Monsoon and Mood Disorders: The Role of Serotonin and Melatonin Dysregulation

Team IIBP Anveshan, Issue 62, Volume 6

Rita always loved the rains—until last year. As June arrived, the city turned lush green, the  skies greyed, and puddles formed little mirrors on the streets. But something inside Rita  dimmed. She started waking up tired, stopped replying to messages, cried without a reason,  and couldn’t find joy in her favorite things. “It’s just the weather,” her family shrugged. But it  was more than that. 

Every monsoon, many like Rita experience an unexplained emotional dip. While the scent of  wet earth evokes nostalgia in some, for others, it triggers sadness, irritability, or even  depression. The culprit? A complex dance between two brain chemicals—serotonin and  melatonin—that go out of rhythm when the skies turn dark. 

Let’s break it down. 

Why Does the Monsoon Affect Our Mood? 

Our brain is like a chemical factory, and two of its most important workers are serotonin— the “happy hormone”—and melatonin, the hormone that regulates our sleep. 

Serotonin boosts mood, appetite, and energy. 

Melatonin controls our sleep-wake cycle and makes us feel drowsy when it’s dark. 

Now here’s the tricky part: both these hormones are influenced by light. When sunlight  hits your eyes, your brain produces more serotonin and suppresses melatonin. But during  monsoon, especially in tropical regions, the sunlight drastically reduces for days or weeks.  The result? Serotonin levels dip, making you feel low, while melatonin levels spike, making  you sluggish and sleepy all the time. 

A 2021 Indian Journal of Psychiatry study found that 1 in 5 people reported mood  disturbances during prolonged rainy seasons. And among those with a predisposition to  depression or anxiety, symptoms tend to worsen. 

Seasonal Affective Disorder (SAD): A Real Diagnosis 

What Rita experienced is not just “rainy day blues.” It closely resembles Seasonal Affective  Disorder (SAD)—a type of depression that occurs in a seasonal pattern. While it’s  commonly associated with winter in Western countries, in tropical climates like India, the  monsoon version is less studied but very real.

The Circadian Rhythm Theory in psychology explains this well. Our internal body clock  (circadian rhythm) is aligned with sunlight. When there is a sudden reduction in light  exposure, this rhythm gets disturbed—messing up our sleep, energy, appetite, and even how  we process emotions. 

What Can You Do About It? 

The good news? You don’t need to wait for the sun to feel better. Here are some practical  and science-backed tips

1. Maximize Light Exposure 

• Open your windows and curtains, even on cloudy days. 

• Use bright white artificial lights indoors, especially in the morning. Light therapy  boxes (10,000 lux) are used in colder countries—consult a professional before use. 

2. Move Your Body 

Exercise increases serotonin. A brisk walk, dancing, or yoga for even 20 minutes a  day helps lift mood. 

3. Maintain a Routine 

• Stick to regular sleep-wake times even if you feel like oversleeping. This stabilizes  melatonin release. 

4. Watch What You Eat 

• Include foods rich in tryptophan (a serotonin precursor)—like bananas, eggs, milk,  and nuts. 

• Stay hydrated and avoid excessive caffeine, which can disrupt sleep further. 5. Stay Connected 

• Talk to a friend. Reach out, even if you don’t feel like it. Isolation amplifies mood  issues. 

• If symptoms persist for more than two weeks, seek professional help. Therapy and  medication can help regulate mood chemicals effectively.

Back to Rita… 

Rita finally visited a psychologist who diagnosed her with seasonal affective symptoms. With  light exposure, daily movement, and mindful therapy, she began to feel better. By the next  monsoon, she was prepared—with fairy lights in her room, a gratitude journal on her desk,  and a yoga mat she didn’t ignore. 

Because sometimes, the clouds outside can sneak into our minds. But with the right tools,  we can find our own sunshine—even in the rain

Reflection Questions: 

• Have you noticed your mood or energy change during monsoon? 

• What daily habits can you adopt to protect your mental well-being during gloomy  seasons? 

• Could someone around you be silently struggling with seasonal mood dips?

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