Screening and genetic counseling for beta-thalassemia trait in a population unselected for interest: effects on knowledge and mood.

To evaluate the effects of genetic screening and counseling in a population unselected for interest, adults in a health maintenance organization (HMO) were screened for beta-thalassemia trait as part of health care or multiphasic screening. Counseling was provided by either a trained physician or a videotape containing the same information, followed by an opportunity to question a trained physician. Knowledge of thalassemia, knowledge of genetics, and mood were assessed by standardized questionnaires and by interview immediately before and after counseling. Compared to controls, trait subjects demonstrated significant learning about thalassemia (P less than .001) and about genetics (P less than .001) and recorded significant mood changes, namely, surprise (startle) (P less than .05), increased alertness (decreased deactivation) (P less than .05), and decreased skepticism (P less than .01). Screening and genetic counseling for beta-thalassemia trait conducted as part of multiphasic screening of the population of a HMO, essentially and unselected population, can result in significant overall learning with acceptable effects on mood.