More than 5,000 Lincolnshire people are estimated to be suffering from depression this winter due to lack of daylight.

Going to work in the morning in the dark and then leaving when it is dark is enough to get anyone down.

But when a person actually sinks into clinical depression it is called Seasonal Affective Disorder (SAD).

Dr Mick Eames, GP at The Surgery in Market Rasen, said he has patients who have recognised and coped with the affliction by going on antidepressants during the winter months to treat the seasonal depression.

Meanwhile others rely on light boxes – which can be purchased for around £100 from stores including Boots – to boost the hours of natural light they are receiving each day.

"I never want to put the idea of SAD in people's heads but sometimes you do pick up a pattern after two or three winters of depression," said Dr Eames.

Meanwhile Dr Carol Brady, general manager for psychological therapies at Lincolnshire Partnership NHS Foundation Trust, said the peak age for the onset of SAD is from 18 to 30 years.

"Although SAD affects seven per cent of the population there are many more people who get the winter blues and feel like hibernating during the cold," said Dr Brady.

"But SAD is a chemical imbalance present in all depression which is caused by a lack of daylight and how this impacts on us.

"And the thing with SAD is that it can't necessarily be helped by psychological therapies as it's a case of some people reacting quite badly to a shortage of daylight.

"When spring comes there is a marked change in them whereas a person suffering from 'regular' depression would be the same at any time of year."