Diagnoses of major depression, post-traumatic stress disorder, generalized anxiety disorder, and mild brain injury are based in substantial part on the self-reported symptoms of patients. This study found that 96.9% of untrained subjects were able to endorse symptoms on checklists to meet the DSM-III-R self-report criteria for major depression, 96.9% for generalized anxiety disorder, and 86% for PTSD. For the non-DSM-III-R diagnosis of mild brain injury, 63.3% of subjects were able to correctly identify 5 or more of 10 symptoms associated with this condition. Forensic examiners are advised to exercise special care in utilizing evaluation procedures that are of a leading nature, such as symptom checklists in which examinees may exhibit response biases.