Investigating the efficacy of cognitive bias modification for interpretation and the Maudsley Review Training Programme on social anxiety and reasoning biases in individuals with persecutory delusions: a single case series

The Threat Anticipation Model (Freeman, 2007) implicates social anxiety and reasoning biases in the formation and maintenance of persecutory delusions. Computerised packages, such as Cognitive Bias Modification for Interpretation (CBM-I) have been shown to improve social anxiety in psychosis (Turner et al., 2011). Similarly, the Maudsley Review Training Programme (MRTP) has improved reasoning biases associated with delusions (Waller et al.,2011). This study examined the use of both of these treatment packages in people with persecutory delusions. It was hypothesised that CBM-I would reduce social anxiety, but not reasoning biases and that the MRTP would reduce reasoning biases, but not social anxiety. It was also hypothesised that both packages would reduce paranoia. A single case series design with twelve participants from Early Intervention and Recovery services in Norfolk was used. Measures of social anxiety, paranoia and reasoning biases were taken during baseline, package and one-month follow up. Data were analysed according to Kazdin’s (2010) criteria and were inspected for clinical and reliable change. Complimentary analyses were also performed using Simulation Modeling Analysis (Borckardt, 2006) and inferential statistics. Results indicated mixed support for the first hypothesis and moderate support for all other study hypotheses. Paranoia reduced in line with reductions in social anxiety and/or reasoning biases in eight cases. In two cases, no improvement in social anxiety or reasoning biases corresponded with lack of improvement in paranoia. The remaining two cases contradicted any relationship between improved social anxiety, reasoning biases and paranoia. These findings support the Threat Anticipation Model (Freeman, 2007), suggesting that social anxiety and reasoning biases are distinct mechanisms in the formation of paranoia that have unique aetiology and treatment responses. Computerised therapy may help people who are unwilling to engage with services and reduce cost of provision