The authors have declared that no competing interests exist.
Conceived and designed the experiments: PK EP ST. Performed the experiments: PK EP. Analyzed the data: PK MS EP. Wrote the paper: PK MS EP ST.
Despite widespread acceptance of the ‘biopsychosocial model’, the aetiology of mental health problems has provoked debate amongst researchers and practitioners for decades. The role of psychological factors in the development of mental health problems remains particularly contentious, and to date there has not been a large enough dataset to conduct the necessary multivariate analysis of whether psychological factors influence, or are influenced by, mental health. This study reports on the first empirical, multivariate, test of the relationships between the key elements of the biospychosocial model of mental ill-health.
Participants were 32,827 (age 18–85 years) self-selected respondents from the general population who completed an open-access online battery of questionnaires hosted by the BBC. An initial confirmatory factor analysis was performed to assess the adequacy of the proposed factor structure and the relationships between latent and measured variables. The predictive path model was then tested whereby the latent variables of psychological processes were positioned as mediating between the causal latent variables (biological, social and circumstantial) and the outcome latent variables of mental health problems and well-being. This revealed an excellent fit to the data, S-B χ2 (3199, N = 23,397) = 126654·8, p<·001; RCFI = ·97; RMSEA = ·04 (·038–·039). As hypothesised, a family history of mental health difficulties, social deprivation, and traumatic or abusive life-experiences all strongly predicted higher levels of anxiety and depression. However, these relationships were strongly mediated by psychological processes; specifically lack of adaptive coping, rumination and self-blame.
These results support a significant revision of the biopsychosocial model, as psychological processes determine the causal impact of biological, social, and circumstantial risk factors on mental health. This has clear implications for policy, education and clinical practice as psychological processes such as rumination and self-blame are amenable to evidence-based psychological therapies.
Mental health problems affect one person in every four, making them the leading cause of disability
It is universally accepted that biology, the environment, and adverse life events collectively cause mental problems
From a biological perspective, mental health problems result from genetically transmitted physical abnormalities
Scholarly dispute is most evident in differing accounts of the role played by psychological factors
The alternative to the strictly biological view is that biological factors, social factors and other environmental or life events lead to mental health problems through their conjoint effects on psychological processes, and these are the final common pathway to mental ill-health
These formed the basis for our covariance modeling.
Here we report on the first empirical test of the relationships between the key elements of the biospychosocial model of mental ill-health based on a representative population sample and using structural equation modeling (SEM).
This study complies with the guidelines of the 1964 Declaration of Helsinki. Ethical approval was obtained by the University of Liverpool’s School of Population, Community and Behavioral Science Research Ethics Committee May 2009.
Participants were 32,827 (age 18–85 years) self-selected respondents to an open-access online battery of questionnaires (“The Stress Test”), approved by the University of Liverpool Committee on Research Ethics and conducted in accordance with the ethical standards of the 1964 Declaration of Helsinki. In order to determine if the sample was representative of the UK population, where comparable demographic data existed, UK respondents were compared to national data
% ( |
|
Ethnic group | |
White - British, Irish, Other | 92·8 (25,434) |
Black Minority Ethnic | 5·8 (1,612) |
Rather not say or missing | 1·3 (351) |
Highest level of schooling achieved | |
Did not complete schooling | 2·2 (601) |
In education until age 18 | 24·7 (6,766) |
Degree or professional qualification | 73·1 (20,030) |
Occupational Status | |
In education | 11·4 (3,109) |
In employment | 73·7 (20,195) |
Other | 14·9 (4,093) |
Total gross annual or weekly household income | |
Up to £30,000 to £39,999 ($49,000–$65,000)/annum | 51·9 (14,206) |
Above £30,000 to £39,999 ($49,000–$65,000)/annum | 36·0 (9,851) |
Don’t know/prefer not to say or missing | 12·1 (3,340) |
Estimated parents income whilst growing up | |
Lower than 50% population | 50.8 (13,913) |
Higher than 50% population | 49·2 (13,484) |
Relationship status | |
In a relationship | 73·2 (20,062) |
Single | 26·8 (7,335) |
Number of children | |
None | 53·7 (14,717) |
One or more | 46·3 (12,680) |
The Stress Test was promoted via multi-media formats (TV, radio and online) and launched on BBC Radio 4′s ‘All in the Mind; a flagship documentary focusing on issues of the human mind. The test’s URL [
Measures were selected on the basis of theoretical principles and empirical research to provide indicators of latent constructs representative of the components of the biopsychosocial model
Indicators of the circumstantial component included recent life events measured using the List of Threatening Experiences Questionnaire
SEM relies on the identification and subsequent analysis of latent variables or factors
A two-step analytical approach was used, conducted using the EQS structural equation modeling (SEM) program
Because of the multivariate kurtosis in the data, goodness of fit of models was evaluated with the adjusted robust comparative fit index (RCFI) based on the Satorra-Bentler χ2 statistic
In the development of the model path, elimination was monitored via successive improvement of the χ2, RCFI, and RMSEA statistics. This ‘measurement model’ phase of analysis will be reported in detail elsewhere (“Establishing the construct validity and factor structure of latent psychosocial variables in psychiatric research”, Pontin et al., submitted). Once the factor structure was established, the predictive path model was tested whereby the latent variables of psychological processes were positioned as a mediating variable between the causal latent variables (biological, social and circumstantial) and the outcome latent variables of mental health problems and well-being.
