Teens who experience a decline in verbal skills, compared to their peers of friends, are at increased risk for developing a psychotic disorder in adulthood.
Although research has shown that patients who develop adult psychosis experienced several cognitive deficits during childhood and adolescence, it had remained unclear whether these deficits became more severe during adolescence.
For the study, researchers looked at data from 10,717 males born in Sweden in 1953, 1967, 1972 and 1977, and followed through to December 2006. Verbal, spatial, and inductive ability were tested at ages 13 and 18 using standardized tests.
The findings showed that individuals whose verbal ability declined, compared to their peers or friends between ages 13 and 18, were at greater risk for developing schizophrenia and other psychotic disorders in adulthood.
Decline in verbal score between ages 13 and 18 was a much stronger predictor of later psychosis than the score at age 18 alone.
“We know that the brain undergoes a rapid period of development during adolescence, and these findings add to the evidence that brain development may be impaired in some people, who later develop psychosis,” said James MacCabe, Ph.D., lead researcher of the study from the Department of Psychosis Studies at King’s College London.
“However, it is important to understand that only a small minority of people develop psychosis, so the actual risk of psychosis, even among people with a decline in verbal abilities, remains very low. This could certainly not be used as a ‘test’ for psychosis.”
The researchers note that the drop off in verbal ability is relative to the average population and therefore does not represent an actual deterioration in verbal ability between ages 13 and 18.
In fact, it’s more likely that the individuals who will later develop psychosis do not progress along with their peers.
The authors found that the decline in verbal skills was not linked to the age of onset of psychosis suggesting that the decline most likely represents a neurodevelopmental process specific to the teen years rather than a marker of early stage psychosis.
The study is published in JAMA Psychiatry.
Source: King’s College London