Insomnia is a much-dreaded health issue, but emerging research may make the disorder easier to identify, and subsequently treat. As it turns out, insomnia is not a "one-size-fits-all" health issue, so to speak: A new study discovered there are five types of insomnia with their own unique sets of symptoms — and, depending on the type of insomnia, they may even require different medical treatment.

A University of Pennsylvania found that 1 in 4 people in the U.S. will develop insomnia each year. Further, the American Academy of Sleep Medicine reported about 10 percent of people will experience chronic insomnia that interferes with their daily lives. According to the Mayo Clinic, common symptoms of insomnia include difficulties falling asleep and staying asleep, as well as waking up too early in the A.M., and daytime fatigue. Women are also more likely to experience insomnia than men, as are people who are multiply marginalized.

This most recent study was conducted by researchers at the Netherlands Institute for Neuroscience (NIN), and published in The Lancet Psychiatry on Jan. 7. By enlisting the help of thousands of volunteer participants for the study, the scientists were able to discover that insomnia is a more complicated health issue than many people may have thought.

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The researchers at NIN discovered the way this health disorder manifests, and the accompanying symptoms, can vary depending on the type of insomnia. Type 1 is characterized by "neuroticism," and feelings of tension and depression. Both type 2 and type 3, on the other hand, seemed to cause less distress than type 1. In fact, as the researchers revealed in the Jan. 8 press release, types 2 and 3 were "distinguished by their high versus low sensitivity to reward." Type 4 and type 5 experienced even fewer feelings of tension and distress. Stressful life events were found to create "severe and long-lasting insomnia" in people who had type 4, while those with type 5 seemed to be unaffected by it.

The scientists conducted EEGs, a scan the measures brain waves, on study participants, and found those with each type of insomnia responded differently to external stimuli. When the scientists tested the volunteers five years later, after the initial findings, a majority of the volunteers had retained the same type of insomnia —which the researchers said in the press release suggests "anchoring in the brain."

Not only did the researchers identify five unique types of insomnia, but they discovered that the most effective medical treatments differed from type to type. For example, some types seemed more responsive to cognitive behavioral therapy, while others seemed more responsive to sleep medications.

“While we have always considered insomnia to be one disorder, it actually represents five different disorders. Underlying brain mechanisms may be very different," the researchers explained in the Jan. 8 press release.

These new findings could make a huge difference when it comes to further research surrounding insomnia, and the development of potential treatments. Though this breakthrough about insomnia is the first of its kind, physicians and researchers will hopefully continue to gain a better understanding of the types of insomnia. With one in 10 people affected by insomnia, this discovery couldn't have come sooner.