For many people, the run-up to Christmas is filled with excitement and anticipation. For others, it can quietly tip into something more difficult. A drop in mood is particularly common after Christmas, especially in the final week of the year and the first days of the new one. Understanding why this happens can help make that emotional dip easier to manage.
The post-Christmas blues are closely linked to the brain’s reward system. Neurotransmitters are chemical messengers that allow brain cells to communicate with each other and play a key role in how we feel, think and behave. One of the most important of these is dopamine, which helps regulate motivation, pleasure and reward, and is often targeted by antidepressants.
During the festive period, dopamine levels tend to rise. Anticipation of celebration, time spent with others, indulgent food and festive rituals all stimulate this feel-good system. Compared with everyday life, the brain experiences a powerful boost. Even thinking about Christmas before it arrives can activate these pathways, creating a surge of sensory excitement.
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Once Christmas is over, dopamine levels naturally fall back to their usual baseline. This sharp contrast between heightened stimulation and everyday routine can leave people feeling flat, unmotivated or low. This is the familiar post-Christmas slump.
Another hormone involved is oxytocin, often referred to as the “love hormone”. Oxytocin supports social bonding and emotional connection. It rises when we experience closeness, such as when a parent hugs their child, helping to strengthen feelings of trust and attachment. Christmas often involves more time with family and loved ones, which can increase oxytocin release.
After the holidays, however, that intensity of connection often drops away. When shared meals, visits and quality time suddenly decrease, oxytocin levels may fall too. This shift can contribute to feelings of loneliness, emotional emptiness, or low mood.
Who we spend time with over Christmas also matters. Not everyone at the table evokes comfort or closeness. Research suggests that time spent with in-laws, for example, may be more stressful than time spent with one’s own family. In these studies, changes in gut microbiota suggested higher stress responses when people spent time with in-laws over the holidays. This highlights that not all social interactions have the same emotional or physiological effects.
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From a psychological perspective, positive experiences during the festive season are often linked to greater social connection, bursts of positive emotion and higher life satisfaction. Gift-giving can also create a surge of positive emotions and even improve cognitive functioning, but only when it goes well.
Choosing gifts for people we care about often comes with high expectations. When a gift is poorly received or feels disappointing, neuroscientific evidence shows that givers may experience emotional pain similar to social rejection. This is why expressions of gratitude matter. Even when a gift misses the mark, appreciation helps protect the emotional wellbeing of the giver.
Christmas also disrupts everyday routines. Later nights, overeating and increased alcohol consumption are common. All of these affect sleep quality, which is closely linked to mood and emotional regulation. When sleep is disturbed, people are more vulnerable to low mood, making the post-Christmas period feel even harder.
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So how can you protect your wellbeing?
Start by noticing how your environment affects you. Recent research suggests that protecting mental health begins with recognising situations and interactions that drain or distress you. If this happens during family gatherings, it can help to step away, disengage from tense conversations, or take short breaks to reduce emotional strain.
If you are spending Christmas alone and festive surroundings intensify feelings of sadness, it is reasonable to limit your exposure. Choose activities and places that genuinely comfort you, and reduce unnecessary reminders that worsen your mood. Setting boundaries, taking time out and disengaging from emotionally draining interactions are valid forms of self-care.
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Re-establishing your usual routine as soon as possible can also help. Returning to regular bedtimes and wake times supports your circadian rhythm and helps your body regain a sense of normality. Exposure to daylight soon after waking is especially useful, as natural light signals to the brain that the day has begun. A short walk around midday, when light levels peak, can further support energy and mood.
Finally, create an “after Christmas” plan. Scheduling small activities, social connections, or goals gives you something to look forward to and softens the emotional contrast between the festive season and everyday life. Practising presence and finding small moments of enjoyment each day can also help restore balance.
If you feel low after Christmas, it is not a personal failing. It is your brain and body responding to the emotional, social and sensory intensity of the season. By understanding what is happening, you can soften the post-Christmas crash and support your wellbeing. Christmas ends, but its emotional echoes do not have to overwhelm the weeks that follow.
Jolanta Burke does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
