Smartphone Ownership at 12 Linked to Eating Disorder Symptoms by 14, Study Finds

Researchers are examining whether the timing of smartphone ownership may be associated with eating-disorder symptoms during early adolescence.

Children who own a smartphone at age 12 may be more likely to report symptoms associated with eating disorders two years later, according to a new study of nearly 9,000 US adolescents.

The research, published September 25 in JAMA Network Open, examined whether the age at which young people begin owning smartphones is associated with eating-disorder symptoms during early adolescence. Researchers analyzed data from the long-running Adolescent Brain Cognitive Development (ABCD) Study.

The study found that smartphone ownership at age 12 was associated with a higher likelihood of several eating-disorder symptoms at age 14, including binge-eating symptoms, inappropriate behaviors intended to prevent weight gain, and tying self-worth to weight.

The researchers emphasized that the findings show an association, not proof that owning a smartphone directly causes eating disorders.

What the Study Found

The researchers analyzed data from 8,957 adolescents in the United States.

Among them, 6,225, or 69.5%, owned a smartphone at age 12. The study followed participants over time and assessed several eating-disorder symptoms at ages 12 and 14.

At age 14, smartphone ownership at 12 was associated with:

• 67% higher risk of binge-eating symptoms

• 50% higher risk of inappropriate compensatory behaviors to prevent weight gain

• More than twice the risk of tying self-worth to weight

• 49% higher risk of reporting any measured eating-disorder symptom

These figures come from the study's adjusted longitudinal analyses.

The researchers also found associations between smartphone ownership and some eating-disorder symptoms at age 12, including binge eating and linking self-worth to weight.

Smartphone Ownership Was the Focus — Not Screen Time

Much previous research has focused on how much time children spend on screens or social media.

Jason Nagata, MD, MSc, a professor of pediatrics at the University of California, San Francisco and the study's lead author, wanted to examine a different question: whether the age at which children own a smartphone might be associated with later eating-disorder symptoms.

The study therefore compared adolescents who owned smartphones at age 12 with those who did not, while adjusting for a range of demographic, behavioral and health-related factors.

The researchers also accounted for ownership of other devices, including tablets, laptops and smartwatches.

Why Age 12 May Matter

Early adolescence is a period of major physical, emotional and social change.

Puberty can increase awareness of body shape and appearance, while young people are also becoming more sensitive to peer opinions and social evaluation.

Nagata suggested that smartphones may give children easier access to appearance-focused content, including social media posts featuring edited or carefully curated images.

The study itself discusses several possible pathways that could help explain the observed association, including social media exposure, body-image pressures and disrupted sleep. However, the researchers say future research is needed to determine which mechanisms may be responsible.

Smartphone Owners Reported More Weight-Related Concerns

The differences were not limited to binge eating.

In the study, adolescents who owned smartphones at age 12 were more likely to report that their self-worth was tied to their weight.

The longitudinal analysis found a risk ratio of 2.03 for this symptom at age 14 among those who owned a smartphone at 12.

The study also found a 50% higher risk of inappropriate compensatory behaviors intended to prevent weight gain.

These behaviors can include actions such as excessive exercise or restricting food intake, although the study measured specific symptoms rather than diagnosing participants with a full eating disorder.

That distinction matters.

The Study Did Not Diagnose Every Participant With an Eating Disorder

Eating-disorder symptoms exist on a spectrum.

Some adolescents may experience individual symptoms without meeting the clinical criteria for a diagnosed eating disorder.

The researchers deliberately examined symptoms such as binge eating, compensatory behaviors, worry about weight gain and self-worth tied to weight. This allowed the study to capture disordered eating behaviors that may fall below the threshold of a formal diagnosis.

As a result, the study should not be interpreted as showing that 24.2% of smartphone-owning adolescents developed an eating disorder.

Instead, the study reported that nearly one-quarter of smartphone owners in its sample reported at least one measured eating-disorder symptom at age 14.

Why Social Media May Be Part of the Explanation

One possible explanation is exposure to appearance-focused content.

Social media platforms can expose young people to influencers, peers and other users whose images may be edited, filtered or carefully selected.

Nagata said that comparing oneself with curated online images could contribute to body dissatisfaction and lower self-esteem, which are relevant risk factors for eating disorders.

However, smartphone ownership itself does not prove that social media caused the symptoms observed in the study.

A smartphone can be used for many purposes, including communication, schoolwork, entertainment and non-social applications. The study did not establish a single mechanism explaining the associations.

