Participants with SMI rated their global physical health and their perceived risk of suffering from a myocardial infarction similarly to people with non-psychotic mental illness. Indeed, less than half of them expressed concern about the possibility of having sub-optimal physical health or that they may be at risk of developing serious physical health illnesses. A growing body of research postulates that SMI itself may be a risk factor for CHD, stroke and diabetes [6
] in excess of the risks carried by the general population, and to a lesser extent in excess of those with people with non-psychotic mental illness [9
]. Nevertheless people with SMI may not be entirely aware of these increased physical health risks. This finding is consistent with our previous work suggesting that people with SMI are likely to have poor level of knowledge regarding specific risks factors for CHD [18
]. Similar findings have been reported with respect to the knowledge about diabetes amongst people with SMI and co-occurring type 2 diabetes compared to people with non-psychotic mental illness as well as the general population [19
A more surprising finding is the relatively optimistic judgement about their physical health demonstrated by participants with non-psychotic mental illness in our sample, despite that people with anxiety and depression have consistently been shown to have higher levels of physical health disability [33
]. The level of neuroticism inherent to these illnesses is also associated with excess reporting of somatic symptoms [35
] and a propensity to seek medical assistance for physical symptoms [9
]. At the same time, it also known that people in the recovery phase from depression and anxiety demonstrate less physical disability [33
], which may also extend to curtailed knowledge and apprehension about physical health. It is therefore possible that our sample may have contained a large proportion of participants in the recovery phase of their illness, in addition to those with personality disorder, diluting the concern about physical health that would have otherwise been expected from this participant group.
People with SMI in our study do not consider their physical health to be one of the main priorities in their life. On the other hand, given the chronic nature and severity of their mental illness, they may understandably reserve a greater proportion of their energy to attempt to optimise their mental health. In other words, people with SMI may recognise the great burden that their mental illness can impose on their quality of life [36
], while overlooking the potential contribution of their physical health to this impaired quality of life. In contrast, given the preoccupation with physical illness usually demonstrated by people with non-psychotic mental illness [34
], our participants in this sub-group viewed their physical health as one of their greatest priorities. This finding is sharply incongruent with our other result suggesting lower than expected levels of awareness about physical health by this group of individuals. A plausible explanation could be that the broader and more in-depth nature of the questionnaire utilised to capture this aspect of behaviour was more successful at eliciting physical health concern in these people.
People with SMI and non-psychotic mental illness equally view their mental illness as a major barrier to improving their physical health. Our sample of participants in the latter category was drawn from a secondary care out-patients service, where the degree of psychiatric morbidity is likely to have been at the more severe end of the illness spectrum. This may have been a major contribution our finding. We were unable to explicitly bring to light any other specific barriers to improving physical health in either group of participants. A recent thorough narrative review of incentives and barriers to healthy living or lifestyle interventions for people with SMI did highlight the relatively sparse research specifically designed to address these issues [37
]. However, identified barriers include psychiatric symptoms, in line with our results, as well as adverse effects of medications and negative attitudes of healthcare professionals.
Similar to findings from previous studies [38
], people with SMI were also more likely to be smokers, contributing to their risks of physical disease. Additionally, all but one participant reported lack of exercise and poor diet. In fact, in a previous UK study amongst people with SMI, only one-third of participants with SMI reported eating at least one fruit a day [39
]. Physical inactivity and poor diet in the form of low fibre and high saturated fat intake have already been postulated to partly explain the increased CHD-risk associated with SMI irrespective of medication treatment and socio-economic variables [6
]. This combination of low priority given to their physical health, lack of awareness about increased risk to physical health and increased health-related risk behaviours, poses a significant challenge to improving the physical health in this population group. Signs of early CHD and other related problems such as hypertension and blood lipid abnormalities can often go unnoticed unless directly monitored [40
]. As those who suffer with SMI are unaware of their increased physical health risks, efforts need to be made in order to increase the knowledge amongst people with SMI related to these risks and subsequently improve uptake of health monitoring tests. Additionally, findings from other studies suggest that people with SMI and chronic somatic disease are likely to have an even poorer quality of life than people with SMI alone [41
]. All of these factors therefore highlight the importance of implementing early behavioural lifestyle interventions aimed at improving physical health outcomes for this group of people. Evidence from studies amongst people with schizophrenia also suggests that these interventions can indeed be effective, for instance in reducing antipsychotic-induced weight gain [42
We did not evaluate cognitive functioning in our participants. However, previous work has shown that the knowledge about diabetes in people with SMI may be directly correlated with their level of cognitive ability [19
]. Strategies aimed at increasing the awareness of the physical health risks in people with SMI should therefore also pay recognition to these cognitive deficits, and ensure that cognitive loads are maintained to a minimum.
