Exploration of the impact of adherent CPAP use on mood following the implementation phase.
The prevalence of affective disorders such as anxiety and depression in relation to the treatment adherence of chronic illnesses and diseases has received much attention over the past 50 years. While initially the focus of research was on chronic illnesses and diseases such as cancer, renal disease, rheumatoid arthritis, diabetes, coronary disease, and HIV (Dwight et al., 2000; Katon et al. 2001; Katon & Ciechanowski, 2002), researchers of sleep disorders have also paid attention to investigating the role that mood plays with regard to CPAP adherence (see Section 1.8.8: Table 10).
Generally, research has presented mixed findings on this topic, and the association between mood (particularly depression) and OSA has been deemed coincidental or perhaps the results of uncontrolled factors such as age, BMI, fatigue, and other co-morbidities (Reynolds et al., 1984; Millman et al., 1989; Engleman et al., 1994; Borak et al., 1996; Engleman et al., 1997; Engleman et al., 1998; Charbonneau et al., 1999; Munoz et al., 2000; Yamamoto et al., 2000; Means et al., 2003). The current study, however, extended its focus beyond examining only anxiety and depression to examine a range of moods measured by the POMS-SF. Overall, the findings demonstrated observable and statistically significant improvements in vigour/activity and fatigue/inertia after six months of CPAP use. Observable, but non- significant improvement in symptoms of tension/anxiety, depression/dejection, anger/hostility, confusion/bewilderment, and TMD following CPAP implementation in adherent patients were also noted.
Less that 21% of patients reported negative symptoms of tension/anxiety, depression/dejection, anger/hostility, confusion/bewilderment, and TMD at the
diagnostic phase. This suggests patients presented with minimal negative mood- related symptoms, which may account for the non-significant findings following the implementation phase. Yu et al. (1999) and Means et al. (2003) also reported similar findings for mood to those of the present study. In their study, Means and colleagues reported that approximately 35% of their sample reported depressive symptoms pre- CPAP use at diagnosis. This level is considered to be low and is akin to the figure of approximately 15% reported in the present study. Yu et al. also reported similar findings in their study, which investigated the effect of CPAP use on mood states by comparing results between a CPAP treatment and placebo group. In their study, Yu and colleagues excluded patients with major psychiatric illness, and therefore low scores on the POMS at pre-CPAP use were reported for both the treatment and placebo groups. Similar to the present study, Yu et al. reported improvement in mood post-CPAP use in both the treatment and placebo groups, but this was not statistically significant. Yu et al. attributed their findings to the placebo effect, the short CPAP use period (one week) and the relatively low initial scores on all POMS sub-scales. It is therefore likely that in the present study CPAP treatment would have had a more positive impact on mood in patients where their symptomatology was assessed as moderate to severe. In this study’s sample, mood scores following the
implementation phase were predominantly in the normal to mild range. It is likely that patients’ mood scores were not high enough initially to detect any statistically
significant improvements after six months of CPAP use on all of the POMS-SF sub- scales.
In this study, 78% of patients did however report negative symptoms associated with vigour/activity and 51% with fatigue/inertia at the diagnosis phase.
This finding that possibility suggests that energy levels and exhaustion were the key presenting symptoms in patients with moderate to severe OSA. These figures also suggest that change is more observable in patients that present with moderate to severe symptomatology. Such a finding corresponds with those of Derderian et al. (1988) and Kribbs et al. (1993), who were one of the first to utilise the POMS to measure positive changes in mood after a period of CPAP therapy. Derderian et al. reported improvement in depression/dejection and overall TMD, and Kribbs et al. reported improvement in vigour/activity post-CPAP use. Both studies also, reported significant improvement in fatigue/inertia as measured by the POMS. The current study mirrored the findings of Derderian et al. and Kribbs et al. and showed observable improvements in vigour-activity and fatigue/inertia following CPAP implementation at the six month mark. Further exploration using Paired Sample t-tests showed that symptoms of fatigue/inertia statistically significantly improved following the implementation phase with CPAP use. As previously noted, 51% of patients presented with fatigue at the diagnostic phase, which decreased to 26% following a six month period of CPAP use. Vigour/activity also yielded statistically significant results that showed an improvement in overall level of activity after six months of CPAP use. While there was an observed improvement in the percentage of patients who reported an improved overall TMD, the results of a Paired Sample t-test showed that this was not statistically significant. Nonetheless, such noticeable improvements may still play an important role in an individual’s improvement of health and quality of life.
Interestingly, while not statistically significant, there was also a notable increase in anger following the implementation phase with six months of CPAP use.
Although patients who reported increased levels of anger at the implementation phase were predominantly patients in the non-adherent group, a small proportion of adherent patients also reported a slight increase in anger. It is plausible that reasoning relating to OSA being symptomatic and not curative may account for the slight observable increase in anger scores within the adherent group as patients begin to realise the permanence of CPAP use (Munoz et al., 2000).