People with severe covid-19 infections are more likely to be diagnosed with schizophrenia or other psychotic disorders than those who have not been infected with the virus, suggesting that covid-19 heightens the risk of schizophrenia.
Schizophrenia is a serious mental condition characterised by hallucinations, delusions and other cognitive impairments. It is unclear what causes it, though has suggested it may be triggered by viruses, such as the flu or even .
at West Virginia University and his colleagues analysed diagnoses of schizophrenia and similar conditions in people aged 17 to 70 who had been infected with covid-19. They collected data on more than 650,000 people from the US National COVID Cohort Collaborative. About 219,000 participants had moderate, severe or fatal covid-19 infections, and roughly 213,000 had tested negative for the virus. The remaining participants had acute respiratory distress syndrome (ARDS), a life-threatening lung condition unrelated to covid. No one had a history of schizophrenia, bipolar disorder, depression, personality disorders or trauma.
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The researchers examined how many participants went on to be diagnosed with schizophrenia, acute psychotic disorder or related conditions. They found that three weeks after infection, 2573 people were diagnosed with a psychotic condition, about half of whom had contracted covid-19. People who had covid-19 were roughly 4.6 times as likely to be diagnosed with a psychotic condition than those who tested negative for the virus. Those with ARDS were about 25 per cent less likely to be diagnosed with these conditions than those who tested negative.
About three months after infection, people with covid-19 were still 70 per cent more likely to be diagnosed with a psychotic disorder than people who tested negative or who had ARDS.
鈥淚 think this is perfectly in line with what has been hypothesised鈥�, which is that covid-19 heightens the risk of psychosis, says at the Karolinska Institute in Sweden, who was not involved in the research.
One idea for why this may be is that covid-19 increases inflammation in the brain, which in turn, leads to higher levels of a substance called kynurenic acid. Previous research has shown that people with schizophrenia and psychosis have elevated levels of kynurenic acid in their brains and spinal fluid, and Erhardt and her colleagues have seen similarly high levels in those with severe covid-19. She and others in the field hypothesise that kynurenic acid is a driver of psychosis.
鈥淚t鈥檚 really important to understand the relationship between the immune system and psychiatric symptoms, including cognition, to identify new pharmacological treatments so we can help these patients,鈥� she says.
medRxiv
