a set time each morning. A review of 19 trials found light therapy worked better than a placebo for SAD, although the studies were small and varied in quality (Pjrek et al., 2020). Light therapy isn't usually available on the NHS because of uncertainty about the evidence, but many people find it helps. If you do consider buying one, the NHS advises choosing one that is bright enough (10,000 lux is standard), UV-free and UKCA or CE marked (NHS, 2025). It's worth talking to your GP first.

How talking therapy can help

Talking therapies are an effective treatment for SAD. Cognitive Behavioural Therapy (CBT) has been shown to be effective in treating SAD. This type of cognitive therapy involves meeting regularly with a professional to explore how you think about a situation and what feelings arise as a result. This allows the exploration of alternative ways of thinking and behaving which could be more useful (Mental Health UK, 2022). In a large trial, CBT adapted for winter depression worked as well as light therapy during the winter it was given (Rohan et al., 2015). When participants were followed up two winters later, fewer of those who had CBT had become depressed again, around 27% compared with 46% (Rohan et al., 2016).

These studies looked at a specific form of CBT, rather than a range of therapeutic approaches; however they still indicate that understanding your own thought patterns and having a plan for the darker months, can make the next winter feel more manageable.

When to get help

The NHS advises seeing a GP if you think you might have SAD and are struggling to cope, or if you have been diagnosed and treatment isn't helping (NHS, 2025). In England, adults can also refer themselves to NHS Talking Therapies without seeing a GP.

If you notice the same dip in mood happening year after year, it can help to start planning in early autumn, before things get difficult.

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