Lack of motivation as a negative symptom of psychotic illnesses could be implicated in the poor physical health of people with SMI, and earlier small studies evaluating motivation to exercise seem to imply so [37
]. However our findings suggest that there is no difference in people with SMI from those with non-psychotic mental illness with respect to their desire to change high-risk lifestyle behaviours, namely smoking, poor diet and lack of exercise. Poor awareness may therefore be a key barrier to improving physical health in people with SMI rather than a lack of motivation per se
. In fact, our previous work has shown that people with SMI are willing to participate in cardiovascular screening programmes based in primary care, if invited to do so, with participation rates being similar to those from community-based populations [45
]. Moreover, a recent study evaluating an intervention targeted at increasing exercise in people with SMI revealed that people with SMI are keen to participate in these programmes provided that they are acceptable and carefully designed to meet the specific needs of this population group [46
It has long been well-established that people with depression and anxiety disorders [47
], as well as those with personality disorders [48
] demonstrate greater externality in their locus of control compared to non-psychiatric populations. However, our participants with SMI exhibited even greater external health locus of control than people with non-psychotic mental illness, as evidenced by the results of the "powerful others" and "chance" subscales of the MHLC. People with more chronic forms of psychosis have already been to shown to be more likely to report having less control over their mental illness and a more external locus of control than people with less chronic forms of SMI [49
]. A smaller study also showed that people with schizophrenia (n
= 22) have higher scores on external health locus of control measures compared with population norms [50
]. We are not aware of previous studies that have explored locus of control in people with SMI in relation to people with non-psychotic mental illness. This high external locus of control is likely to be a reflection of the patients' feelings that their illness may be outside their control given its occasional unpredictability, which may additionally extend to their perceived level of control over their physical health. Ultimately, it may also indicate that health professionals are in a good position of exerting a high level influence on people with SMI with regards to their physical health and this fact could be used advantageously when designing interventions directed to improve physical health. Greater awareness of this finding will also remind clinicians to work towards empowering their patients.
We were unable to determine the profile of those who declined to take part in the study. It is possible that those who did not participate preferred not to take part as a result of strong beliefs about their physical health or perhaps poor physical health and this could therefore have influenced our findings. However there is no reason to expect that this bias would apply differently to the two groups. We employed measures of overall health which are simple, have been used extensively and shown to have validity. However the questionnaires have not been specifically designed to be used amongst populations with mental illness. Overall there were enough participants in the study to give reliable results in the statistical analysis. However this study is likely to be underpowered with respect to results concerning motivation to change, which might limit the strength of these findings. Moreover, our study was based entirely on self-report measures, which limited the breadth and nature of data that could be collected, such as past psychiatric history, severity of illness and other clinical variables. Ideally, we should have also included a third group of participants from the general population as this would have made our findings even more robust. Nevertheless, our central objective was to explore whether people with SMI exhibit unique characteristics in their physical health behaviours and health locus of control compared with people with non-psychotic mental illness. Finally, it is also acknowledged that we addressed a wide range of questions, which may have precluded our study from having clear-cut and succinct objectives. However, this study was of a preliminary nature set against the prospect of addressing more tightly focused research questions in the near future, guided by the findings of the present study.
This study raises important issues concerning the physical health needs of people with SMI. It continues to emphasise the importance of focusing on lifestyle issues for people with SMI in order for them to engender change that decreases the burden on their physical health. Rather than lack of motivation being a key factor in affecting physical health it appears that lack of awareness and a lack of prioritisation are the main obstacles to improving physical health in this population group. Furthermore, people with SMI are more likely to express greater externality in health locus of control compared with people with non-psychotic mental illness. Clinicians could therefore exploit this finding to help address lifestyle and physical health needs of these patients. Interventions should also aim to increase the awareness of healthcare professionals about the physical health needs of people with SMI. Evidence does suggest that behavioural lifestyle interventions are more likely to be taken up by people with SMI when the support of healthcare professionals is available in these interventions [37
]. This will allow them to act more pro-actively in encouraging patients to participate in routine physical health assessments and prophylactic measures.