It's hard to escape screens; there is a roughly 100 percent chance you are looking at one right now. And though the long-term effects of screen time are still being studied, the effects of excessive internet and smartphone use are well-documented. "Pathological" internet use has been linked to depression in teens, and it may even shrink gray matter.

Now, a small new study suggests that for teens, being hooked on the internet and smartphones may harm brain chemistry, as well.

The research was presented yesterday (Nov. 30) at the Radiological Society of North America's annual meeting in Chicago.The paper, which was presented by lead study author Dr. Hyung Suk Seo, a professor of neuroradiology at Korea University in Seoul, South Korea, found an imbalance of chemicals in the brain of "internet-addicted" teenagers. This imbalance was similar to that seen in people experiencing anxiety and depression. [9 Odd Ways Your Tech Devices May Injure You]

But there's also good news: The imbalance is reversible in several weeks using a type of psychotherapy called cognitive behavioral therapy.

A chemical imbalance

In the study, researchers examined the brains of 19 internet- and smartphone-addicted teenagers and 19 nonaddicted teenagers using magnetic resonance spectroscopy, a form of MRI that can reveal changes in the chemical composition of the brain. (Internet and smartphone addiction were measured using standardized questionnaires.)

Compared with the control group, the teens with internet and smartphone addiction showed a clear overabundance of a neurotransmitter called gamma-aminobutyric acid (GABA) in one region of the limbic system, the brain's emotional control center. GABA is an inhibitory neurotransmitter, meaning that it blocks nerve cells from firing.

GABA is found in everyone's brain, but too much of this neurotransmitter in the wrong areas can have stultifying effects."When the normal function of the limbic system is disturbed, patients can develop anxiety, depression or addiction," said Dr. Max Wintermark, a professor of radiology and the chief of neuroradiology at Stanford University. Wintermark was not involved with the new research but said that he was intrigued by it because of the increasing prevalence of phones and web devices in society.

"There have been multiple studies published [that link] addiction to alcohol and other substances with chemical imbalances in different regions of the brain, but this is the first study I've read about internet addiction" that shows such a link, Wintermark told Live Science.

Measuring addiction

For most people, checking email first thing in the morning or spending an hour scrolling though Instagram after work does not signify an internet addiction.

Rather, internet addiction, as defined by the American Psychiatric Association, is an excessive use of the internet that leads to impairment of everyday life, sleep and relationships. Studies from around the world have found that the rates of internet addiction in young people range from less than 1 percent to 18 percent.

The teens who participated in Seo's study all took standardized tests used to diagnose internet and smartphone addiction. The participants whose scores indicated an addiction tended to saythat their internet and smartphone use interfered with their daily routines, social lives, sleep and productivity. These teenagers also had significantly higher scores in depression, anxiety, insomnia and impulsivity than the control group (the participants whose scores did not indicate internet addiction).

Due to the small sample size used in the study, Wintermark stressed that it's too early to say that the chemical imbalances observed in the teens' brains are linked to clinical problems such as anxiety and depression. Further testing on a larger group of people is needed, he said.

Wintermark noted that 12 teens in the study with addiction went on to participate in cognitive behavioral therapy, and after nine weeks, they all showed decreased or normalized levels of GABA in their brains. According to the researchers, those teens completed a modified form of therapy that's used to treat video game addiction, involving weekly 75-minute sessions of mindfulness exercises. These include recognizing internet impulses, finding alternative activities and expressing emotions.

"With appropriate intervention, the teens were able to basically correct those chemical changes" in their brains, Wintermark said. "That's the part of the study I find most interesting. It shows there's hope."

The study has not yet been published in a peer-reviewed journal.

Originally published on Live Science.