Your smartphone habit may be doing more than harming your relationships -- it could be damaging your sleep and ultimately triggering depression and anxiety.
A growing body of research finds that smartphone users have sleep problems that interfere with their daily functioning.
"We know that young people and older people are on some kind of screen before bedtime, even within the last 30 or 60 minutes before going to sleep," said Dr. Shalini Paruthi, the director of the Pediatric Sleep and Research Center at Saint Louis University.
"Everybody has a wakeup alarm, but it may be equally important to set a bedtime alarm," Paruthi continued. "That way it gives ourselves a signal: 'Okay, time to put this away. Time to start my bedtime routine.'"
One study, published in 2014, found an association between smartphone use after 9 p.m. and decreased sleep quantity. Its researchers surveyed 82 upper-level managers and found that those who slept less felt depleted in the morning and were less engaged at work the next day.
Strikingly, as part of the study, smartphones were worse for employees' sleep and workplace engagement than other screen-based devices, such as laptops, tablets or television, perhaps in part because they make it hard to detach from workplace obligations.
And another study, also published in 2014, found that university students who self-reported high use (based on a six-point Smartphone Addiction Scale) were also more likely to report higher levels of depression, anxiety and what's know as "daytime dysfunction," or excessive daytime sleepiness.
While the study didn't prove that smartphones cause anxiety and depression, it did show a correlation between high smartphone use, high depression levels and poor sleep. In the study, respondents who reported suffering from depression and anxiety were also more likely to report poor sleep quality.
Sleep loss and anxiety are unfortunate bedfellows. Lack of sleep can provoke parts of the brain that regulate anxiety, and unfortunately, innate worriers are most susceptible to the damaging effects of sleep loss.
There's some evidence, as HuffPost reported in February, that some people may find smartphone behavior changes more challenging than others: In a 2015 study published in Personality and Individual Differences, respondents who checked their smartphones frequently were more prone to impulsive, moody, temperamental and materialistic behavior.
Regardless of personality type, it's clear that sleep needs to be a top priority for all of us. "Smartphone use, tablets, screen time use -- it can have such a major effect on sleep," Paruthi said. "We don’t want screens to cut into the quantity of our sleep -- but also the quality of our sleep."