Sleep loss and chronic sleep deprivation is a problem for many kids and teens. Staying up late and waking up early for work or school has become a way of life, especially with the increasing use of phones and tablets late into the night.
Researchers worry, however, that this social jet lag may result in serious health and mental health risks. A new study suggests that for teenagers, even a short period of sleep restriction could, over the long term, raise their risk for depression and addiction.
University of Pittsburgh investigators invited 35 participants, aged 11.5-15 years, into a sleep lab for two nights. Half the participants slept for 10 hours, while the other half slept only four hours. A week later, they came back to the lab for another two nights and adopted the opposite sleep schedule from their initial visit.
Each time they visited the lab, the participants underwent brain scans while playing a game that involved receiving monetary rewards of $10 and one dollar. At the end of each visit, the teens answered questions that measured their emotional functioning, as well as depression symptoms.
Results from the brain imaging showed that sleep deprivation affected the putamen, an area of the brain that plays a role in goal-based movements and learning from rewards.
When participants were sleep-deprived and the reward in the game they played was larger, the putamen was less responsive. In the rested condition, the brain region didn’t show any difference between high- and low-reward conditions.
Lead researchers Drs. Peter Franzen and Erika Forbes also found connections between sleep restriction and mood. Specifically the found that after a night of restricted sleep, the participants who experienced less activation in the putamen also reported more symptoms of depression.
This is consistent with findings from a large literature of studies on depression and reward circuitry that suggest depression is characterized by less activity in the brain’s reward system.
Researchers believe that sleep deprivation in the tween and teen years may interfere with how the brain processes rewards. Difficulty in reward-processing could then disrupt mood and put a person at risk of depression, as well as risk-taking behavior and addiction.