T51. VERBAL MEMORY TRAJECTORIES IN CHRONIC INDIVIDUALS WITH SCHIZOPHRENIA ALONG 6 YEARS
Authors: Martins Dayane , de Oliveira Lapa Clara , Hasse-Sousa Mathias , Julia Britto Maria , Reckziegel Ramiro , Bosini Remus Isadora , Czepielewski Letícia , Severino Gama Clarissa 
Published: May 2020

Background

Individuals with schizophrenia (SZ) present different positive, negative and cognitive symptoms that impact psychosocial functioning. Cognitive impairments are shown to be present even in premorbid stages of psychosis, which is related to the neurodevelopmental model of SZ. However, although well described in the literature, the trajectories and mechanisms of cognitive symptoms are still unclear. Some evidence suggest that the deficits may remain stable after the first episode and follow the normal course of aging. Conversely, other studies show a decline in cognitive performance related to the chronicity of the disorder. A central domain widely studied in SZ because of its relationship to functional outcomes is verbal memory (VM), which is particularly vulnerable to aging. Therefore, our aim was to investigate the trajectory of memory performance after 6 years in a sample of chronic individuals with SZ to bring further evidence for the two possible hypotheses (stability vs. progression).

Methods

We recruited 28 individuals with SZ (18 male, 10 female) from an outpatient clinic from a tertiary hospital in Porto Alegre, Brazil. These participants were part of a previous study, resulting in two point assessments of 6 years difference. Patients were stable and receiving pharmacological treatment. We conducted clinical interviews to collect sociodemographic and clinical data. Memory was assessed through the Hopkins Verbal Learning Test Revised (HVLT-R) on the two time points. Scores were transformed to z based on a healthy control sample. Analysis were conducted in the SPSS 18 and included general linear models and other exploratory analysis. The local ethics committee approved this study.

Results

On the first assessment, patients had 37.32(±11.28) years old, 10.54(±3.68) years of education, and 13.96 (±10.52) years since disease onset. Patients showed deficits in memory performance in both time points (T1: Z = -1.56(±1.19), T2: Z = -1.72(±1.19). However, there was no difference between baseline and follow-up after 5.78 (±0.9) years for the total immediate recall (p=.516). Additionally, we did not find significant effects of age and years of education to memory performance. Interestingly, duration of illness had a main effect predicting memory performance, however this was independent of time points (p=.003). Interestingly, 53.6% of patients decreased its performance on the follow-up, while 46.4% increased it. When we considered these two groups, we found an interaction of the time of assessment by increased/decreased trajectory in the prediction of memory performance (p = .001).

Discussion

Although we did not find differences between baseline and follow-up assessments, we found two different groups with diverse trajectories. The most recent studies in SZ have discussed the existence of these subgroups in the disorder. Our results didn’t showed evidence of impacts of both neurodevelopment or neuroprogression theories, the limited sample size may have influenced this. However, the two moment of assessment were with more than 10 years after the disease onset, adding to the compelling evidence that most of the cognitive deficits occur during early stages of the disorder.