Adherence to anti-hypertensive medication: proposing and testing a conceptual model.

OBJECTIVES: A conceptual model of the psychological factors underpinning adherence to anti-hypertensive medication is proposed and tested. The model suggests that adherence is influenced by three sets of variables: demography, health status, and perceived effects of medication; cognitions and motivation; and intention to adhere. METHODS AND DESIGN: Patients with known hypertension were recruited from three primary care practices in South-East England and were asked to complete a postal questionnaire. A total of 1,070 responses were received. The questionnaire asked about the three sets of predictor variables, and adherence. Eight weeks after the first questionnaire, a second was posted to all respondents, this time asking about adherence over the intervening period. RESULTS: The three sets of predictor variables were treated as blocks in a hierarchical model, so that each successive block added to the variance in adherence explained by the previous blocks. The data were analysed by hierarchical multiple regression. The predictors accounted for 19% of the variance in adherence at Time 1, and 34% at Time 2. The leading individual predictors at Time 1 were age, gender, conscientiousness, hypertensive identity, perceived behavioural control, and intention. At Time 2, they were the same, except that gender made way for adherence at Time 1. CONCLUSIONS: The model offers a parsimonious account, and the findings suggest a number of approaches to designing interventions to modify behaviour.

Longitudinal analysis of the illness representation model in patients with irritable bowel syndrome (IBS).

A prospective longitudinal study explored the illness representation model of patients with irritable bowel syndrome: how representations may change; whether they predict subsequent psychological outcome; and whether any link between representation and outcome may be mediated by coping. Patients were recruited from primary care. Representations were found to be stable over time, and they did predict outcome to some extent, but coping played no part in mediating the link. The findings raise important questions about using the illness representation model with chronic illness, and about the role of coping in the model.

Illness representation, coping and outcome in irritable bowel syndrome (IBS).

OBJECTIVE: Irritable bowel syndrome has no observable symptom markers and there is little that the medical profession can do to help sufferers. Psychotherapy, antidepressants and drugs aimed at the most problematic symptoms have been shown to have limited efficacy. In an attempt to help understand the illness better, and to suggest alternative forms of intervention, the study tested whether outcome might be influenced by patients' representation of their illness and by their coping strategies. METHOD: All members of the IBS Network (an independent charitable support network based in the UK) were invited to participate via their quarterly newsletter, and 209 completed questionnaires were returned. Participants completed the Illness Perception Questionnaire (IPQ), the COPE, and the Hospital Anxiety and Depression Scale (HADS), and rated their quality of life and their satisfaction with their health. RESULTS: The reporting of serious consequences was associated with lower quality of life and lower satisfaction with health, and with higher scores for anxiety and depression (p <.001). Weaker control beliefs were related to lower quality of life, lower satisfaction with health, and higher depression scores (p <.01). Lower illness scores were associated with more satisfaction with health (p <.01), but not with quality of life (p >.05). Psychological causal attribution of IBS was positively correlated with anxiety (p <.001) and depression (p <.01). Path analyses based on multiple linear regression demonstrated that (1) the reporting of serious consequences was a strong independent predictor of outcome; (2) coping mediated the link between representation and outcome; and (3) when predicting depression, coping strategies predicted coping independently of representation dimensions. CONCLUSIONS: The findings indicate that the illness representations of IBS sufferers can have significant implications for outcome. Therapeutic interventions based on illness representations may prove useful for treatment.