New study suggests hallucinations, alone, do not predict onset of schizophreniaOctober 09, 2015
CHAPEL HILL, NC - Despite decades of study, schizophrenia has remained stubbornly difficult to diagnose in its earliest stage - between the appearance of symptoms and the development of the disorder. Now, a new analysis led by researchers at the UNC School of Medicine and the Renaissance Computing Institute (RENCI) identified illogical thoughts as most predictive of schizophrenia risk. Surprisingly, perceptual disturbances - the forerunners of hallucinations - are not predictive, even though full-blown hallucinations are common features of schizophrenia. The results were published online today in the journal Schizophrenia Research.
"The earlier people are identified and receive treatment when they develop schizophrenia, the better their prognosis," said Diana Perkins, MD, a clinician and professor of psychiatry at the UNC School of Medicine and one of the study's first authors. "If we can identify people at high risk for psychosis we can then develop interventions to prevent the development of schizophrenia and the functional declines associated with it."
Schizophrenia is a chronic mental illness that affects more than 3 million people in the United States. It typically emerges during late adolescence and early adulthood, and remains a chronic and disabling disorder for most patients. Psychosis, which more than 6 million Americans experience, refers to a group of symptoms, including paranoia, delusions (false beliefs), hallucinations, and disorganization of thought and behavior. Psychosis always occurs in schizophrenia, but can also occur in people with bipolar disorder or other medical conditions.
Early warning signs of schizophrenia include mild psychosis-like symptoms. However, only about 15-20 percent of people who have these mild psychosis-like symptoms actually develop schizophrenia or other disorders with full-blown psychosis. Current diagnostic criteria for attenuated psychosis include having at least one of the following: illogical thoughts, disorganized thoughts, or perceptual disturbances of sufficient frequency and severity to impact function.
To help clinicians know where to draw the line, Perkins and Jeffries examined what symptoms were most predictive of psychosis over a two-year follow-up period in a cohort of 296 individuals at high-risk for psychosis because of experiencing attenuated psychosis symptoms. The analysis revealed that suspiciousness and unusual thought content were the most predictive, and that difficulty with focus or concentration and reduced ideational richness further enhanced psychosis risk prediction.
Identification of the most informative symptoms was performed with "stringent randomization tests," according to the other first author, Clark D. Jeffries, PhD, a scientist at RENCI. That means the same classifier algorithm was applied to the true data as well as 1000 random permutations of the data that mixed patients who did and did not progress to frank psychosis.
Importantly, the investigators validated these findings in a new cohort of 592 people with attenuated psychosis symptoms, confirming the findings. Suspiciousness and unusual thought content include a "feeling of being watched," or "it seeming like others are talking about" the person but knowing that this "can't really be true," or fixating on coincidences that aren't actually connected, or finding "signs" in certain experiences or having a distorted sense of time.
Difficulty with focus and concentration refers to problems with distractibility and short-term memory. Reduced ideational richness typically refers to difficulty following conversations or engaging in abstract thinking.
Somewhat surprisingly, perceptual disturbances - seeing shadows or hearing knocking noises with a sense that these experiences are "not real," - while superficially similar to hallucinations were not predictive of psychosis. Although such symptoms were common in those who developed psychosis, they were equally common in those who did not develop psychosis.
"In terms of assessing psychosis risk, I think this study shows we need to be emphasizing the person's thought process, and appreciate that perceptual disturbances may not be a specific early warning sign," Perkins said. "I think that will affect how we develop our diagnostic system in the future for people who are at high risk for psychosis."
The National Institute of Mental Health funded this research.
Additional study coauthors include Barbara Cornblatt of the Zucker Hillside Hospital; Scott Woods, Tyrone Cannon, and Thomas McGlashan of Yale University; Jean Addington of the University of Calgary; Carrie Bearden at the University of California-Los Angeles; Kristin Cadenhead and Ming Tsuang of the University of California-San Diego; Robert Heinssen of the National Institute of Mental Health; Daniel Mathalon of the University of California-San Francisco, and Larry Seidman of Harvard Medical School.
University of North Carolina Health Care
Related Schizophrenia Current Events and Schizophrenia News Articles
Maternal inflammation boosts serotonin and impairs fetal brain development in mice
Fighting the flu during pregnancy sickens a pregnant woman, but it may also put the fetus at a slightly increased risk for neurodevelopmental disorders like autism later in life.
Imaging study shows promising results for patients with schizophrenia
A team of scientists from across the globe have shown that the brains of patients with schizophrenia have the capacity to reorganize and fight the illness. This is the first time that imaging data has been used to show that our brains may have the ability to reverse the effects of schizophrenia.
The brain clock that keeps memories ticking
Just as members of an orchestra need a conductor to stay on tempo, neurons in the brain need well-timed waves of activity to organize memories across time. In the hippocampus--the brain's memory center--temporal ordering of the neural code is important for building a mental map of where you've been, where you are, and where you are going.
New findings linking abnormalities in circadian rhythms to neurochemical to changes in specific neurotransmitters
Results of the first study of its kind to link abnormalities in circadian rhythms to changes in specific neurotransmitters in people with bipolar disorder will be published this week in the journal Biological Psychiatry.
Difficult decisions involving perception increase activity in brain's insular cortex, study finds
As the difficulty of making a decision based on sensory evidence increases, activity in the brain's insular cortex also increases, according to researchers at Georgia State University.
Multiple personality disorder may be rooted in traumatic experiences
A new King's College London study supports the notion that multiple personality disorder is rooted in traumatic experiences such as neglect or abuse in childhood, rather than being related to suggestibility or proneness to fantasy.
Lipid testing underutilized in adults taking antipsychotic medications
Too few adults taking antipsychotic medications are being screened for abnormalities in lipids, which include cholesterol and triglycerides, new research from the University of Colorado Anschutz Medical Campus finds.
Extreme beliefs often mistaken for insanity, new study finds
In the aftermath of violent acts such as mass shootings, many people assume mental illness is the cause. After studying the 2011 case of Norwegian mass murderer Anders Breivik, University of Missouri School of Medicine researchers are suggesting a new forensic term to classify non-psychotic behavior that leads to criminal acts of violence.
Smoking during pregnancy associated with increased risk of schizophrenia in offspring
A study by researchers at Columbia University's Mailman School of Public Health, Columbia University Medical Center (CUMC), New York State Psychiatric Institute and colleagues in Finland reports an association between smoking during pregnancy and increased risk for schizophrenia in children.
Healthy intestinal flora keeps the mind sharp -- with some help from the immune system
A special kind of immune cell serves as an intermediary between gut bacteria and the brain. Dr. Susanne Wolf of the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC) discovered this in tests on mice and published her findings in the journal Cell Reports.
More Schizophrenia Current Events and Schizophrenia News Articles