Positive memory training for the treatment of depression in schizophrenia: A randomised controlled trial.

BACKGROUND: Around half of people diagnosed with schizophrenia suffer from co-morbid depression, yet there are no evidence-based psychological treatments to target this presentation. METHOD: Participants were aged 18-65 years old, had a clinical diagnosis of schizophrenia or schizoaffective disorder and at least a mild level of depression. Participants were randomly assigned (1:1) to receive PoMeT or treatment as usual. PoMeT was delivered in up to 12 individual sessions within 3 months. We stratified randomisation by site and by severity of depression using randomised-permuted blocks. Assessments were carried out at baseline, 3-month, 6-month and 9-month by assessors who were blind to treatment allocation. The primary outcome was reduction in the symptoms of depression at 3-month, 6-month and 9-month as measured by the BDI-II. Analysis was by intention-to-treat with linear mixed-effects models. The trial was registered with the ISRCTN registry number 99485756. RESULTS: One hundred participants were randomly assigned to either PoMeT (n = 49) or treatment as usual (n = 51). The reduction in BDI-II total score at 3 months was significantly greater for PoMeT than for treatment as usual (mean difference = 4.33, SE = 2.00, 95% CI 0.38 to 8.23; p = 0.03). DISCUSSION: To our knowledge this is, to date, the largest powered randomised controlled trial focused on the psychological treatment of depression in people diagnosed with schizophrenia. Results indicate that a brief targeted intervention can reduce the symptoms of depression in the group. The main limitation of the study is the lack of an active control group which may contribute to an inflated treatment effect.

Comparing correlations of continuous observations from two independent populations using a sequential approach.

A sequential study design generally makes more efficient use of available information than a fixed sample counterpart of equal power. This feature is gradually being exploited by researchers in genetic and epidemiological investigations that utilize banked biological resources and in studies where time, cost and ethics are prominent considerations. Recent work in this area has focussed on the sequential analysis of matched case-control studies with a dichotomous trait. In this paper, we extend the sequential approach to a comparison of the associations within two independent groups of paired continuous observations. Such a comparison is particularly relevant in familial studies of phenotypic correlation using twins. We develop a sequential twin method based on the intraclass correlation and show that use of sequential methodology can lead to a substantial reduction in the number of observations without compromising the study error rates. Additionally, our approach permits straightforward allowance for other explanatory factors in the analysis. We illustrate our method in a sequential heritability study of dysplasia that allows for the effect of body mass index and compares monozygotes with pairs of singleton sisters.