December 14, 2021 - Serotonin levels. A drop in serotonin, a brain chemical (neurotransmitter) that affects mood, might play a role in SAD. Reduced sunlight can cause a drop in serotonin that may trigger depression.

SAD is a type of depression that happens during a certain season of the year, most often fall and winter. There is no clear cause of SAD. But less sunlight and shorter days may be part of the cause.

The main symptom of seasonal affective disorder (SAD) is depression that happens in the winter and goes away in the summer.

In contrast, people with summer-pattern SAD may have reduced melatonin levels, consistent with long, hot days worsening sleep quality and leading to depression symptoms. Longer daylight hours, shorter nights, and high temperatures can also cause sleep disruptions.

July 14, 2025 - Light therapy can then cause harm. Have bipolar disorder: Bright light therapy and antidepressants can trigger hypomania or mania, uncontrolled boosts in mood and energy level. If you have bipolar disorder, let your provider know. This will play a role in your treatment plan. ... Irritability. Don’t use tanning beds to treat SAD.

October 31, 2025 - That’s because “it may not necessarily be seasonal affective disorder,” Dr. Ambrose said. “The etiology, the root cause behind your symptoms, may not necessarily be the circadian rhythm changes or the reduced light exposure.

April 14, 2025 - Seasonal Affective Disorder (SAD) is a form of depression that typically occurs during the fall and winter months due to reduced sunlight exposure. This change disrupts the body’s natural rhythms, lowers serotonin levels, and increases melatonin ...

October 16, 2024 - While the exact cause is unknown, it may be linked to the reduced amount of sunlight affecting the natural chemicals like serotonin and melatonin in your body that determine mood and energy levels and regulate sleep.

They may ask you about your mood, ... of SAD is not fully understood, but it's often linked to reduced exposure to sunlight during the shorter autumn and winter days....

1 week ago - One possibility is that SAD is related to a lack of serotonin, and serotonin polymorphisms could play a role in SAD, although this has been disputed. Mice incapable of turning serotonin into N-acetylserotonin (by serotonin N-acetyltransferase) appear to express "depression-like" behavior, and antidepressants such as fluoxetine increase the amount of the enzyme serotonin N-acetyltransferase, resulting in an antidepressant-like effect. Another theory is that the cause may be related to melatonin, which is produced in dim light and darkness by the pineal gland, since there are direct connections, via the retinohypothalamic tract and the suprachiasmatic nucleus, between the retina and the pineal gland.

Many of us are affected by the changing seasons. The colder weather and darker evenings can affect our mood, energy levels, sleeping patterns, and appetites. But if this affects your daily life, you may have Seasonal Affective Disorder (SAD).

October 11, 2024 - It’s thought that people with SAD release more melatonin earlier in the day making sufferers feel sluggish and low. Serotonin helps to regulate our mood and is often referred to as a happy hormone. A reduction in sunlight can cause levels of serotonin to drop, leading to a low mood and other SAD symptoms.

Lack of light may upset your "biological clock," which controls your sleep-wake pattern and other circadian rhythms. Lack of light may also cause problems with serotonin, a brain chemical that affects mood. Seasonal affective disorder (SAD) can come and go at about the same time each year.

SAD has been linked to changes in the brain prompted by shorter daylight hours and less sunlight in winter. As seasons change, people experience a shift in their biological internal clock or circadian rhythm that can cause them to be out of ...

April 30, 2024 - Because SAD that starts in winter is related to the reduced levels of daylight, it's less often found in countries where there's plenty of sunshine year-round. It's not clear what causes SAD that starts in spring or summer. Some believe it's linked to higher levels of light that may disrupt sleep patterns.

Seasonal Affective Disorder is a type of depression that typically occurs during the fall and winter months when there is less natural sunlight. While anyone can experience SAD, it is most common in people who live in regions like New Jersey with long winters and shorter daylight hours.

If your mood relates to a recent event, such as a relationship breakup, then you may well be feeling sadness. But if that breakup was months ago, or you can see no clear reason for your change in mood, you could be depressed, and it might be helpful for you to chat to your GP about what’s causing you to feel the way you do.

Most behavioral health experts agree that SAD is caused by a lack of sunlight during the winter months, when the days are shorter and daylight is scarce.

January 7, 2025 - Seasonal depression, also known as seasonal affective disorder (SAD) or the “winter blues,” is a subtype of depression or bipolar disorder that occurs and ends around the same time every year. Seasonal depression typically occurs when the seasons change and most symptoms begin in the fall ...