Researchers in Japan found that severe internet addiction symptoms were associated with lower long term levels of cortisol. The body produces cortisol as its primary stress hormone.
Hideki Tsumura of Tokushima University and Shuhei Izawa of the National Institute of Occupational Safety and Health led the study. The journal, Psychoneuroendocrinology, published the findings.
How Researchers Studied Internet Addiction
The researchers wanted a more stable way to measure stress in people with internet addiction. Saliva and blood tests capture a single moment, and cortisol levels can change with the time of day or recent exercise as well as anxiety before testing.
Hair offers a longer view. It grows about one centimeter each month, so a three centimeter sample taken near the scalp can record roughly three months of hormone production.
The team recruited 155 Japanese university students. The group included 94 women and 61 men with an average age of about 21.
Participants completed the Internet Addiction Test which measures how often internet use disrupts sleep and schoolwork as well as social life. They also completed a depression screening.
Researchers excluded participants with endocrine disorders or medications that affect hormones. The analysis also accounted for age and sex as well as body mass index and depression scores.
Researchers considered hair care habits such as bleaching and washing frequency too.
Hair Samples Showed Lower Cortisol
The researchers found that higher internet addiction scores were associated with lower hair cortisol levels. Participants with high levels of internet addiction symptoms also had lower average cortisol than participants in the low risk group.
The researchers did not find the same pattern with testosterone. Internet addiction symptoms had no clear association with hair testosterone levels and the cortisol finding appeared in both men and women.
Why Low Cortisol Can Reflect Chronic Stress
Low levels of a stress hormone may seem surprising in people who report high psychological distress.
Chronic stress can initially increase cortisol production. Over time, the stress response may become less active, and baseline cortisol levels may fall.
The Study Has Important Limits
The study does not prove that internet addiction causes changes in the stress system. Researchers collected data at one point in time so they could not determine whether lower cortisol contributes to internet addiction or whether compulsive internet use affects the stress response.
The participants were also young university students. The findings may not apply to older adults or people receiving clinical treatment.
Other factors could have affected the results too, such as past trauma and other unmeasured experiences that may influence cortisol levels.
What the Findings Mean for Treatment
Behavioral addictions can become serious and people can treat them. This study adds biological evidence that compulsive internet use may involve measurable changes in the body’s stress system.
If your internet use interferes with daily life then treatment can address both the behavior and the issues that may fuel it. Therapy can also address stress and anxiety as well as depression when those conditions occur alongside compulsive internet use.
Finding Treatment for Internet Addiction
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