Depression Turned Out To Be Closely Related To the Season

The SAD light we sold make me know more about depression, which has been turned out closely related to the season. Listen to the interpretation of psychologists and stay away from SAD.

From a seasonal perspective, depression tends to occur more frequently in autumn and winter. As the Chinese saying goes: “Autumn wind and rain are sorrowful”, the meaning of sad autumn has also begun to affect people’s emotions to a certain extent.

However, with the in-depth study of depression, it is inevitable to judge which season has a high incidence from the perspective of climatic factors. At the same time, many research results show that the combined effect of temperature and light in different latitudes on depression There is also a certain correlation between the incidence of disease.

What Is Seasonal Affective Disorder (SAD)?

For many people, the climate changes throughout the year will also change their moods. Simply understand:

  1. In the spring, everything recovers, and people are full of hope;
  2. In summer, although the heat is unbearable, what people enjoy in their hearts is hearty and a hint of coolness;
  3. In autumn, the chill slowly hits, and people feel a little sad in their hearts;
  4. In winter, snow in the sky is not only physically unsuitable, but also more likely to bring “psychological flu.”

To explain from a scientific perspective, seasonal affective disorder is a psychological concept first proposed by Rosenthal in 1984.

This affective disorder usually starts to recur in late autumn every year, and most of them are accompanied by the following symptoms:

  • Lack of energy, easy to get sleepy
  • Feel weak and not interested in many things
  • Increased appetite, weight gain
  • Emotional ups and downs, irritable and easily depressed
  • Insomnia, anxiety, restlessness, etc.

These symptoms continue until winter and spring alternate. This symptom is called SAD, seasonal affective disorder, or winter depression.

Geographical Factors On Seasonal Affective Disorder

From the perspective of geography, the salient characteristics of seasonal affective disorder have also been discovered. In summary:

  • SAD is prominent in the north of 30 degrees north latitude or south of 30 degrees south latitude;
  • In low latitude areas, even if SAD exists, the symptoms are mild;

To explain these two items in a simple and understandable way, they can be summarized as:

1. The area north of 30 degrees north latitude in China refers to the area north of the Yangtze River Basin, such as Hubei, Zhejiang, Shandong, Anhui, Gansu, Shaanxi, Shanxi, Henan, Inner Mongolia, Hebei, and the three provinces of East China.

These provinces generally have distinct four seasons in terms of climate, and are the provinces with more prominent seasonal affective disorder symptoms.

2. Low-latitude regions include Guangdong, coastal cities in Guangxi, and Hainan Province in China.

For low-latitude regions, due to the climate in summer most of the year and the small temperature difference between day and night throughout the year, seasonal affective disorder, even if it exists, has much milder symptoms than people in the north of the Yangtze River.

Corresponding scientific basis:

Among them, the University of North Greenland has made a corresponding study. They have moved people in high latitudes with cold climate and long winters to low latitudes, and seasonal affective disorder has been well alleviated.

What Is The Cause Of Seasonal Affective Disorder?

In the field of clinical psychology, it is recognized that the main factor that causes seasonal affective disorder is “length of light.”

At the same time, two points of view of the famous Japanese psychologist Sakamoto are also quoted to prove that the argument of “light duration” is sufficient and reliable:

  1. The higher the north-south latitude is, the higher the incidence of seasonal affective disorder;
  2. By supplementing artificial light, the symptoms of a considerable number of SAD patients can be relieved;

Finally, after in-depth research, in 1980, American psychiatrist Professor Lewy and others also confirmed for the first time that the human biological clock has light-sensing characteristics, that is, the length of light is positively correlated with the secretion of melatonin in the body.

Therefore, in 1981, Professor Lewy used artificial lighting to treat depression, and achieved good results with SAD seasonal affective disorder, and accumulated a lot of experience.

What Is The Relationship Between Melatonin And Depression?

Anyone who has taken an international flight should know that jet lag is a very tormenting thing.

The reason for it is that because of the light, it has changed our normal biological clock. Give a simple example:

You take an international flight from China to the other side of the earth. When you take off, China is in the evening. After 20 hours of flight, according to the original biological clock, it is basically time to sleep again, but this country is still In the sunny morning, under the influence of light, the secretion of melatonin is inhibited, the biological clock wants to sleep very much, but the body is extremely excited.

This is the relationship between melatonin and light.

At the same time, friends who have depression patients should be very aware that people with depression are very resistant to contact with things and people in the outside world, not to mention that they are willing to take outdoor walks every day.

Then, the light received indoors will be much lower than that of the outdoor environment, the secretion of melatonin will increase, and the level of melatonin will continue to increase, people will feel drowsy and unable to relax.

This is why people in low latitudes receive much longer light than people in high latitudes, and seasonal affective disorder is not easy to occur.

Are People In Low Latitudes Less Prone To Depression?

This returns to the partial generalization at the beginning. If we only talk about depression under seasonal affective disorder from climatic factors, it is indeed a partial generalization, and then we must also judge by considering the latitude factors in geography.

Combined with the domestic research on Shenzhen by Professor Yan Jingqin and others experts, another hidden veil of climatic factors and depression was discovered.

Shenzhen, as a special economic zone at the southern tip of China, has an annual average temperature of more than 20 degrees, and sunshine duration is also among the best in China.

According to the previous overview, the probability of people in Shenzhen suffering from seasonal affective disorder is much lower than that of people in other regions, and the prevalence of depression should also be reduced.

However, after combining Professor Yan’s research, it was found that the answer was not the case. According to the clinical data of depressed patients in Shenzhen, there was an extra summer admission peak period compared to the area north of the Yangtze River, and this peak period was in other regions. No.

Finally, it was stated in the research conclusion that the reason is that Shenzhen has a subtropical ocean monsoon climate. Unlike the area north of the Yangtze River, which has obvious seasonal changes with four distinct seasons, summer is a rainy season, with high temperature, high humidity, and no gradient of seasonal changes. , Is another reason for the high incidence of summer depression.

How To Avoid Seasonal Affective Disorder (Winter Depression)?

Since depression is due to lack of light, use light to treat depression accordingly.

  1. No matter which latitude of the city you live in, you must properly receive the sunshine. Office workers who are often indoors can be treated with daylight lamps. Only by receiving more light can the secretion of melatonin in the body during the day be inhibited, which can effectively relieve the mood of depression;
  2. People in the area north of the Yangtze River should actively go outside for activities in autumn and winter.
    Although the weather gradually turns cooler in autumn and winter, more outdoor exercises should be added to not only strengthen the body, but also supplement the mild sunlight in autumn and winter;
  3. For people in coastal cities in Guangdong and Guangxi, although they have sufficient daylight, they should pay attention to another kind of damage caused by high temperature and high humidity.

At the same time, for the cliff-like summer and winter alternates in southern coastal cities, we must adapt our body to this peculiar climatic characteristic as soon as possible, so as to prevent the occurrence of seasonal affective disorder.


Regarding depression, the factors that can affect it are numerous and complex, and it cannot be used for a certain season to have a high incidence and a certain latitude to have a low incidence. Let’s make a partial summary. Combining your own different symptoms, actively making changes in your life is the right thing to do. Embracing the sun more and exercising more outdoors will only benefit people who are depressed.

For people in countries where polar night occurs, it is recommended to use a SAD therapy lamp regularly and artificially supplement the light, so that reduce the incidence of depression.

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