Experts Say Parents Can Use Guardrails

Mitch Prinstein, a psychology and neuroscience professor at the University of North Carolina at Chapel Hill who was not involved in the study, said delaying smartphone access may benefit some children.

Rather than giving young adolescents unrestricted access, he recommended gradually increasing exposure to social media and other online activities.

The study authors similarly point to the importance of parental involvement.

Parents who give preteens smartphones may consider setting limits on which applications can be installed, restricting access at certain times and keeping phones out of bedrooms.

Nagata also recommends having open conversations with children about what they encounter online and watching for changes in eating behavior or the way they talk about their bodies.

There Is No Single “Right” Age for a Smartphone

The researchers do not claim that the study identifies a specific age at which every child should receive a smartphone.

Nagata said the findings do not provide a “magic answer” for when children should get their first smartphone.

Instead, the results suggest that the timing of smartphone ownership may be one factor worth considering when parents think about children's digital access and mental health.

The study's authors also call for more research into the mechanisms behind the association and whether changes in smartphone ownership correspond with changes in eating-disorder symptoms over time.

Social Media Access Is Already Common Among Younger Children

The source article notes that many major social media platforms set 13 as the minimum age for creating an account.

Yet previous research from Nagata's laboratory has found that a substantial proportion of 11- and 12-year-olds report having accounts on platforms such as TikTok and Instagram.

That gap between platform age requirements and actual use is part of the broader challenge facing parents.

A smartphone can provide access to social platforms even when children are below the stated minimum age for creating an account.

What Parents Can Do

The findings do not mean parents need to assume that giving a child a smartphone will lead to an eating disorder.

Instead, the study supports a more cautious approach to early smartphone access.

Parents may consider:

• Setting clear rules for smartphone use.

• Limiting access to social media and other potentially harmful content.

• Using parental controls and age-appropriate app restrictions.

• Keeping smartphones out of children's bedrooms at night.

• Discussing appearance, body image and online content openly.

• Paying attention to changes in eating habits or attitudes toward weight.

• Encouraging children to talk about upsetting or confusing content they encounter online.

These steps are not presented by the study as a guaranteed way to prevent eating disorders. They are practical ways to maintain parental involvement as children gain greater independence online.

What the Study Cannot Tell Us

The study has several important limitations.

Most importantly, it is an observational cohort study. Even though researchers examined participants over time and adjusted for multiple potential confounding factors, the design cannot establish that smartphone ownership itself caused the later symptoms.

Children who receive smartphones at age 12 may differ from those who do not in ways that are difficult to completely account for.

The researchers therefore concluded that smartphone ownership was associated with eating-disorder symptoms and called for future research to identify the mechanisms behind those associations.

The study also examined smartphone ownership rather than measuring every aspect of how individual adolescents used their devices.

That distinction is important because two children can own smartphones while having completely different patterns of screen time, social media use, parental supervision and online experiences.

The Bottom Line

A large US cohort study found that owning a smartphone at age 12 was associated with a higher likelihood of several eating-disorder symptoms at age 14.

The strongest longitudinal associations involved binge-eating symptoms, compensatory behaviors, and tying self-worth to weight.

The findings do not prove that smartphones cause eating disorders. Instead, they add to growing research examining how early digital access may interact with body image, social media exposure, sleep and adolescent mental health.

For parents, the message is less about finding a universally correct age for a first smartphone and more about considering how early access is introduced, what children can access, and how closely adults remain involved in their digital lives.

Frequently Asked Questions

Does owning a smartphone at age 12 cause eating disorders?

No. The study found an association between smartphone ownership at 12 and later eating-disorder symptoms. It did not establish a direct cause-and-effect relationship.

How many adolescents were included in the study?

The analysis included 8,957 US adolescents, of whom 6,225 owned a smartphone at age 12.

What happened to smartphone owners by age 14?

Smartphone ownership at age 12 was associated with higher risks of binge-eating symptoms, inappropriate compensatory behaviors, self-worth tied to weight and reporting any measured eating-disorder symptom at age 14.

Did the researchers study social media use?

The study's main exposure was smartphone ownership at age 12, rather than a simple measure of social media use. The authors discuss social media exposure as one possible mechanism that may help explain the observed associations.

Should parents avoid giving 12-year-olds smartphones?

The study does not establish a universal rule for the appropriate age. It suggests that the timing of smartphone ownership may be relevant and supports further research into early smartphone access and adolescent health.

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