European researchers have found 30 pre- and perinatal risk factors for psychosis, as well as a few protective factors, in the first major systematic review and meta-analysis on the topic in two decades.

Examining 152 case-control and cohort studies, they have included factors associated with the parents’ age and mental health, pregnancy, labour and delivery, as well as fetal growth and development in their analysis.

Here are the 10 risk factors that appear to have the largest effects:

Meanwhile, maternal age between 20 and 29, being nulliparous and a birthweight above 3500g all reduce the risk of a child developing psychosis in later life, the researchers say.