Modest declines in cognition were observed among patients with psychotic disorders in the 20 years after their first hospitalization, according to a longitudinal study.
Cognitive domains were measured through 11 tests with a variety of scoring ranges. The Verbal Paired Associates test (VPA II), for example, was one of two tests used to evaluate verbal declarative memory and ranged in score from 0-8. The Trail Making Test-A (TMT-A) was one of three tests used to measure abstraction-executive function and ranged from 24-180.
In 445 individuals with psychotic disorders, four cognitive domains — visual declarative memory, verbal declarative memory, attention and processing speed, and abstraction-executive function — declined from two years after the cohort’s first psychiatric hospitalization to 20 years after (average decline = -0.31, P<0.001), reported Roman Kotov, PhD, of Stony Brook University in New York, and colleagues.
At 20 years, verbal fluency did not change and verbal knowledge significantly increased (decline = 0.34), they wrote in JAMA Psychiatry.
“This is sort of an alert that it is important to keep an eye on cognitive function,” Kotov told MedPage Today, adding that performing neuropsychological evaluations in this population every five years is “a good idea.”
The cognitive decline observed in this study may be secondary to other factors like a lack of social or physical activity, both of which have been shown to have modest neuroprotective effects, Kotov hypothesized. It may also be caused by deficits that are intrinsic to psychotic disorders themselves, he added.
Perhaps the strongest hypothesis is that certain medical conditions that disproportionately affect people with psychotic disorders, like hypertension and diabetes, for example, may be affecting the brain and cognition, Kotov said.
This study involved a cohort of adults with schizophrenia (211), affective psychoses (164), and other psychoses (70) who had IQs higher than 70 from 12 inpatient facilities in Suffolk County, New York. At 20 years, a control group of 260 individuals was recruited from the same zip codes in which the psychosis cohort resided.
Overall, the cohort — a mean age of 50 at 20-year follow-up — was majority male and mostly white, with more than half of participants not completing a high school education.
Individuals with schizophrenia had more severe cognitive impairment than all other groups in the study, although the change over time was similar compared to the other groups, the authors reported.
The cognitive declines observed were associated with loss of employment (P<0.009) and worsening negative symptoms such as blunting of affect or anhedonia (P<0.009), the authors reported.
In contrast, reality distortion symptoms and social functioning were not associated with cognition for the most part, they added.
“This is consistent with cross-sectional findings linking cognitive impairment to vocational rather than social outcomes and to negative rather than positive symptoms,” the authors noted. “Correlated change may point to bidirectionality (i.e., the factors influence each other) or to the influence of a third underlying variable.”
Individuals with psychotic disorders had significant cognitive decline in verbal knowledge, fluency, and abstraction-executive function compared to the control group of individuals recruited from the same zip codes (P<0.05), and these deficits peaked among participants who were 50 years and over, they added.
“In the general population, vocabulary and verbal fluency tend to improve with age, and age gradients on these tests might indicate that psychotic disorders interfere with new learning, leading to smaller than expected improvement,” they wrote.
One limitation of the study is that the control group was only recruited at the 20-year point, and prior cognitive changes in this study were compared to other cognitive changes measured in the general population in prior research, which are “imperfect benchmarks,” the authors noted. They also used unadjusted scores of cognitive functioning, they added. Attrition may have affected the findings as well, they noted.
Last Updated December 11, 2019
Disclaimer
Kotov reported receiving grants from the National Institute of Mental Health.
Co-authors reported support from or personal relationships with the American Psychiatric Association, Thomas Jefferson University, the Brain and Behavior Research Foundation, Lundbeck, and Pfizer.
Source: MedicalNewsToday.com
