Winter low mood or SAD? When it’s more than the season

Many people feel more tired and a little lower in winter, and that is not necessarily a sign of anything wrong. Seasonal affective disorder (SAD) is different: the NHS describes it as a type of depression that usually happens in winter and tends to ease in summer. The Royal College of Psychiatrists draws the line at impact. If your mood, energy and sleep are changing enough to interfere with daily life, it may be more than the season, and it is worth talking to your GP.

Key points

• SAD is a type of depression with a seasonal pattern, most often in winter.
• Common signs include low mood, losing interest in things you usually enjoy, eating more, and feeling more tired and sleeping more than usual.
• The causes are not fully understood, but reduced daylight is thought to play a part.
• The NHS lists talking therapies such as CBT, antidepressants and light therapy as treatments.
• In England you can self-refer to NHS Talking Therapies; your GP can also help.

What is seasonal affective disorder?

Seasonal affective disorder, often shortened to SAD and sometimes called winter depression, is depression that returns at a similar time each year. For most people with SAD this is the autumn and winter months, although the NHS notes that some people have symptoms in summer instead.

The Royal College of Psychiatrists estimates that around 3 in 100 people in the UK have significant winter depression, and says it is more common in women than in men. Many more people notice milder seasonal changes, such as feeling sluggish or wanting to stay in more, without it amounting to depression.

How do I know if it’s SAD or just the winter blues?

There is no simple test you can do at home, and only a health professional can make a diagnosis. But some questions may help you reflect on what you are experiencing:

• Is your low mood there most of the day, on most days, rather than coming and going?
• Have you lost interest or pleasure in things you usually enjoy?
• Are you struggling to keep up with work, relationships or looking after yourself?
• Do you notice the same pattern returning at around the same time each year?
• Are you having thoughts that you are worthless, that things are hopeless, or of harming yourself?

The NHS lists symptoms of SAD including low mood, a lack of interest in things you usually enjoy, feeling guilty, hopeless or worthless, feeling restless or irritable, difficulty concentrating, feeling hungrier and eating more than usual, and being more tired and sleeping more than usual. Some people also have thoughts of suicide or self-harm. The Royal College of Psychiatrists notes that sleeping and eating more, and craving carbohydrates, are more typical of SAD than of most other depression.

According to the NHS, SAD may be diagnosed if symptoms of depression come back at the same time of year for at least two years. If your mood is low but you are not sure whether there is a seasonal pattern, it is still worth seeking support. You do not need a label to deserve help.

What causes winter depression?

The exact causes of SAD are not fully understood. The NHS explains that it is thought to be linked to reduced exposure to sunlight in the shorter days of autumn and winter. Less light may affect the production of melatonin, a hormone involved in sleep, and serotonin, a chemical involved in mood, and may disrupt the body’s internal clock.

Light is unlikely to be the whole story. The Royal College of Psychiatrists points out that people living in the far north do not have higher rates of SAD, which suggests other factors play a part. Winter can also bring its own pressures, such as fewer chances to get outside, less social contact, financial strain, and anniversaries or festive seasons that are hard for some people.

What can I do to help myself?

Self-help will not replace treatment if you are depressed, but small, steady changes can make a difference to how winter feels. The NHS suggests:

• Getting as much natural daylight as you can, ideally by going outside each day, even when it is cloudy.
• Getting regular exercise.
• Staying in touch with friends and family, even when you feel like withdrawing.
• Keeping up your usual activities, even in smaller doses.
• Going to bed and waking up at around the same time every day.
• Not drinking too much alcohol, and avoiding phones and other screens right before bed.

It can also help to plan ahead. If you know winter tends to be hard, you might arrange things to look forward to, let people close to you know what you are going through, and notice early signs that your mood is dipping. If stress and exhaustion are part of the picture, my page on stress and burnout may also be useful.

Does light therapy work for SAD?

Light therapy involves sitting in front of a special lamp, often called a light box or SAD lamp, that gives out a bright light similar to daylight. The Royal College of Psychiatrists says there is some evidence for it and that side effects are usually mild. However, the NHS says light therapy is not usually available on the NHS because there is not enough evidence about whether it works, although many people find it helpful.

The NHS recommends speaking to your GP before trying light therapy, as it may not be suitable if you have certain eye conditions or take medicines that make you more sensitive to light. If you do buy a lamp, the NHS suggests choosing one that gives about 10,000 lux, does not give off UV light, and has a UKCA or CE mark.

When should I see a GP about low mood in winter?

The NHS suggests seeing a GP if you think you might have SAD, or if you have been diagnosed and your treatment is not helping. Your GP can talk through how you have been feeling, check for anything else that could be contributing, and explain the treatment options, which include talking therapies and antidepressants. Medication is a decision to make with your GP; as a psychotherapist, I do not prescribe or advise on medication.

In England, if you are 18 or over (or 16 or over in some areas), you can refer yourself to NHS Talking Therapies without seeing your GP first. The Royal College of Psychiatrists notes there is some evidence that CBT can help with SAD and may reduce the chance of it returning in future winters.

How can therapy help with winter low mood?

Therapy can offer a regular, steady space during months that can feel long and isolating. It can help you notice the patterns in your mood, understand what tends to make things harder or easier, and look at anything else that may be adding to the weight, such as loss, loneliness, work pressure or the expectations of the festive season.

I am an integrative psychotherapist registered with the BACP, drawing on person-centred, psychodynamic and CBT-informed ideas. You can read more on my page about depression. I see adults in Farringdon, Central London, and offer online counselling by secure video, which some people find easier on dark winter days.

If you are in crisis, call 999, go to A&E, call NHS 111, or contact Samaritans on 116 123 (free, 24/7).

If winter is weighing on you and you would like to talk it through, you are welcome to get in touch to arrange an initial consultation. There is no need to be sure whether it is SAD before reaching out.