Children and adolescents who show persistent high levels of anxiety are more likely to become psychotic in their early 20s, according to a new study.

But treating early anxiety by targeting stress hormones and non-resolving inflammation during childhood and teenage years could help to reduce the risk of young adults going on to develop psychosis.

Experts at the University of Birmingham examined the link between persistent anxiety in childhood and adolescence with individuals with psychotic experiences (PE) or psychotic disorder (PD) at the age of 24.

They analysed data from the Avon Longitudinal Study of Parents and Children (ALSPAC) to create a picture of 3,889 children's mental health at eight, 10, 13 and 24 years-of-age.

Publishing their findings in Biological Psychiatry, the researchers reveal that individuals with persistent high levels of anxiety were more likely to develop PEs and PD at the age of 24 years.

Leading author Isabel Morales-Muñoz, from the University's Institute for Mental Health commented: "Persistent high levels of anxiety in childhood and adolescence are linked to subsequent psychosis, but we may be able to prevent psychosis by targeting and treating early anxiety.

"Early diagnosis and management of adolescent anxiety and possibly novel treatments targeted at inflammation could be key actions to unlock treatment strategies that reduce the risk of children and adolescents going on to develop psychosis."

Psychotic disorders are among the leading causes of disability and affect 31% of people in England. Evidence suggests both genetic and environmental risk factors, including deprivation, childhood trauma and minority status, contribute to their development.

Individuals who develop psychosis are more likely to show socio-emotional and behavioural problems in childhood, but whether childhood anxiety is associated with subsequent psychosis is still under-investigated.

The senior author of the study, Rachel Upthegrove commented: "Childhood and adolescence is the core risk phase for developing anxiety disorders which become risk factors for general mental disorders in adulthood.

"We identified a group of children and adolescents who experience persistent and high anxiety levels, and these could be the individuals at higher risk for later mental disorders, including psychosis."

Researchers found more robust associations of persistent high levels of anxiety with PD than with PEs.

This suggests that persistent childhood and adolescent anxiety may form a better indicator of the development of future formal psychotic disorder, while PEs, which are far more common in the population than PDs, constitute a more diverse group.

The experts believe that PEs may associate with a wider range of potential risk factors in young adulthood, such as sex and cannabis use.

Their findings indicate that associations of persistent high levels of anxiety with psychosis at 24 years could be specific to this mental disorder, as no associations with other relevant disorders, such as hypomania, phobias or substance abuse were found.