Effect of Covid-19 infection on the developing brain: psychosis proneness and working memory activation

Researchers have been investigating the effects of Covid-19 infection since late 2019. Symptoms caused by the SARS-Cov-2 virus varied from respiratory system failure to fatigue, brain fog and headaches. Studies showed that the infection leads to cognitive impairment and psychotic-like symptoms even after recovery. Literature has focused on hospitalized adult patients, and there is less information on how the developing brain exposed to the virus is affected. To address these gaps in the literature we investigated whether Covid-19 can be a risk factor for psychosis in adolescents and young adults. Forty individuals who were infected with Covid-19 and recovered at least two and at most four months before and 36 demographically matched controls were recruited in the study. Positive PCR test results confirmed the infection status of the participants. Subclinical psychosis was assessed using the Community Assessment of Psychic Experience (CAPE-42) questionnaire and the Structured Interview of Schizotypy - Revised (SIS-R) was used to assess psychotic-like symptoms. A functional magnetic resonance imaging was conducted during a well-known working memory task to investigate activation patterns. The working memory task involved seven tasks and a control motor task. Verbal fluency performance was assessed in both phonetic and semantic categories. In order to control for the confounding effects of additional environmental risk factors for psychosis, paternal age, years of urban upbringing, cannabis exposure, and ethnicity were also considered. The findings revealed that although the two groups did not differ across different dimensions of the CAPE-42, the infected group had higher restricted affect and referential thoughts of being watched. Individuals infected with SARS-Cov-2 performed worse in both categories of the verbal fluency task. fMRI analysis revealed that individuals infected with the SARS-Cov-2 virus showed activation differences in the prefrontal cortex, medial temporal gyrus, middle frontal gyrus, and inferior parietal gyrus. Higher performance in the verbal fluency task predicted greater activation during the working memory task. These results suggest that exposure to the Covid-19 infection during brain development can be an environmental risk factor for psychosis.