Tiredness, sadness, pessimism are feelings that everyone suffers from time to time when they have too much duties, stress and worries. When a few bad events are happening at the same time one thinks that it is beyond his or her capabilities to deal with all of them, but after a short time life runs its normal course. Alas, failures together with continuous insomnia, anxiety and burnout intensify especially during the winter but sometimes also during other seasons. This result from the mood disorder called seasonal affective disorder. It is a state in which someone who may usually not have any problems with mental health will experience depressive symptoms. This disorder is very likely to affect life seriously while lasting for a long time. That is why it is important to know the major causes of winter blues to prevent its development. The major factors of SAD can be grouped into two types such as bad external conditions and changes in people's functionality.

The primary reason for winter depression is, as the name itself indicates, poor outside condition arisen from the winter. The worst feature of this season is unpredictable weather that is usually irritating and getting down when holding for a longer period of time. Excessive snowfall, low temperature and humidity are major things affecting people in a bad way. Lack of natural light is still another winter condition initiating SAD. The sky continuously covered with clouds and shorter days give rise to people's feeling sleepy more often and more quickly as well as having less enthusiasm for many things. Last but not least, bad weather is the primary factor of annoying road conditions and general outside difficulties. The public transport and services are paralyzed and that is why people face additional obstacles every day. The sequence of unlucky things with usual bad events occurring in the life cause that one may feel helplessness and suffer depression.

These all indirectly affective phenomena give rise to other more direct contributory factors to winter depression, which mostly affect one person's functionality. First of all, the bad weather conditions, especially low temperature, result in the high probability of illnesses such as flu, pneumonia, sinusitis, bronchitis. When one has faulty immune system and suffers illnesses like these few times during the winter, spends a lot of time at home, has backlog of work and is isolated from other people they are very likely to suffer from depression. Secondly, what is crucial is that the deficiency of the light during the day causes the higher level of melatonin in blood. This hormone is important as it is responsible for the regulation of sleep cycle. However if its amount is too big it leads to constant lack of energy, insomnia and in the end depression. What is more, low temperature and overall coldness lead to lower activeness. People may feel unwilling to go outside and meet with friends. They lack fresh air, light and there is likelihood of them feeling depressed.

There are many different causes of winter depression but they can generally be put into two categories, namely bad external conditions and changes in people functionality. The winter blues is very likely to disappear together with the season or shortly after the end of one's personal problems. Unfortunately, there are some people who cannot tackle with this state and without help their long lasting problems with mental health may lead to suicide. There is a great deal of SAD treatments such as medicines, light or behavioral therapies. A quick reaction for winter depression symptoms may be crucial for a sufferer so no one should ignore them.