Scientists have identified a worrisome new form of insomnia: sleeplessness linked to smartphone overexposure.

According to a study published in PLoS ONE, the blue light from a smartphone screen can over-stimulate the brain and interfere with sleep quantity and quality. The researchers used a special phone app to log the number of hours a group of 650 participants spent staring at their smartphone screens and tracked their sleep at night.

They found that participants used their smartphones an average of 38 hours over the month-long study period, and that the more screen time they had, the poorer and shorter their sleep. The effect was particularly noticeable when participants used their smartphones near bedtime.  Researchers concluded that reducing screen time, especially before going to bed, can improve sleep duration and quality.

This article originally appeared in Mind, Mood & Memory, a publication of the Department of Psychiatry at Massachusetts General Hospital dedicated to maintaining mental fitness from middle age and beyond.

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