Attention problems in childhood could act as a “middleman”, or an intermediary, between a genetic risk for mental illness and experiencing psychosis-like symptoms — a feature of mental conditions such as schizophrenia and mania phase of bipolar disorder, according to a study.

Psychosis is a mental state in which one loses touch with reality. Symptoms include harbouring delusions and experiencing hallucinations.

Problems with one’s ability to concentrate, or one’s attention span, are known to be one of the earliest preceding stages of psychosis.

However, researchers at the University of California Los Angeles (UCLA) Health, US, have found that having attention issues as a child explained about 4-16 per cent of the link between one’s genetic risk for psychiatric disorders and experiencing psychosis-like symptoms.

“If attention completely explained the relationship between genetic predisposition and psychotic-like experiences, that percentage would be 100 per cent,” Sarah Chang, a neuroscience graduate student at the UCLA Health and co-first author of the study published in the journal Nature Mental Health, said.

“While there are many risk factors for psychosis, the mechanisms through which these risk factors operate, particularly during this developmental risk period for psychosis, are not well understood – and that’s where our paper comes in,” Chang said.

The researchers also found that a higher genetic risk for mental and cognitive disorders was related with more severe psychotic experiences and greater attention issues.

For their analysis, the team used cognitive, brain and genetic data from more than 10,000 participants from the ongoing Adolescent Brain and Cognitive Development (ABCD) study in the US, which is examining brain development in nearly 12,000 youth starting at age of nine and following them into early adulthood.

Specifically, the researchers looked at how the youths’ risk for psychotic-like experiences changed based on their attention span and genetic risk.

“We have known for a very long time that attention problems are some the earliest precursors of psychosis,” lead author Carrie Bearden, a professor at UCLA Health.

“Taking a different approach of looking at this large, typically developing youth cohort we find a really strong association with broad neurodevelopmental risk that was most strongly linked to psychotic symptoms. Attentional variability appears to be a mediator that links the genetic liability and those symptoms,” Bearden said.