5. Limitations
depression, anxiety
EVENT
The present study is subject to some limitations that must be acknowledged. Firstly, the participants were recruited at urban public health centres, and their characteristics might differ from those of caregivers attending private health centres or residents of other geographical areas. Consequently, the generalisation of our results may be limited. Moreover, as there were more caregivers with higher CSI scores (>7) in the intervention group (61%) than in the control group (54%) at baseline, the findings should be interpreted with caution. However, these differences were slight and not statistically significant.The internal validity of the trial could be compromised if the participants in the control group guessed their placebo condition. In the event of failed blinding, a serious limitation to the internal validity of the trial would be presented due to the fact that patients' perception of treatment are related to their treatment responses in some situations. In order to minimise the Hawthorne effect, all participants were personally interviewed by a case management nurse to obtain the necessary sociodemographic information and explain the procedures involved (including instructions for both groups regarding the use of the audio listening device). In addition, the members of the intervention group were asked about their preferred style of music. This question was not asked of the control group in order to prevent them from realising they were not receiving the intervention. Nevertheless, this difference in the questions asked of the two groups and the consequent Hawthorne effect may be considered a limitation.Despite these limitations, the rigorous nature of the clinical trial conducted supports the validity of the conclusions drawn. Future research should elucidate the long-term effect of music listening on reducing caretaker burden, as well as its relation to other health outcomes such as quality of life, anxiety, and depression.