MACH Trial

Treatment of Child Anxiety Disorder in the context of Maternal Anxiety: a randomised controlled trial

Anxiety disorders are the most common form of psychopathology in children. They have a significant adverse impact on children’s general socio-emotional functioning and commonly persist into adulthood. Following advances in the development of successful cognitive behavioural therapies (CBT) for adult anxiety disorders, CBT for child anxiety disorders has now been developed. Although there is still some uncertainty over the optimal form of such intervention, recent systematic reviews of outcome research indicate that the general CBT approach produces significant therapeutic benefit in this patient group. However, it is clear from these reviews, and from the individual treatment trials, that outcome is highly variable, with a significant proportion of patients retaining their anxiety diagnoses following treatment (i.e. 16-61%). There has been little research into the factors that predict response to CBT in anxious children, although, in addition to severity of child anxiety, two factors are likely to be especially significant: anxiety in the mother, and the quality of the mother-child relationship.

In an RCT for child anxiety occurring in the context of maternal anxiety, the principal questions are:
i. Is the impact of child CBT (CCBT) enhanced by first providing CBT to the mother for her own anxiety?
ii. Is the impact of CCBT enhanced by the addition of therapeutic measures designed to improve the quality of the mother-child relationship?

Secondary questions are:
i. Is sustained improvement in child anxiety significantly associated with a reduction in maternal anxiety?
ii. Is sustained improvement in child anxiety significantly associated with improvements in maternal modelling, encouragement, over-controlling/over-protective behaviour, and associated cognitions?

The outcome from CBT for children with anxiety disorders is highly variable. Major factors contributing to this are likely to be the presence of maternal anxiety and associated disturbances in the mother-child relationship and maternal behaviours. Where parental anxiety has been addressed in treatment research , for several methodological reasons, it has been difficult to assess  its contribution to child outcome. It is notable, however, that in the single study in which treatment of parental anxiety was systematically varied, child anxiety outcome was better where therapeutic measures to address parental anxiety symptoms were included. Whilst this is a finding of critical importance, since the treatment did not significantly alter levels of parental anxiety it remains unclear what aspect of the treatment effected the clinical improvement in the children. Similarly, where therapeutic measures to improve the parent-child relationship have been included, it has not been possible to determine the specific role of such measures in the complex treatment package employed. A controlled trial in which both treatment of maternal anxiety and measures to improve the quality of the mother-child relationship are systematically examined, would produce data of both clinical utility and scientific importance.

An economic evaluation will be undertaken integral to the main trial. The economic analysis will estimate the incremental cost and effectiveness of each of the CBT configurations. Patient level resource use data, including all health and social care costs (staff costs for provision of the interventions, and placebo interventions, GP costs, referrals, and other relevant services identified) as well as leisure and productivity estimates for the parents will be collected within trial forms and valued using appropriate unit costs. Staff training costs and the costs of staff supervision will also be identified and allocated pro-rata.  In line with recommendations from the National Institute for Health and Clinical Excellence (NICE) the economic evaluation will include a generic quality of life instrument, the child friendly EuroQol EQ-5D.. This  instrument will be administered at baseline, following treatment and at 6 months follow up.

Consideration of the distribution of the cost and effect data will be given in the  economic analysis. In order to explore the variation around the costs and effects generated by the trial data stochastic variance around the cost-effect pairs will be estimated using non-parametric bootstrapping methods. The incremental cost and the incremental benefits (utility) will be reported within an incremental cost-effectiveness ratio (ICER) format where appropriate. The results for the cost-effectiveness analysis  will be expressed in terms of positioning on the cost-effectiveness plane as well as translated into cost-effectiveness acceptability curves, indicating the likelihood that that the results fall below any given cost-effectiveness ceiling ratio (Rc).

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