Background. Increasingly, evaluations of mental health
services include an economic component,
although often only summary statistics such as the mean or median
are reported. Measures of
variation are often limited to the standard error or standard deviation,
though costs are rarely
normally distributed and vary substantially between patients. The
aim of this study is to identify
factors that can explain variations in the cost of mental health
services for epidemiologically representative cases of psychosis.
Methods. Cases with ICD-10 diagnoses of functional
psychosis were drawn from a sample that
included all identified cases of psychosis in two geographically
defined sectors in Camberwell, south
London. Mental health service use was measured and costed. A
predictive model was developed
using multiple regression analyses, in which patient characteristics
and previous service use
indicators were used as predictor variables. Services were measured
using the Client Service Receipt Interview.
Results. Among the 147 cases included, the amount of cost
variation explained by the model was
31·5%. The most significant predictive factor was social
functioning, which was highly negatively associated with cost.
Conclusions. Current mental health service use can be
predicted to a reasonable extent by previous
service use and patient characteristics, especially the degree of
social disability. Identification of such
factors can aid the effective allocation of scarce resources. In
particular, subgroups of patients who
use most resources can be identified and targeted by mental health services.