One of the topics discussed at a recent meeting of the British Psychological Society is of particular interest at this rather dismal time of year. Psychiatrists have recognised for some 15 years that there is a mental condition, known as seasonal affective disorder (SAD), associated with darker days and longer nights. It has been assumed that memory, attention and power of concentration are diminished in winter. However, doubt has been thrown on this assumption by work carried out in the university of Tromsø, where the conditions within the Arctic Circle mean that the sun is seen continuously for two months in summer and is lost for two months in winter.
Standard tests for attention lapses, impaired memory and slow or confused thinking among Tromsø residents were carried out in December and June. Most results showed that cognition was roughly similar at both times, but that in four of five tasks in some subjects it improved in December. It is true that some 10 per cent of the population demonstrated some degree of depression, but the experiments involved a sample of the general population and did not concentrate on the exceptions.
It appears that persons suffering from SAD may still be slower in reaction times, more liable to lapses of memory, and less acute mentally. Further investigation of the phenomenon is desirable, if only to assess the possibility of a higher vehicular accident rate in midwinter.