Smartphones are in pockets, purses and, for some people, under their pillows at night. Most Americans have a smartphone. About 95 percent of teenagers and people under 50 say they have one. For many people, smartphones are a convenience. But for phone addicts, they can feel like an obsession. There are apps to look at, games to play and websites to browse. One in five U.S. teens, for example, say they use YouTube “almost constantly,” and more than half say it would be difficult to stop using social media. The Debate Over Smartphone Addiction Researchers are studying smartphone usage to determine when a person is addicted and how it can damage their mental health. Scientists don’t agree on how to define smartphone addiction or whether it qualifies as an addiction. But they can agree on one thing — overuse is detrimental to a person’s mental health. Scientists don’t currently agree whether there is enough evidence to support the existence of smartphone addiction. Problematic Smartphone Use Some researchers use the term problematic smartphone use (PSU) to describe excessive use that can lead to dysfunction in a person’s life. Dysfunction might include a sense of withdrawal when the phone can’t be used due to a low battery or a situation in which it must be turned off, such as attending a wedding. PSU could also involve reckless behavior, such as using a smartphone while driving. For phone addicts, dysfunction might mean their smartphone usage interrupts their relationships. For others, regular usage may no longer be satisfying, and they need more phone time to feel fulfilled. PSU is an everyday occurrence for many people. In a 2018 study in Computers in Human Behavior,  more than half of surveyed adults said they knowingly used their smartphone when they should have been doing something else with their time. More than a third said they lost sleep to smartphone use, and 65 percent said they used their smartphone for longer than intended. Generalized Internet Addiction But are these signs of addiction? Again, scientists aren’t in agreement. Without its own definition, smartphone addiction can be categorized under generalized internet addiction (GIA), which was first suggested in the mid-nineties as a type of impulse control disorder. The most recent version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) from 2013 only lists gambling under behavioral addictions. Social media, internet and online gaming are not yet considered diagnosable conditions.  Without a structure to work with, researchers have developed varying scales in which study participants can self-identify as having a smartphone addiction. These scales are still a work in progress, and critics say they need to be better defined. Despite the lack of agreement or ability to formally diagnose, the scientific literature shows that too much screen time can seriously affect mental well-being. Smartphones and Mental Health When people use social media apps, the phone can feel like a conduit for social connection. Anxiety can build when the person sees evidence that others socialize offline without them. People can also develop a compulsion to check social media to maintain social connections and not miss updates or information. Read More: What Is a Social Media Cleanse? Fear of Missing Out In 2004, researchers began using the term Fear of Missing Out (or FoMO) to describe the anxiety that comes from both the sense of exclusion and the need to constantly check social media to maintain bonds. FoMO is emotionally exhausting because the person falls into a constant cycle of checking their phone for updates. People with FoMO have also reported being distracted from notifications that flash on their phones to alert them to new messages, postings or comments. These interruptions from alerts translate into less concentration and productivity at work or school. In addition to the higher levels of anxiety associated with FoMO, studies have found that too much phone time is linked to “significantly increased risks” of poor sleep quality and depression. Read More: What is Anxiety and How Can Worries Overpower Us? Doomscrolling FoMO is also associated with “doomscrolling,” a seeking behavior in which a person intentionally looks at negative headlines, stories, posts or pictures. A person, for example, could doomscroll stories about current events like the pandemic or the invasion of Ukraine. Or they could doomscroll more locally-based content, such as high housing prices in their area. A 2022 study in Applied Research in Quality of Life XYZ found that doomscrolling caused psychological distress and “significantly and negatively” impacted life satisfaction, mental well-being and harmony in life. Although the study participants reported habits such as losing track of time or obsessively refreshing a feed to check for new information, other studies have found a person does not have to spend much time reading bad news to catch a sense of sorrow. A 2021 study in Plos One found negative effects emerged within as little as two minutes of exposure. The same study, however, found that stories that showed people being kind to each other during the pandemic did not bum participants out. The authors concluded that people need to have a better balance in their information-seeking online so that “doomscrolling” is countered by “kindness-scrolling.” Read More: Audiobooks or Reading? To Our Brains, It Doesn’t Matter