ADHD and Seasonal Change: Why Symptoms Shift With the Sun
The influence of sunlight, Vitamin D, and seasons on ADHD.
Updated May 26, 2026 | Reviewed by Kaja Perina
ADHD is a neurodevelopmental condition that affects attention , emotional regulation , and energy. Unbeknownst to many people, the nature and intensity of symptoms can change over time. They actually evolve with seasons. Now that summer is close, many people with ADHD may notice that the winter funk is slowly leaving. Energy may feel higher, distraction becomes easier to manage, but sleep may become more elusive. It's not just an impression, but something that seems to affect all people with ADHD.
Studies show that in summer, people are more energized and chipper, while in winter, ADHD symptoms often become harder to manage, and people feel blue and more nervous. While seasonality affects all individuals, it appears that people with ADHD are disproportionately affected by it, with a much higher likelihood of having Seasonal Affective Disorder (SAD) in winter, and more sleep issues during summer.
How Seasonality Affects ADHD Diagnosis
This effect goes as far as affecting how likely you are to get an ADHD diagnosis: A Dutch study of more than 5000 people found that people were more likely to be diagnosed with ADHD in early spring, when inattentive and hyperactive symptoms peaked, than in autumn, right after summer. The reason is that ADHD symptoms become much harder to manage during the winter months.
Another study on 117 people with ADHD confirmed this and found that inattentive symptoms in particular decreased proportionally with sunlight exposure. In summer, people showed less intense ADHD symptoms; in winter, they flared up, with a peak around February and March. The likely reason is the correlation between ADHD and vitamin D levels.
The Role of Vitamin D in Symptom Management
A recent review highlighted that individuals with ADHD tend to have naturally lower levels of vitamin D than the general population, and that supplementation of vitamin D decreases the intensity of ADHD symptoms. One natural way of acquiring Vitamin D is none other than sun exposure, and that is bound to affect ADHD, too.
In winter, the days are shorter, often cloudy, and the sunlight is insufficient to properly let the body produce vitamin D. This leads to a natural deficit in individuals with ADHD, who may start feeling more inattentive, less energized, and may even develop Seasonal Affective Disorder (SAD). The prevalence of SAD is higher in people with ADHD.
Alternatively, in summer, days get longer, people wear clothes with short sleeves, and are more exposed to sunlight. With Vitamin D levels replenished, this may lead to an increase in energy, as well as a natural reduction in ADHD symptom intensity.
This can also affect how you react to your medication . Personally, I know I have to lower my ADHD medication dosage around May, or I get more anxious , and increase it again around November, or it simply doesn't work as much.
How to Manage ADHD with Seasonality In Mind
First, being aware that seasons can affect your ADHD symptoms can help. It can help you plan ahead, keep the big projects for summer, while you take it easier and focus on outlines during winter. You can have a chat with your medical provider if you notice that your medication does not function in the same way during winter and during summer. In other words, just the awareness already helps plenty with the management of symptoms, and of life in general.
Secondly, knowing about the seasonality of ADHD can improve treatment plans, and lead to tailored interventions. It may be useful, for example, to take vitamin D supplements during the winter months to counter the natural dip in mood and energy. Recent studies show that Bright-Light Therapy may be a useful intervention for people with ADHD, effective in reducing Seasonal Depressive symptoms, and improving sleep quality.
On the other hand, sleep disorders tend to increase during summer, on the one hand due to the heat, but also because of the increased light exposure, which can further delay melatonin release in your system. Thus, taking melatonin during summer months when you might struggle the most with sleep can help maintain a healthy sleep rhythm.
As a personal note, I have noticed that my ADHD symptoms improved when I moved from a northern country to a sunnier one. If you are planning any major life changes, it may be worth considering a sunny place as your next destination. It might turn out that, after all, going to the beach is an effective complementary treatment for ADHD. But if you don't have access to the beach, just standing in the sun for roughly 20 minutes a day is a good start.
Kitaneh R, Jalilian-Khave L, Ysrayl BB, Borelli A, Funaro MC, Potenza MN, Angarita GA. The Relationship Between Vitamin D and the Development and Treatment of Attention-Deficit Hyperactivity Disorder: An Overview of Systematic Reviews. Curr Behav Neurosci Rep. 2024 Sep;11(3):164-181. doi: 10.1007/s40473-024-00278-7. Epub 2024 Jun 10. PMID: 40822905; PMCID: PMC12356127.
Fargason RE, Fobian AD, Hablitz LM, Paul JR, White BA, Cropsey KL, Gamble KL. Correcting delayed circadian phase with bright light therapy predicts improvement in ADHD symptoms: A pilot study. J Psychiatr Res. 2017 Aug;91:105-110. doi: 10.1016/j.jpsychires.2017.03.004. Epub 2017 Mar 6. PMID: 28327443; PMCID: PMC7959333.
Luu B, Fabiano N. ADHD as a circadian rhythm disorder: evidence and implications for chronotherapy. Front Psychiatry. 2025 Dec 10;16:1697900. doi: 10.3389/fpsyt.2025.1697900. PMID: 41450833; PMCID: PMC12728042.
Share this post Facebook Bluesky Linkedin Email
There was a problem adding your email address. Please try again.
By submitting your information you agree to the Psychology Today Terms & Conditions and Privacy Policy
Ludovico Saint Amour di Chanaz, Ph.D., is a neuroscientist, neurodiversity advocate, and author of The ADHD User’s Manual.
Get the help you need from a therapist near you–a FREE service from Psychology Today.
This article is part of the Bringwise Psychology Journal — daily insights on human behavior, mental health, and personal growth.