Mental well-being and mental distress

Mental disorders are characterised by psychopathology, distress and impaired functioning. Huppert ^{Reference Huppert3} and others argued that mental disorders (‘languishing’) and mental well-being (‘flourishing’) were opposite ends of a single dimension. However, further work has shown that, although correlated, mental illness and mental well-being are independent phenomena. Secondary analysis of data on over 7000 adults from the 2007 Adult Psychiatric Morbidity Survey (APMS) demonstrated that associations with well-being scores were not significantly altered by adjusting for comorbid mental disorder. ^{Reference Weich, Brugha, King, McManus, Bebbington and Jenkins4} These findings were consistent with those from other studies that indicate that mental well-being is more than just the absence of mental illness symptoms and distress, and that (although correlated) mental well-being and mental distress are independent of one another. The APMS findings also showed that at least moderately high levels of well-being may be achieved in the context of mental illness, which is salient when considering whether mental well-being should be a routine outcome measure in mental health services. ^{Reference Weich, Brugha, King, McManus, Bebbington and Jenkins4} Evidence detailed later in this editorial also supports this conclusion. However, we know less about the determinants and variability of mental well-being among those who experience mental health problems than in the general population. As mental illnesses typically relapse and remit, mental well-being may vary with the phase of illness and the number, frequency or duration of relapses.

Measuring mental well-being in people with mental illness

Evaluating interventions to improve mental well-being in people with mental illness depends on valid measurement, but there is only limited evidence to guide the assessment of mental well-being in this context. ^{Reference Davies2} This is a significant barrier to studying mental well-being and its potential determinants in people with mental illness. ^{Reference Davies2} Since mental well-being is a state of positive mental health, measures should comprise positively phrased items, such as those which make up the Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS), ^{Reference Tennant, Hiller, Fishwick, Platt, Joseph and Weich5} WHO-Five Well-Being Index (WHO-5) ^{Reference Bech, Olsen, Kjoller and Rasmussen6} and the Satisfaction with Life Scale. ^{Reference Kobau, Sniezek, Zack, Lucas and Burns7}

Although generic measures of mental well-being have been used for people with mental illness, their validity in these populations has rarely been evaluated; we do not know whether responses to generic mental well-being items may be biased by the experience of past or current mental illness. Only the WHO-5 has been validated in English in mental illness, specifically in affective and anxiety disorders. ^{Reference Newnham, Hooke and Page8} The Subjective Well-being under Neuroleptic Treatment Scale (SWN) ^{Reference Vothknecht, Meijer, Zwinderman, Kikkert, Dekker and van Beveren9} was developed for people with schizophrenia receiving antipsychotics. However, one-half of this scale comprises negatively worded items and it covers domains that are not central to mental well-being, including physical functioning. WEMWBS, despite being recommended by healthcare organisations for measuring mental well-being in the context of mental illness, has only been validated in non-clinical populations in the UK.

Mental well-being and mental health services

The 2011 UK government document No Health without Mental Health emphasised mental well-being as an important service outcome as part of patient-centred, recovery-focused care. ¹⁰ However, judging services according to mental well-being outcomes rather than changes in symptoms and disability is not self-evidently consistent with their traditional mission: the consequences of doing so need to be considered carefully. Measuring mental well-being routinely may alter therapeutic relationships in unintended ways. There is a risk that in prioritising mental well-being, professionals might be excused from achieving more challenging outcomes, namely alleviating symptoms and reducing disability. ^{Reference Davies2}

We would argue that two conditions must be met to justify the routine assessment of mental well-being among mental health service users. First, evidence is needed that mental well-being modifies the risk of onset, recovery from or recurrence of episodes of mental illness; in other words that it has prognostic significance in terms of mental health, social functioning or use of healthcare. Second, it must be shown that mental well-being is independent of mental illness and social functioning and therefore unlikely to be captured by measures that assess either of these phenomena.

Mental well-being and mental illness

Although the behavioural and psychosocial determinants of mental well-being may not necessarily resemble those of mental illness, mental well-being is associated with specific forms of psychopathology – examples are discussed below. However, the evidence base is generally limited by substantial methodological variation (including the use of different and often unvalidated measures of mental well-being) and a dearth of longitudinal studies, inhibiting understanding of cause and effect. ^{Reference Davies2}

Should mental well-being be used to support the commissioning and delivery of mental health services?

Valid methods of evaluating healthcare interventions are required to support payment by results, and National Health Service providers are required to collect patient-reported outcomes and experiences in part to prevent ‘gaming’ to maximise income. Mental well-being could serve as a patient-rated outcome measure, but the dearth of validated measures in people with serious mental illness remains a major concern. The CMO has sensibly encouraged policy makers and commissioners to heed the uncertainty surrounding mental well-being, warning that ‘wellbeing policy is running ahead of the evidence’. ^{Reference Davies2} However, existing evidence suggests that symptomatic and functional outcomes, needs for care and service use appear to be independent of mental well-being to varying degrees. Therefore, mental well-being is not captured completely by existing measures of these states. Mental well-being also has strong conceptual resonances with recovery from mental illness, including notions of hope, purpose and fulfilment, and may be similarly valued by patients. Taken together, these could represent significant arguments for mental well-being as a distinct service outcome in its own right. However, the utility of measuring mental well-being routinely in mental health services has not yet been established. Further research is needed to validate measures of mental well-being in people with serious mental illness, determine the usefulness (and costs) of routinely measuring mental well-being in this population, and to explore the views of patients on the relative importance attached to different service outcomes.