Risk factors for the development of mental illnesses: an agile scoping review

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Introduction

Understanding what factors can increase people’s risk of developing mental illness is a necessary first step to enable the effective targeting of preventive interventions. This scoping report provides an overview of the available secondary evidence on the risk factors for predicting the development of diagnosable mental illnesses and was commissioned to help inform updates to Wales’ Mental Health Strategy.

Main points

How up to date is this evidence?

We conducted this review in 2023 and identified relevant evidence published between 2013 and 2023.

What we found

Our searches identified many umbrella reviews and systematic reviews of primary studies published in the last 10 years focusing on a range of mental illnesses in different population groups. All the umbrella reviews identified focused on non-genetic risk factors for mental illnesses, and none focused on genetic causes. The evidence in this review was identified from a meta-umbrella systematic review of umbrella reviews focussing on non-genetic risk or protective factors for any ICD/DSM mental disorders

• The most convincing (Class I evidence) risk factors for dementia included type 2 diabetes mellitus, depression, and low frequency of social contacts
• For non-organic psychotic disorders, the most convincing risk factor was clinical high-risk state for psychosis
• For opioid use disorders, the most convincing risk factor was tobacco smoking
• Risk factors for depressive disorders included widowhood, sexual dysfunction, three to five metabolic risk factors, childhood physical and sexual abuse, job strain and obesity
• For attention deficit/hyperactivity disorder (ADHD), the most convincing risk factors were maternal pre-pregnancy obesity, maternal overweight pre/during pregnancy and maternal smoking during pregnancy
• The most convincing risk factor for autism spectrum disorder was maternal overweight pre/during pregnancy.

Technical information

We produced an agile scoping review which provides a broad overview of the evidence on the topic of risk factors for predicting the development of diagnosable mental illnesses.

Glossary

ICD: International Statistical Classification of Diseases and Related Health Problems (ICD) serves a broad range of uses globally and provides critical knowledge on the extent, causes and consequences of human disease and death worldwide via data that is reported and coded with the ICD. 

DSM: The Diagnostic and Statistical Manual of Mental Disorders (DSM) is the standard classification of mental disorders used by mental health professionals in the United States. 

Non-organic psychotic disorders: refers to psychotic experiences that occur in the absence of identifiable organic brain pathology

Metabolic risk factors: conditions and/or traits that increase the likelihood of developing metabolic syndrome, type 2 diabetes, and cardiovascular disease

Umbrella review: An umbrella review is a systematic collection and assessment of multiple systematic reviews and meta-analyses on a specific research topic

Systematic review: A review that summarises the evidence on a clearly formulated review question according to a predefined protocol, using systematic and explicit methods to identify, select and appraise relevant studies, and to extract, analyse, collate and report their findings. It may or may not use statistical techniques, such as meta-analysis