Screentime, Sleep, and Mood: What's The Real Cost?

by: Senna Wardell

The end of the marking period is coming up, and if you’re like most high schoolers, your schedule is already packed with homework, sports, clubs, and maybe even a job. Add in TikTok scrolls, late-night gaming, or catching up on group chats, and suddenly you’re getting way less sleep than you thought. But here’s the catch: too much screen time, especially before bed, doesn’t just make you tired. It can mess with your mood, focus, and even your mental health.

The Science Behind It

A new study shows that excessive screen time is linked to higher risks of depression, anxiety, and ADHD symptoms in teens, while regular sleep and physical activity can help buffer those effects. That means the hours you spend glued to your phone or laptop really do affect how you feel day to day.

Screens mess with your sleep because the blue light signals to your brain that it’s still daytime. Your body then produces less melatonin, the hormone that helps you fall asleep. According to the CDC, teens need 8–10 hours of sleep every night, but most get far less. Lack of sleep makes it harder to concentrate, lowers your energy, and increases stress, basically the opposite of what you need during the school year

Why Mood and Sleep Are Connected

When you’re sleep-deprived, your brain struggles to regulate emotions. That’s why everything feels harder: small problems seem like huge ones, and it’s easier to feel irritable, anxious, or down. In fact, the National Institutes of Health reports that poor sleep is directly linked to worsening depression in teens.

The cycle looks like this:

• More screen time =  less sleep = worse mood = more scrolling to cope.
  Breaking this cycle can make a huge difference in how you feel.

What You Can Do:

Here are some quick tips to manage screen time and improve your mood this school year:

1. Set a bedtime for your phone. Try putting it away at least 30–60 minutes before you sleep.

2. Create a calm nighttime routine. Replace scrolling with reading, journaling, or listening to music.

3. Use “Do Not Disturb.” Late-night notifications make it harder to unplug.

4. Balance with movement. Even short bursts of exercise help counteract the effects of sitting on screens all day. (Harvard Health)

5. Check in with yourself. If you notice your mood dipping, track your sleep and screen habits; you might find a clear connection.

The Bottom Line:

Screens aren’t “bad” in themselves; they connect us, entertain us, and even help with school. But when screen time starts cutting into sleep, your mood and mental health take the hit. By making small adjustments to your routine, you can conserve your energy, enhance focus, and feel more energized throughout the day.