News Release 

Thirty risk factors found during and after pregnancy for children developing psychosis

NIHR Maudsley Biomedical Research Centre

More than 30 significant risk factors have been identified for the development of psychotic disorders in offspring in research led by the NIHR Maudsley BRC. It is the first comprehensive meta-analysis of pre- and perinatal risk factors for psychosis in nearly 20 years.

These prenatal and perinatal environmental risks, meaning risks during pregnancy and seven days after birth, have a significant effect on the likelihood of their child developing psychosis. As a result, researchers suggest women at risk should be screened early on in their pregnancy so that those with these identified risks can be given additional support. The findings have been published today (Tuesday 24 March 2020) in Lancet Psychiatry.

Gathering data from 152 studies published between 1977 and July 2019 and looking at 98 factors, researchers identified 30 significant risk factors and five protective factors.

Psychotic disorders are severe mental illnesses which cause abnormal thoughts, such as hallucinations or delusions, but they can affect each person in different ways. In 2014, a survey found the 6% of people in England said they had experienced at least on symptom of psychosis.

Factors can be split into four categories; parental and familial, pregnancy, labour and delivery, and foetal growth and development. Significant protective factors were mothers being aged between 20 - 29, first time mothers and higher birthweights in babies.

For risk factors, previous mental health conditions in either parents, nutritional deficiencies, low birthweight and giving birth in the colder months were found to increase the probability of a child developing psychosis. Age related risk factors were either parent being under 20, mothers between 30-34 and fathers over 35. Researchers also found that a lack of prenatal care visits poses a risk and marked this as a potential risk factor to combat with outreach campaigns.

This study confirmed the importance of factors during labour and delivery, such as a foetus' brain being deprived of oxygen and ruptured membranes, which are historically among the most consistently implicated risk factors. Conversely, despite previous studies focusing on infections during pregnancy causing psychosis, this study found significant associations only for HSV-2 and maternal infections 'not otherwise specified' and found that influenza had no indication of a significant effect.

This study will help guide future research in the field of psychosis, as well as form the basis for psychosis risk prediction models which could advance preventative strategies.

Dr Paolo Fusar-Poli, Reader in Psychiatry and Youth Mental Health at Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London said: 'This study is confirming that psychotic disorders originate in the early phases of life with the accumulation of several environmental risk factors during the perinatal and prenatal phases. The results of this study will advance our ability to detect individuals at risk of developing psychosis, predict their outcomes and eventually offer them preventive care.'

Whilst this study focused on the environmental factors there may also be genetic or epigenetic risks factors that are implicated in the onset of psychosis.

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Notes to editors

To find out more about or to arrange interviews please contact the Communications team at NIHR Maudsley BRC:

  • Alex Booth, Communications and Engagement Manager, NIHR Maudsley Biomedical Research Centre, Tel 020 7848 0495 alex.booth@kcl.ac.uk
  • Serena Rianjongdee, Communications and Engagement Officer, NIHR Maudsley Biomedical Research Centre, Tel 020 7848 2137 serena.rianjongdee@kcl.ac.uk

Notes to editors

The National Institute for Health Research (NIHR) is the nation's largest funder of health and care research. The NIHR:

  • Funds, supports and delivers high quality research that benefits the NHS, public health and social care
  • Engages and involves patients, carers and the public in order to improve the reach, quality and impact of research
  • Attracts, trains and supports the best researchers to tackle the complex health and care challenges of the future
  • Invests in world-class infrastructure and a skilled delivery workforce to translate discoveries into improved treatments and services
  • Partners with other public funders, charities and industry to maximise the value of research to patients and the economy

The NIHR was established in 2006 to improve the health and wealth of the nation through research, and is funded by the Department of Health and Social Care. In addition to its national role, the NIHR supports applied health research for the direct and primary benefit of people in low- and middle-income countries, using UK aid from the UK government.

This work uses data provided by patients and collected by the NHS as part of their care and support and would not have been possible without access to this data. The NIHR recognises and values the role of patient data, securely accessed and stored, both in underpinning and leading to improvements in research and care. http://www.nihr.ac.uk/patientdata

About King's College London and the Institute of Psychiatry, Psychology & Neuroscience

King's College London is one of the top 10 UK universities in the world (QS World University Rankings, 2018/19) and among the oldest in England. King's has more than 31,000 students (including more than 12,800 postgraduates) from some 150 countries worldwide, and some 8,500 staff.

The Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's College London is the premier centre for mental health and related neurosciences research in Europe. It produces more highly cited publications in psychiatry and mental health than any other university in the world (Scopus, 2016), with 21 of the most highly cited scientists in this field. World-leading research from the IoPPN has made, and continues to make, an impact on how we understand, prevent and treat mental illness and other conditions that affect the brain. http://www.kcl.ac.uk/ioppn

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