Mental illness: changes in incidence, prevalence, treatment and outcomes 2000-2018

Study type
Protocol
Date of Approval
Study reference ID
18_288
Lay Summary

There is increasing interest in the health inequalities experienced by individuals diagnosed with severe mental illness, commonly defined as schizophrenia, bipolar disorder, schizoaffective disorder and other non-organic psychotic illnesses. These individuals have been found to have a reduced life expectancy of up to 20 years. What is less clear is how other extremely disabling psychiatric disorders, such as severe depression, anxiety, post-traumatic stress disorder, eating disorders and personality disorders compare in terms of rates of premature death and physical health problems.

This study aims to describe the total number of people with a diagnosis of each of these disorders, and the number of new cases per year, over the period 2000-2018. It also aims to describe the physical health problems experienced by these patients, the rates of hospitalisation the drug and psychological treatment these individuals receive, and how rates of treatment have changed over this period. The study will also update previous research on death rates, physical ill health and causes of death in these groups, relative to the general population. We will examine the effects of psychotropic medications on these outcomes.

The results will lead to a better understanding of changes in mental illness burden over the past 18 years.

Technical Summary

For each of schizophrenia, bipolar disorder, schizoaffective disorder, other non-organic psychotic illnesses, severe depression, anxiety disorders, post-traumatic stress disorder, eating disorders and personality disorders we will describe the trends in incidence, prevalence, all-cause and cause specific mortality, comorbidity, hospitalisation, drug and psychological therapy receipt from 2000 to 2018.

Incidence rate will be defined as the number of disease onsets/sum of person-time at risk, prevalence as the number of cases/population size. Mortality, cause specific mortality, comorbidity and cause specific morbidity rate will be calculated as the number of new events/sum of person-time at risk. Mortality, cause-specific mortality, comorbidity, cause-specific morbidity and hospitalisation rates compared to the general population will be described by hazard ratios calculated using adjusted Cox proportional hazards regression and incidence rate ratios using Poisson regression. Drug treatment and psychological therapy will be described as incident treatments and prevalent treatments. We will examine how psychotropic drug treatment affects health outcomes and hospitalisation by comparing exposed vs unexposed individuals and exposed vs unexposed time periods in the same individual.

Health Outcomes to be Measured

• Incidence of:
schizophrenia, bipolar disorder, schizoaffective disorder, other non-organic psychotic illnesses, major depression, anxiety disorders, post-traumatic stress disorder, eating disorders, personality disorders

• Prevalence of:
schizophrenia, bipolar disorder, schizoaffective disorder, other non-organic psychotic illnesses, major depression, anxiety disorders, post-traumatic stress disorder, eating disorders, personality disorders

• Mortality rate in:
schizophrenia, bipolar disorder, schizoaffective disorder, other non-organic psychotic illnesses, major depression, anxiety disorders, post-traumatic stress disorder, eating disorders, personality disorders

• Disease specific morbidity in:
schizophrenia, bipolar disorder, schizoaffective disorder, other non-organic psychotic illnesses, major depression, anxiety disorders, post-traumatic stress disorder, eating disorders, personality disorders

• Receipt of drug treatment for:
schizophrenia, bipolar disorder, schizoaffective disorder, other non-organic psychotic illnesses, major depression, anxiety disorders, post-traumatic stress disorder, eating disorders, personality disorders

• Hospital admissions in:
schizophrenia, bipolar disorder, schizoaffective disorder, other non-organic psychotic illnesses, major depression, anxiety disorders, post-traumatic stress disorder, eating disorders, personality disorders

• Receipt of psychological treatment in:
schizophrenia, bipolar disorder, schizoaffective disorder, other non-organic psychotic illnesses, major depression, anxiety disorders, post-traumatic stress disorder, eating disorders, personality disorders

Collaborators

David Osborn - Chief Investigator - University College London ( UCL )
Joseph Hayes - Corresponding Applicant - University College London ( UCL )
- Collaborator -
Annie Jeffery - Collaborator - University College London ( UCL )
Antonio Lazzarino - Collaborator - University College London ( UCL )
Cini Bhanu - Collaborator - University College London ( UCL )
Eamon McCrory - Collaborator - University College London ( UCL )
Essi Viding - Collaborator - University College London ( UCL )
Francesca Solmi - Collaborator - University College London ( UCL )
Gabriele Price - Collaborator - Office for Health Improvement and Disparities
Graziella Favarato - Collaborator - University College London ( UCL )
Helen Bould - Collaborator - University of Bristol
Ian Wong - Collaborator - University College London ( UCL )
Irene Petersen - Collaborator - University College London ( UCL )
Jennifer Dykxhoorn - Collaborator - University College London ( UCL )
Justin Yang - Collaborator - University College London ( UCL )
Kate Walters - Collaborator - University College London ( UCL )
Kenneth Man - Collaborator - University College London ( UCL )
Laura Scolamiero - Collaborator - University College London ( UCL )
Leiah Kirsh - Collaborator - University College London ( UCL )
Mariam Humayun - Collaborator - University College London ( UCL )
Michelle Eskinazi - Collaborator - University College London ( UCL )
Naomi Launders - Collaborator - University College London ( UCL )
Naomi Warne - Collaborator - University of Bristol
Rosalind McAlpine - Collaborator - University College London ( UCL )
Sarah Hardoon - Collaborator - University College London ( UCL )

Linkages

HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;Mental Health Services Data Set (MHSDS);ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation