Face-emotion processing in offspring at risk for panic disorder.
The acquaintanceship procedure is a method for obtaining a control group matched to relatives of probands on demographic variables. Relatives are asked to name six acquaintances who are the same gender, and who are about the same age and social class as themselves. An acquaintance is randomly selected from this list and contacted for recruitment. Rates of mental disorder in this group are assumed to approximate general population rates in a group with these demographic characteristics. This report focuses on an extension of the acquaintanceship procedure in which "super-normal" controls are used in a family study design. Two questions were addressed: (1) Does the acquaintance group (n = 166), as a whole, show a higher rate of illness than the relatives of acquaintances with no mental disorder (n = 129)? (2) Is there a relationship between mental disorder in acquaintances and in providers of acquaintance names? The prevalence of mental illness was significantly greater among acquaintances compared to relatives of "never ill" acquaintances. There was no evidence of assortative selection. We concluded that using the relatives of well acquaintances is a cost-effective control selection methodology which maximizes the detection of intergenerational transmission in family studies of mental disorder.