Declining Verbal Scores during Adolescence Predict Future Psychotic Disorder
Teens that show a decline in verbal abilities when compared to their peers may have an increased risk of developing psychotic disorders like schizophrenia later in life, according to a new study.
Previous research has shown that people suffering from psychotic illness show poor cognitive performance during childhood. However, whether poor performance in various tests during teenage years predicts a person's vulnerability to certain psychotic disorders hasn't been known. The present study, conducted by researchers from King's College, London, along with their colleagues from Karolinska Institutet, Sweden, found that falling scores in verbal ability tests can be signs of a future psychotic disorder, especially schizophrenia.
The study included more than 10,000 males who were born in Sweden in 1953, 1967, 1972 and 1977. All the study participants were followed till December 2006. Researchers tested the verbal, spatial and inductive abilities of these people using standardized tests at age 13 and 18.
Study results showed that falling verbal ability scores between ages 13 and 18 were a strong predictor for future diagnosis for psychotic disorder. These people were at higher risk of developing schizophrenia than their peers who hadn't shown a decline in verbal ability.
Researchers caution that the study results in no way indicate that people having declining scores in tests will go on to develop a psychotic disorder, and that these scores can't be used as a test for psychosis.
"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. 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," said Dr James MacCabe, lead author of the study from King's Institute of Psychiatry in a news release.
Study authors further state that teenagers who develop a psychotic disorder don't grow at the same rate as their peers. Also, the study found that the decline in verbal ability scores wasn't associated with age of onset of the disorder and so the decline has more to do with development of the brain during adolescence than with the disorder.
The study is published in the journal JAMA Psychiatry.
According to National Institute of Mental Health, schizophrenia is a chronic, severe and disabling brain disorder that has affected people throughout history. People with this disorder hear voices that others don't hear. They may also believe that others are plotting against them. These people may become agitated and withdraw themselves from the society.
About 1 percent of all Americans have this disorder, NIMH says. People with schizophrenia are usually not violent. The risk of suicide is higher by about 10 percent, especially in young males.