title: Volunteer and nonvolunteer characteristics in an outpatient population.
mesh_terms: D001294:Attitude to Health; D004532:Ego; D005260:Female; D006801:Humans; D008950:MMPI; D008297:Male; D009042:Motivation; D009497:Neurotic Disorders; D010044:Outpatient Clinics, Hospital; D010554:Personality Disorders; D012559:Schizophrenia