Good mental health is widely accepted as being instrumental to quality of life, but even people who usually enjoy good mental health may face changing life circumstances that can trigger episodes of poor mental health. The deeper problem with poor mental health is that the burden is often heavy in personal, social, economic and healthcare terms, potentially reaching into every part of the life experience.
Mental health is affected by biopsychosocial factors including socio-demographic, health behaviour and physical health factors. For example, previous research has established that poorer mental health outcomes are associated with being female, having low socio-demographic status, engaging in unhealthy behaviours and having poor physical health. The aim of the current study is to explore the contribution of biopsychosocial factors of this type to the mental health of women across the lifespan.
To achieve this aim it was necessary to consider measurement issues affecting components of mental health, such as the association between anxiety and depression, and the effect of mental health on the reporting of life events, selected as an example of one of the more complex biopsychosocial correlates of mental health. The associations between mental health and biopsychosocial factors were examined cross-sectionally and longitudinally using data from the Australian Longitudinal Study on Women’s Health (ALSWH).
Analyses were conducted on the ALSWH data from the 1996 and 2000 surveys of younger women (aged 18-23 years in 1996, n=14779); 1996, 1998 and 2001 surveys of mid-age women (aged 45-50 years in 1996, n=14099); 1996, 1999 and
2002 surveys of older women (aged 70-75 years in 1996, n=12940). Women were sent postal questionnaires containing 300 to 500 items on each occasion.
Latent trait analysis was used to establish that the items from the Goldberg Anxiety and Depression Scale (GADS) formed a single factor of anxiety and depression among older women. Supporting evidence for the use of a single factor included the substantial correlation between sum scores from the anxiety subscale and the depression subscale (r=0.65). Further, it was established that retaining the physical health items in GADS did not diminish the psychometric properties of the scale. This was shown, for example, by the Cronbach’s alpha of 0.84 for sum scores both with and without the physical health related items included.
The complex relationship among the mental health measures and biopsychosocial factors analysed in this study are typified by the effects of mental health on the reporting of life events and the corresponding effects of life events on mental health. Clear evidence was found that mental health affected the reporting of life events and correspondingly that the number of life events experienced in a twelve months period was predictive of poor mental health.
Cross-sectional associations between mental health and socio-demographic, health behaviour and physical health factors were investigated using data from three age cohorts of women and from several measures of mental health. The measures of mental health used were: the multi-item measures Medical Outcome Short Form (36-item) Health Survey (SF-36) Mental Health Subscale (MHI-5), Center for Epidemiological Studies Depression scale (CESD-10) and GADS; and single item measures based on respondents reporting the symptom of depression, the symptom of anxiety, a doctor’s diagnosis of depression and a doctor’s diagnosis
of anxiety. The cross-sectional analyses undertaken established the consistency of effects across measures and age cohorts. Women from the three cohorts experiencing good mental health tended to be socially advantaged (for example, finding it easy to manage on the income available), had positive health behaviours (for example, being physically active) and good physical health (for example, reporting few physical symptoms).
The next step was to explore trajectories of mental health (measured by MHI-5) over time. Women from the three cohorts reporting improved mental health tended to be socially advantaged and to have good physical health. For mid-aged women across the three surveys, 73% reported consistently good mental health (MHI-5 greater than 53), 4% reported consistently poor mental health and 23% reported mental health that varied over time. Throughout the study period mid-age women who had consistently poor mental health or varying mental health (compared to those with consistently good mental health) were more likely to be un-partnered, become re-partnered or become un-partnered; report difficulty managing on their income in at least one of the surveys; continually been a smoker, adopted or quit smoking; report being physically inactive in at least one of the surveys; report many GP visits in at least two of the surveys; report many physical health symptoms in at least one of the surveys. Further, women who had consistently poor mental health (compared to those with varying mental health) were more likely to have reported difficulty managing on their income in at least two surveys, reported seeing a GP many times in all three surveys, or reported many physical health symptoms in at least one survey.
To verify the consistency of the results, variant (changeable) and invariant (stable) factors affecting mid-age women’s mental health across three surveys were examined. Factors affecting mental health over time included change (or no change) in: partner status, ability to manage on the available income, smoking, physical activity, visits to a general practitioner, and number of physical symptoms. Women with positive invariant states (such as always reporting few physical symptoms) had the best mental health across the three surveys, women with negative invariant states (such as always reporting many physical symptoms) had the poorest mental health across the three surveys, and women reporting a variant state (such as going from few to many physical symptoms) lay somewhere between these two extremes across the three surveys.
The current study adds to the understanding of the biopsychosocial characteristics associated with mental health. The importance of studying changes in mental health for women over extended periods of time (2-5 years) within a population framework was established. Despite the prevalence of poor mental health remaining relatively stable over time, the mental health of some women was shown to change over time, in some cases quite markedly, according to their biopsychosocial characteristics. Australian women experiencing poor or declining mental health were found to be more socially disadvantaged, and have more negative health behaviours and poorer physical health. Importantly, measuring mental health on a continuum permitted sub-clinical levels of mental ill-health to be considered. The current study points to the importance of support and intervention well before mental health issues escalate to clinical levels.