Introduction

It has been suggested that psychological stress may be related to asthma morbidity and furthermore that depression significantly affects adherence behaviour in asthmatic patients (Cluley and Cochrane, 2001). The aim of the present study was to examine the influence that anxiety and depression have on current (AC1) and future (AC2) asthma control in patients with difficult to control asthma.

Methods

At their first visit to a hospital outpatient clinic, 58 patients with difficult to control asthma completed a hospital anxiety and depression questionnaire (Zigmond et al., 1983) and an asthma control questionnaire (ACQ; Juniper et al., 2001). They were seen by a hospital physician who optimised their asthma medication as required. At their second visit, 9±6.2 months later, the patients completed the ACQ for a second time.

Results

At the initial visit, anxiety (r=0.27, p=0.04) and depression (r=0.40, p=0.002) were significantly correlated with AC1. At the follow up visit AC2 was still significantly correlated with both anxiety (r=0.44, p<0.0001) and depression (r=0.4, p<0.002) as measured at visit one.

Multiple regression analysis confirmed that anxiety and depression were associated with poor current asthma control (AC1; p=0.008). The proportion of variability (R²) explained by the later variables was 16%. A further regression indicated that AC1 accounted for a significant amount of the variability in AC2 (p<0.0001). The proportion of variability (R²) explained by previous asthma control was 23%.

A final multiple regression analysis, which examined AC2 as the dependent variable and AC1, anxiety and depression as the predictors, indicated that anxiety and depression accounted for a significant proportion of the variance in AC2 after controlling for the effects of AC1 [R² change = 0.1 (10% above the effect of AC1; p=0.02]. This confirmed that anxiety and/or depression contributed significantly to future asthma control in the study patients, possibly through poor adherence with prescribed medication.

Discussion

In previous study (Cluley et al., 2001) it was found that those patients in whom asthma was well controlled had significantly less psychiatric morbidity (anxiety and depression) when compared with those with poorly controlled asthma. The results of the present study indicate that anxiety and depression are not only significantly correlated with current asthma control but also with future control. The results suggest that active interventions to improve anxiety and depression in patients with poorly controlled asthma is required, in addition to optimising prescribed asthma mediation, if good future asthma control is to be achieved.

References

1 Cluley S. and Cochrane G. (2001) Psychological disorder in asthma is associated with poor control and poor adherence to inhaled steroids. Respiratory Medicine 95; 37-39.

2 Juniper E., O'Byrne P., Roberts J. (2001) Measuring asthma control in group studies. Respiratory Medicine 95: 319-323.

3 Zigmond A. and Snaith R. (1983) Hospital anxiety and depression scale. Acta Psychiatrica Scandinavica 67: 361-370.