Schizophrenia strikes hard, vicious, and late. A person with the disorder can get all the way through childhood and their teen years without any hallucinations or major disconnects from reality. Then, right on the cusp of adulthood, symptoms of the severe mental disorder can emerge with powerful debilitating effects. Until now, doctors have had no useful, consistent way to see it coming.

But that could change, according to a massive JAMA Psychiatry study published on Wednesday. The research details the first major results from a new branch of personality research that might lead scientists to catch schizophrenia and other severe mental illnesses early –- and perhaps even treat them before they emerge.

The researchers, led by University College London psychiatrist Joseph F. Hayes, Ph.D., found a significant link between a range of teenage personality traits and schizophrenia, schizoaffective disorder (an illness that includes symptoms of schizophrenia and certain mood disorders), bipolar disorder, and a group of other illnesses lumped together as “nonaffective psychotic illnesses” (meaning they include psychotic symptoms but not mood disorders).

They sourced their data, which encompassed 1,017,691 men aged 18 or 19, from the Swedish public domain’s health and personality records on army conscripts from 1974 and 1997. Combined with the future records on hospitalizations for mental illness (also publicly available), they were able to build a detailed map linking personality traits to mental health outcomes.

The Royal Guard, members of the Swedish Armed Forces, march outside The Stockholm Royal Palace in 2015.

The most predictive of the teenage personality traits they investigated were “low social maturity,” “mental energy,” and “emotional stability.” While these terms may sound a bit fuzzy and unscientific, rigorous methods for evaluating behavior led the researchers to define them as such:

  • Mental energy” is, basically, your ability to pay attention to the world around you, focus attention on a task, and react quickly to events.
  • “Social maturity” measures your ability to adjust your behavior, when needed, to match the norms and expectations of people around you.
  • Emotional stability” refers to your ability to deal with emotions in a healthy way, in proportion to the events that spark them. A more emotionally stable person, for example, might read about a stressful news event, feel worried about it, but be able to carry on with their day. A less emotionally stable person might encounter the same event and get derailed, unable to put aside their worry to tackle tasks at hand.

In the study, these three traits turned out to be significant risk factors for developing schizophrenia, schizoaffective disorder, or other nonaffective psychotic illnesses. The relationship between bipolar disorder and personality is more complicated as both low and high social maturity turned out to be risk factors for the illness. For all of these correlations, one major caveat applies: These relationships don’t mean all teens with those traits will get sick. The vast majority won’t. But the data suggest that many of the people who eventually do get sick will come from that pool.

People who can balance their thoughts despite external stresses seem more protected from certain severe mental illnesses

The big honking disclaimer for this study and for any personality research is that the people who write the tests for these traits are experts, working to develop rigorous, useful systems. But they’re also human beings, with their own biases. You’ll find tests for social maturity, for example, that include “patriotism” as key measures. A good way to think about tests for these traits is that they have a lot of potential to be scientifically useful but also pose significant risks for problems.

In this case, the researchers suggest that mental energy, social maturity, and emotional stability that people display as teens are more than just useful predictors of mental illness. They might have a role in causing mental illness to emerge in the brain. If that’s true, therapies designed to help teenagers with those traits control them might actually reduce the number of cases of severe mental illness that emerge. That will certainly be a fascinating subject for future study.

Photos via Getty Images / Ragnar Singsaas, Pixabay, Flickr / Helga Weber