Two new studies show associations between screen time and behavioral and psychological risks for children, adding to a growing body of evidence that excessive use of smartphones and other devices can be deleterious to their health. 

In one study, researchers reported a link between screen time and higher rates of obsessive-compulsive disorder diagnoses among preteens. In the other, the results suggested that using electronic devices to calm youngsters when they’re upset may inhibit their ability to learn to soothe themselves, leading to more frequent, intense emotional outbursts. 

The studies, published in separate journals on Monday, followed their young participants to observe the effects of screen time over months or years.

The study on OCD was published in the Journal of Adolescent Health and tracked more than 9,200 children for two years, starting at ages 9 to 10. Researchers logged how much time the kids spent on devices and found that 4.4% qualified for a new OCD diagnosis.