If you think seasonal changes don’t affect us adversely, you may be among an increasingly small number of people who hold that perception. We now know that climate change is bringing on changes we failed to see in our growing concern for how it is affecting the realities of life in general in terms of our livelihoods.
Studies have shown that changes in the weather have a greater effect on our emotions and mental health than they usually do. During the dark season, some people experience what is known as “winter depression,” or seasonal affective disorder (SAD). This condition involves not just the usual depressive symptoms but also increased appetite, weight gain, and excessive sleepiness, which results in longer sleep duration and fatigue during the day. While it may leave us feeling grumpy or a bit less usual to skate through emotional ups and downs, it is becoming more of a problem for industry and social relationships.
One study in Finland accessed records for sick days taken over twelve years with nearly 700,000 people’s data. The results were nothing short of eye-opening for researchers who wondered if climate change truly was affecting our mental health.
A review of the data revealed that manic episodes reached a peak from March to July and dipped in September–November and in January–February; unipolar depressive disorders peaked in October–November and dipped in July, with similar associations in all forms of depression; anxiety and non-organic sleep disorders peaked in October–November; anxiety disorders dipped in January–February and in July–August, while non-organic sleep disorders dipped in April–August. Seasonality was not dependent on the severity of the depressive disorder. Researchers then began to look at patterns of light exposure.
The findings from Norway, which suggest brighter summers and darker winters, can help clinicians and workplaces prepare for seasonal variations in healthcare needs. The results suggest a seasonal variation in sick leave due to common mental disorders and bipolar disorder, with high peaks in depressive, anxiety, and sleep disorders towards the end of the year and a peak in manic episodes starting in spring. Rapid changes in light exposure may have an impact on bipolar disorder-related sick leave.
Variations in circadian rhythms are likely to prominently mediate these seasonal effects since light strongly entrains the internal clock, modifying brain function. Seasonality patterns are reported in a variety of psychiatric disorders. Brain adaptations associated with seasonal changes, factors that contribute to individual differences, and their implications for psychiatric disorders are all being studied.
The availability of light has an impact on serotonin, a neurotransmitter that is essential for happiness and mood regulation. Photoperiodic adaptation of the human brain’s circadian system may be the cause of changes connected to sunrise and sunset timing. If we have more gloomy days than light ones, it stands to reason that our mood may be affected.
I once had a clinical supervisor who wrote his dissertation on the effect a specific season of clouding fog in Switzerland had on the emotions of the people in that particular region—and this was well before we began to understand SAD and reading public were introduced to the concept.
While social influences and pressures associated with the season, such as holidays and school schedules, can influence symptoms, strong evidence indicates that biological processes are a major contributor to the observed seasonality. If birds are pushed to migrate by light hitting a small area in their brain behind a delicate bone near the beak, we aren’t very different. We may not migrate, but we do change our moods and behaviors.
But changing light conditions aren’t the only way climate change is increasing mental health issues. Children are often very resilient, and their reactions to disasters may resolve over time, but they should be monitored for the long-term effects of chronic stress. Other factors that contribute to children’s distress include disruptions in routine, separation from caregivers as a result of evacuations or displacement, and parental stress following a disaster.
How much thought has been given or action taken relative to climate change in addition to mood changes? Lack of rain and erratic weather patterns also contribute. Forest fires contribute to pollution, which can also carry environmental pollutants from burning structures. Air pollution has been shown to increase the risk of autism, lower cognitive ability, and cause more ADHD and behavioral problems in children, as well as increase the risk of dementia, particularly Alzheimer’s dementia, in adults.
While there are many other sources of air pollution, the use of fossil fuels accounts for 85 percent of all air pollution. This particulate air pollution can travel to the brain in the blood vessels and in nerve cells, where it causes inflammatory cell damage. We already know that depression is probably associated with some degree of inflammation.
It’s not about weather changes; it’s about major health concerns that will only increase as our Earth is scorched and resources are lost.