Mobile phones support communication, work, learning and access to care. Problems arise when use repeatedly displaces sleep, movement, responsibilities or relationships, or when a person feels unable to reduce it despite harm. High screen time alone is not a diagnosis.
Sleep
Late-night messages, stimulating content and habitual checking can delay bedtime. Light from screens may also affect circadian timing, but content, timing and lost sleep are important. Notifications can fragment sleep even when a person falls asleep easily.
Mood and attention
Research finds associations between problematic use and anxiety, low mood, reduced concentration or poorer wellbeing, particularly among adolescents. Association does not prove that phones alone cause these problems: distress may also increase online use. Effects differ according to content, purpose, social context and vulnerability.
Signs that use may be a problem
- repeatedly sleeping less because of phone use
- checking during driving or other unsafe situations
- conflict, missed work or school, or withdrawal from offline activities
- feeling distressed when unable to check
- unsuccessful attempts to reduce use despite clear harm
Practical changes
- Set a consistent stopping time before sleep.
- Charge the phone outside the bedroom when practical.
- Disable non-essential notifications.
- Remove the most distracting apps from the home screen.
- Create phone-free meals, conversations and study periods.
- Track whether changes improve sleep or mood rather than aiming for perfection.
Children and adolescents
Guidance should consider age, sleep, activity, education and the quality of content—not only minutes. Caregivers can model boundaries, discuss online experiences and create predictable routines. Sudden withdrawal, bullying, self-harm content or major changes in mood need attention.
When to seek help
Seek professional support when use is linked to persistent insomnia, depression, anxiety, self-harm, unsafe behaviour or major impairment. If someone may harm themselves or cannot remain safe, contact local emergency or crisis services immediately.
This article provides general educational information and does not replace mental-health assessment.
Sources
- WHO Europe: Teens, Screens and Mental Health
- WHO: Physical Activity, Sedentary Behaviour and Sleep in Young Children
- WHO: Smartphones and Mental Health
Last reviewed: 28 August 2026