The initial CFA established that we had a robust measurement model with latent factors comprising all of the key components of the hypothesis under test, S-B χ2 (3,199, N = 27,397) = 126,654·8,
Results of a structural equation model testing the mediating effects of the psychological processes of response style and self-blame on the contribution of familial mental health history, relationship status, income and education, social inclusion and life events on mental health problems and well-being, with S-B χ2 (3,199, N = 27,397) = 126,654·8, p<·001; RCFI = ·97; RMSEA = ·04 (·038–·039). The path diagram shows completely standardised robust parameter estimates which represent the relative contribution of each latent factor to the model. All coefficients are statistically significant, p<·001. Latent factors are represented by ovals. The double headed arrow between mental health problems and well-being represents the correlations between these latent constructs.
Latent factors & measured variables | Standardised loading |
Mother diagnosed with a mental health problem | ·46 |
Father diagnosed with a mental health problem | ·33 |
Sibling diagnosed with a mental health problem | ·48 |
More than sibling diagnosed with a mental health problem | ·38 |
Relationship with friends | ·90 |
See other relative/friend weekly | ·43 |
Relationship with family | 4·77 |
See parent weekly | ·06 |
See sibling weekly | ·05 |
How do you best describe your social activities | ·87 |
Attend an evening class | ·12 |
Given up time for charity or local group | ·27 |
Involved in club/organisation/religious group | .33 |
Participated in sports/physical activity | ·37 |
Go to the cinema | ·28 |
In the past I believe I was physically abused | ·49 |
In the past I believe I was sexually abused | ·35 |
In the past I believe I was emotionally abused | ·67 |
In the past I believe I was bullied at school | ·44 |
Total number of life-events | ·55 |
Parental income | ·37 |
Current income | ·30 |
Educational attainment | ·37 |
Relationship status | ·61 |
Number of children | ·41 |
Latent factors & measured variables | Standardised loading |
Think of shortcomings, failings, faults & mistakes | ·68 |
Think about how angry with self | ·65 |
Think about something to make myself feel better | ·29 |
Think about how passive & unmotivated you feel | ·75 |
Try to understand self by focusing on depressed feelings | ·61 |
Isolate yourself and think of reasons feel sad | ·63 |
Think about how you don’t feel up to doing things any more | .80 |
Do something that has made feel better in past | ·64 |
Think I’m going to do something to make myself feel better | ·60 |
Make a plan to overcome a problem | ·58 |
Try to understand self by focusing on depressed feelings | ·30 |
Remind yourself that feelings won’t last | ·51 |
Drink alcohol excessively | ·47 |
Take recreational drugs | ·32 |
Do something reckless or dangerous | ·56 |
Internal attributions (self-blame) | .33 |
Latent factors & measured variables | Standardised loading |
Have you felt anxious or on edge | ·57 |
Have you been worrying a lot | ·67 |
Have you been irritable | ·53 |
Have you had difficulty relaxing | ·66 |
Have you been sleeping poorly | ·46 |
Have you had a headache or neck ache | ·35 |
Trembling/tingling/dizzy spells/sweating/ | ·47 |
Have you been worried about your health | ·48 |
Have you had difficulty falling asleep | ·41 |
Have you had low energy | ·56 |
Have you had loss of interest | ·64 |
Have you lost confidence in yourself | ·70 |
Have you felt hopeless | ·70 |
Have you had difficulty concentrating | ·58 |
Have you lost weight (due to poor appetite) | ·22 |
Have you been waking early | ·19 |
Have you felt slowed up | ·58 |
Have you tended to feel worse in the morning | ·38 |
Latent factors & measured variables | Standardised loading |
Do you feel depressed or anxious ? | ·04 |
Do you feel able to enjoy life | ·80 |
Do you feel you have a purpose in life | ·70 |
Do you feel optimistic about the future | ·76 |
Do you feel in control of your life | ·78 |
Do you feel happy with yourself as a person | ·80 |
Are you happy with your looks and appearance | ·60 |
Do you feel able to live your life the way you want | ·77 |
Are you confident in your own opinions and beliefs | ·54 |
Do you feel able to do the things you choose to do | ·71 |
Do you feel able to grow and develop as a person | ·73 |
Are you happy with yourself and achievements | ·72 |
Are you happy with friendships/relationships | .16 |
Are you happy with your physical health | ·63 |
Are you happy with the quality of your sleep | ·60 |
Are you happy with your ability to perform daily living activities | ·77 |
Are you happy that you have enough money to meet your needs | ·51 |
Are you happy with your opportunity for exercise/leisure | ·59 |
Are you happy with access to health services | ·48 |
Are you happy with your ability to work | ·65 |
Are you happy with your personal and family life | ·74 |
Are you happy with your friendships and personal relationships | ·93 |
Are you comfortable about way you relate connect with others | ·74 |
Are you happy with your sex life | ·50 |
Are you able to ask someone for help with a problem | ·67 |
Notes: Standardised loadings of measured variables on their respective latent factors for the structural model, S-B χ2 (3,199, N = 27,397) = 126,654·8,
The second step in the analysis tested how the latent factors revealed in the CFA to represent key elements of the biopsychosocial model
Initially, we tested a default model, exploring the relationships between putative causal factors (familial mental health history, relationship status, income and education, social inclusion and life events) with well-being and mental health problems, without the mediating role of psychological processes. This revealed a poor fit to the data, χ2 (3,205,
