While there was no significant benefit on the primary outcome measure, depression, agitation levels decreased significantly over time with humour therapy compared with usual care with the mean adjusted change difference between baseline and follow-up being 2.52 points—this would be equivalent to two agitated behaviours decreasing in frequency from daily to once a week. Difference between treatment and control groups on change scores on the CMAI pooled across three randomised controlled trials of risperidone were 3. (95% CI 1.78 to 4.22).33
In decreasing agitation, humour therapy had a similar effect to risperidone, the most commonly used antipsychotic in Australia for the treatment of behavioural disturbance in dementia.34
Humour therapy showed none of the side effects of risperidone. When adjustments were made for the ‘dosage’ of humour therapy engagement, humour therapy demonstrated benefits on depression, behavioural disturbance and self-reported dementia quality-of-life effects not reported with medication.
The strengths of SMILE include: a large sample, clustered design and relatively high follow-up rates. We were able to implement our intervention in real-world nursing homes, despite initial reservations from some managers and staff. The sustained benefits in agitation at follow-up underscore the importance of recruiting staff members into the programme. Limitations are noted. First, data collection staff became ‘unblinded’ over time for 15 of the 35 homes despite constant reminders to nursing home staff ahead of data collection periods of the importance of maintaining confidentiality of intervention allocation. Second, participating homes might not have been representative of Australian nursing homes. Compared with national data, residents in our sample were similar in average age and dependency level, but were 6% more likely to be female, required less help with activities of daily living and had higher levels of behavioural disturbances. Third, there were variations between residents in the number of ElderClown sessions they received, and variations between homes in the amount of humour initiated by LaughterBosses outside ElderClown sessions. LaughterBosses were not tested for competency in delivering humour. Fourth, the two groups were unbalanced at baseline on several outcome measures, these differences were adjusted for in our statistical modelling. Fifth, adjustment for multiple comparisons was not made to the α for significance, as outcome measures were correlated. Sixth, the intracluster correlations for this sample were much higher than reported in the study on which our power calculations were based, which resulted in lower power than planned.
Several explanations are possible for the lack of effect on outcome measures other than CMAI agitation. Depression, other forms of behavioural disturbances and self-rated quality-of-life all improved more in residents who experienced higher doses of engagement as a result of humour therapy, suggesting that humour therapy does change these outcomes, even though there was not a statistical advantage of intervention over control groups. There was a floor effect: only 29% of our sample was assessed as having probable or possible depression on the CSDD, and 28% of our sample was rated as not having any agitation symptoms on the CMAI, thereby limiting the potential for improvement. The DEMQOL was developed for persons with mild to severe dementia; however, 33% of residents were unable to complete the self-report version. While we interviewed staff members who knew the resident well, it was difficult for staff to be aware of the quality-of-life related concerns of many residents, particularly those with poor verbal skills. Our data and others showed that DEMQOL proxy scores correlate only mildly or moderately with DEMQOL self-report. The measures used might not have been sensitive to anecdotally reported positive effects such as increased positive mood, and increased initiation of and participation in social activities.
We offered a novel model of humour therapy delivery combining staff training (LaughterBosses) and professional humour therapists (ElderClowns). This was designed to minimise costs and deliver sustainable practice change within nursing homes. We believe that the active ingredients of the programme are engagement and play. This is supported by our engagement dose analyses and consistent with a needs-driven behaviour explanatory model of behaviours.35
Increasing social contact and opportunities for play could have fulfilled a need for stimulation which is expressed through agitation. Other tailored models of engaging and stimulating residents might also be successful.36
Challenges in delivering the programme predominantly related to false expectations that, rather than attempting to elicit individual responses from residents enrolled in the study, the ElderClown would perform for any audience. Some suggest that the label ‘ElderClown’ might not be appropriate in describing the work of the professional performers.
SMILE demonstrated that there are benefits to increasing positive interactions for residents. If our results are replicated, consideration should be given to systematically introducing humour therapy as a psychosocial intervention to reduce the level of agitation in nursing home residents. More research is needed into the efficacy of different models of delivering humour therapy.