Type of symptomatology as a form of volunteer bias.
A. Convit, S. Levine, S. Berns and C. Evangelista,
Bull. Amer. Acad. Psychiatry & the Law
19(2): 185-91, 1991.
We sought to explore the relationship between type of psychopathology and consent bias. Using the
Brief Psychiatric Rating Scale we assessed a group of 48 forensic psychiatric inpatients. These
patients were later independently approached by a researcher who attempted to get their consent for
a study on the validity of self-reported criminal behavior. Thirty agreed to participate and 18 did not.
The consenting patients were significantly younger and had significantly more negative symptoms
than the nonconsenters. The difference in negative symptoms remained significant after age and
medication dose, in chlorpromazine equivalents, were covaried out. The authors discuss the
implications of these findings for forensic research.