Psychopathology among persons responding to participation as normal controls in behavioral research studies

This study examined the characteristics of persons responding to an advertisement to participate as normal controls in behavioral research studies. Applicants (N = 3,289) inquired by telephone for more information. Of the applicants responding by telephone, 18% met the criteria for a DSM-III-R diagnosis, including psychoactive substance abuse (9%), mood disorder (4%), personality disorder (3%), schizophrenia (1%), anxiety disorder (1%), and neurological disorder (16%). Thirty-two percent (n = 1,045) of individuals passing the telephone interview were evaluated in person. After in-person evaluation, 16% met the criteria for a DSM-III-R diagnosis, including psychoactive substance abuse (9%), mood disorder (3%), personality disorder (3%), schizophrenia (0.1%), anxiety disorder (1%), and neurological disorder (11%). Only 13% (n = 431) of individuals responding by telephone were included as normal controls in ongoing studies. Overall, 79% (n = 2,244) and 57% (n = 590) were excluded by telephone and in-person evaluation, respectively. These results suggest that a high percentage of individuals seeking to participate as normal controls in behavioral research studies have some psychopathology.