A new study finds that people with psychotic disorders, such as schizophrenia, show reduced cognition in several areas, and these impairments are likely to worsen with age.
The findings, published in JAMA Psychiatry, reveal similar 18-year trajectories of cognitive decline among people with schizophrenia spectrum disorders as well as those with other psychotic conditions, such as psychotic bipolar disorder, major depression with psychosis and substance induced psychosis.
The study also shows that cognitive impairments are associated with the patients’ symptoms, particularly loss of interest in everyday activities.
The research is part of the Suffolk County Mental Health Project, which began in 1989, and whose aim is to find out what challenges patients with psychotic disorders face throughout their lives.
Cognitive impairment is an established core feature of schizophrenia, and it is associated with poor social and employment outcomes for those affected. However, little is known how cognitive impairment may progress in the longer term in schizophrenia and other psychotic disorders, since studies beyond 10 years after first diagnosis are rare.
The new study involved 445 participants who had been admitted to psychiatric inpatient units within Suffolk County, New York. Participants came back to complete cognitive testing at two and 20 year follow-up after their first episode of psychosis.
Participants took a range of tests which measured different aspects of cognitive functioning, including vocabulary knowledge, memorization and the ability to conceptualize across ideas and decision-making.
The participants also completed clinical interviews that assessed their symptom levels and how well they were doing socially, as well as functionally in terms of vocation and employment.
Twenty years after their diagnosis, the patients’ cognitive functioning was compared with a group of non-psychotic participants from Suffolk County matched by gender and age.
“Our study provides the first comprehensive picture of long-term cognitive changes and associated clinical and functional outcomes in psychotic disorders, and is an important step toward providing clarity on what challenges people with these disorders face in the community,” said co-first author Dr. Anne-Kathrin Fett, senior lecturer in psychology at City, University of London.
“However, it is important to note that while there was a general downward trend, participants varied in terms of cognitive changes and some also achieved improvement over the follow-up period.”
“We need to find out what can influence cognitive functioning positively. We do not yet have medication, but lifestyle changes may be able to improve cognition long-term to some extent.”
“Importantly replication and further studies will be necessary to offer directions for the development of strategies to help prevent the progressive deterioration of cognitive functioning in later stages of psychotic illness.”
Source: City, University of London