Sleeplessness affects people in vastly different ways. For some people, insomnia is linked to endless exposure to blue light, while in others, it indicates a struggle with depression. Because there’s such a wide range of factors that can lead to the same condition, it’s not always easy to identify and address the problems that various sleepless individuals face. That’s why the authors of a recent Lancet Psychiatry paper propose a different way of looking at insomnia: by tracing it back to five personality types.

Netherlands Institute for Neuroscience researcher Tessa Blanken, the lead author of the new paper, argues that using personality traits and life histories (she calls them “non-sleep characteristics”) may be a better way to approach someone’s struggle to sleep than relying on confusing, albeit established, subtypes based on sleep characteristics. Figuring out a better way to identify these people will hopefully make it easier to offer them targeted treatments.

"“The characteristics we focused on have been shown to be rooted in brain function and structure, and therefore are stable over time."

“We thought we might look into different characteristics that inform the context in which insomnia develops and persists,” she tells Inverse. “The characteristics we focused on have been shown to be rooted in brain function and structure, and therefore are stable over time.”

Blanken came to this conclusion after analyzing the life history details and personality traits of 2,224 participants diagnosed with probable insomnia disorder between 2010 and 2016. Her results allowed her to group the individuals into five personality types characterized by similar reasons for sleeplessness — and suggest different ways to treat them.

Type One: Highly Distressed

Blanken describes type one insomniacs as “highly distressed.” They often report having high levels of pre-sleep arousal — meaning that they feel highly active or anxious before bedtime. In general, type one individuals showed a higher prevalence of depression over the course of their lifetimes compared to other subtypes.

“People in this subtype have a high level of distress across most of the domains, they both report strong negative affect, but they also report a lack of positive affect, or a lack of subjective happiness,” Blanken says.

Type Two: Moderately Distressed, Reward Sensitive

Type twos share a lot of similarities with type ones, says Blanken. They also report high levels pre-sleep arousal and negative affect, though they don’t show the same lack of general happiness that type ones do. These people are highly distressed, says Blanken, but still show “intact responses to pleasurable emotions.”

This group also reported higher levels of insomnia due to stress than controls and other subtypes. In the paper, she hypothesizes that people who show these personality traits might be experiencing a type of insomnia called psychophysiological insomnia — in which stress over sleep itself can keep people awake.

Blanken mapped the personality traits of insomniacs and found that they fell into five categories. Here she shows the traits most common in type one (red), type two (green), and type three (dark blue). The Lancet Psychiatry

Type Three: Moderately Distressed, Reward Insensitive

Blanken explains that type three insomniacs were overwhelmingly defined by their low levels of positivity — both in comparison to controls and to types one and two. They’re about as generally distressed about life as type twos but are insensitive to positive feelings. “The third type has a really clear diminished positive affect and a really low subjective happiness,” Blanken adds.

She also found that type threes tended to have far lower levels of current depression compared to type twos, despite their similar levels of general distress.

Type Four: Slightly Distressed, High Reactivity

Unlike types one, two, and three, type fours tends to score lower in terms of general distress, according to Blanken’s analysis. Instead, the chief driver of their sleeplessness was life events, a pattern the team identified by analyzing subjects’ life history data. In these individuals, life events like financial or relationship struggles result in longer and more sustained amounts of insomnia. Those in this category also reported more adverse events during childhood.

Type Five: Slightly Distressed, Low Reactivity

Like type four, Blanken believes that type five insomniacs also develop their insomnia largely due to life events, though they reported fewer adverse events during childhood and less acute responses to life events than type fours. Instead, this group showed low levels of “behavioral activation which Blanken explains is a rough measure of motivation. In both types four and five, she found that people tended to develop their insomnia later in life — specifically above the age of 40.

How Treatment Differs Between Groups

This classification isn’t just another personality test for insomniacs, says Blanken. There are important differences in the way each group responds to common treatments.

Those who experienced type two insomnia, for example, reported that cognitive behavioral therapy (CBT) actually alleviated their symptoms on insomnia. By comparison, the type four insomniacs largely reported no change in their sleep patterns due to CBT. Though she admits that this work is in it’s early stages, she believes that that this might indicate that type fours might benefit from a different type of therapy that addresses their adverse experiences during childhood.

"“This is really only the beginning. Ultimately, I would hope that it would help people by optimizing treatment."

She also showed than bendiazopene, a common drug used to treat insomnia, produced different side effects on some subtypes. It was effective in helping types two and three stay asleep but didn’t have the same effect on type threes. There she found it had a different effect: type three insomniacs reported significantly higher levels of fatigue during the day after taking the drug compared to other groups.

At this point she was only able to demonstrate robust differences in treatment for three out of her five groups, but hopes that by applying this framework she might be able to help people narrow in on what treatments might work best for their own type of insomnia.

“This is really only the beginning. Ultimately, I would hope that it would help people by optimizing treatment,” she says.