Most of us feel happier in the warmer, lighter, summer months.

Seasonal affective disorder (SAD) describes how some can feel at the other end of the year. There is a spectrum, but at the more extreme end of that spectrum we see all the characteristic features of depression (low mood, irritability, lethargy, poor concentration, anhedonia…) but presenting in a seasonal pattern, usually through the winter. 

So, what is going on? The leading theory is that reduced exposure to sunlight interferes with the functioning of the hypothalamus, an important control centre within the brain.

We then see associated higher production of melatonin (the hormone that makes you sleepy), lower levels of serotonin (a hormone that affects mood, sleep, and appetite), and disruption of the body’s internal clock or ‘circadian rhythm’.

Things to try

Of course, with a little thought and effort we can also boost our exposure to natural sunlight. Making work and home environments as light and airy as possible and sitting near windows when indoors can make a difference to mood. Taking regular exercise outdoors and in daylight is ideal, but even a brief lunchtime walk is beneficial. A sunny holiday will lift some out of SAD, though might be offset by the guilt of your carbon footprint unless you swim there.

If all else fails though, at least it’s not long now until Spring!
Dr Chris Humphrey