Doctors may accurately diagnose schizophrenia while in its earliest phase if they know about the significant and widespread cognitive problems from which its patients often suffer, say scientists.
Publishing a new study conducted by researchers at Harvard Medical School and SUNY Upstate Medical University in Syracuse, New York, the American Psychological Association has revealed that the cognitive problems linked with early-stage schizophrenia make it very hard for people with the disorder to work, study or be social.
The researchers say that understanding the early and central role of cognitive problems may help clinicians to more accurately diagnose incipient schizophrenia by telling it apart from other neuropsychiatric disorders that also have cognitive problems, such as attention-deficit hyperactivity disorder (ADHD).
According to them, it may also allow doctors to provide more appropriate treatment.
They say that combining schizophrenia's cognitive warning signs with family history and signs of worsening daily functioning may also aid early diagnosis, which may in turn make it possible to ease or even prevent these problems.
The researchers examined 47 previously published, peer-reviewed studies of first-episode schizophrenia that involved 43 separate samples comprising 2,204 patients and 2,775 largely age- and gender-matched control participants.
The psychologists sorted the studies' collective findings into10 areas of neurocognition-including general cognitive ability, attention, memory, and various verbal, motor and visuospatial skills.
They observed that in the very first episode of schizophrenia, cognitive problems were already broad and serious. Early impairment approached or matched the severity of problems seen in patients who had been sick for a while.
The researchers also found that people experiencing their first episode of schizophrenia had significantly worse performance on all cognitive measures than healthy controls who were largely matched for gender and age.
They further revealed that patients struggled the most with processing speed and with verbal learning and memory, especially when encoding information. Although many psychiatric and eurological illnesses, such as bipolar disorder, affect processing speed, schizophrenia seems to disrupt it more profoundly.
The study also showed that measured IQ and other cognitive abilities dropped the most between the high-risk period just before symptoms appear and the first acute phases. After that, these cognitive abilities were stable. This cognitive pattern, when combined with other signs such as clinical symptoms and family history, could suggest a diagnosis of schizophrenia.
The first episode of schizophrenia, which is typically in the late teens or early 20s, brings "a sense of tremendous terror, trauma and shock, along with prominent cognitive disorganization, increasingly compelling unusual and/or paranoid thoughts, altered perceptions, and loss of insight," say lead co-authors Dr. Raquelle Mesholam-Gately and Dr. Anthony Giuliano.
The authors say that cognitive testing could also be useful for older children who have a family history of schizophrenia and emerging clinical symptoms.
Doctors viewing cognitive impairments in a vacuum might think of something like ADHD, but the researchers said the new findings play up the importance of family history and better characterization of clinical or behavioural symptoms, especially around the age of peak risk.
The study has been published in the journal Neuropsychology.