Next, we used SEM to test a model with the same latent factor predictors, but including the hypothesised mediating role of psychological processes (see
Structural equation models can be used to infer causality more robustly than conventional correlational analyses, as they account for interactions between factors
Direct | Mediated | Total | |
Familial mental health history | 1·30 | 1·50 | 2·80 |
Relationship status | 0·08 | 0·39 | 0·43 |
Income and education | 1·26 | 0·92 | 2·18 |
Social inclusion | 0·36 | 0·04 | 0·40 |
Life events | 2·11 | 2·36 | 4·47 |
Notes: Parameter estimates representing the effects of familial mental health history, relationship status, income and education, social inclusion and life events on mental health problems, with and without the mediating effect of psychological processes of response style and self-blame.
Direct | Mediated | Total | |
Familial mental health history | 1·28 | 1·26 | 2·54 |
Relationship status | 0·39 | 0·29 | 0·68 |
Income and education | 0·07 | 0·77 | 0·84 |
Social inclusion | 1·00 | 0·04 | 1·04 |
Life events | 1·79 | 1·98 | 3·77 |
Notes: Parameter estimates representing the effects of familial mental health history, relationship status, income and education, social inclusion and life events on well-being, with and without the mediating effect of psychological processes of response style and self-blame.
These results show that life events (childhood abuse and bullying, and stressful life events in adulthood) were the strongest direct predictors of mental health problems (depression and anxiety). A familial history of mental health problems and social status (income and education) were the next most significant direct predictors of mental health problems - and here it should be remembered that genetic or biological factors are not the only vectors for the familial transmission of mental health problems
As hypothesised, however, the key psychological processes of response style and self-blame were significant mediators of all these paths. The overall fit of the model - its ability to explain the data reported in this population – was significantly improved by the inclusion of psychological processes as mediators in the hypothesised relationship between biological factors, life events, and environmental challenges, and mental health and well being. Moreover, life events and familial mental health history were the most significant direct predictors of mental health problems. However, the causal pathways involving the mediation of response style and self-blame were stronger predictors than direct paths. This was also true for the (smaller) effect of relationship status. The direct effects of social status (income and education) and social inclusion on mental health problems remained more significant than the mediated routes, but in each case there was a significant mediation effect.
A broadly similar pattern was observed in the prediction of well-being. Again, life events were the strongest predictors of well-being, followed by a familial history of mental health problems and social inclusion. Again, psychological processes were very significant mediating factors. This mediation effect was most significant in the path involving life-circumstances and social status (income and education).
Our results demonstrate that psychological processes of response style (specifically a greater tendency to ruminate) and self-blame (or an internal attributional style for negative events) powerfully determine the impact of familial histories of mental health problems, life events and traumas, and social deprivation in the aetiology of depression and anxiety and in the maintenance of well-being. This study is the first multivariate empirical test of specific and previously published hypotheses
Our results did not support a fully mediated model (that is, with no residual direct effects), but this is entirely unsurprising. Mental health and well-being can be safely assumed to be the result of a huge number of causal factors with a large number of mediating psychological processes. In this study, we examined only two of the very many psychological processes hypothesised to be important in mental health. Nevertheless, we are confident both that these findings are themselves robust and that other psychological processes would also act as mediators in causal paths similar to those revealed here.
The present study was designed as an empirical test of a hypothesised set of relationships derived from previously published theoretical research
There was also a potential element of self-selection in the present study, given the recruitment strategy and the on-line methodology. However, although more of our participants were white, had slightly higher earnings, and were better educated than the England and Wales average
These results support a significant revision of the biopsychosocial model. Instead of regarding these three causal agents as co-equal partners in the aetiology of mental health problems, these results demonstrate that the impact of physical and social causes on mental health and well-being outcomes is mediated by psychological processes. In other words, psychological processes determine the causal impact of biological, social, and circumstantial risk factors.
These findings and this interpretation have significant implications. Reductionist biological accounts of mental health have been robustly criticised on scientific, ethical, and practical grounds
We thank staff of BBC LabUK for their support for the development and conduct of the study, and J. Rees for critical discussions and reading of the manuscript.