Symptom validity in clinical assessments

Psychological tests may help healthcare professionals make the right diagnosis and give adequate treatment advice. Patients taking a test are expected to do their best and fill in questionnaires honestly and accurately. However, it turns out that this may not always the case. The validity of self-reported symptoms and performance in cognitive tests is defined as symptom validity. This dissertation shows that symptom validity is insufficient in a substantial minority of psychological tests. As a result, these tests may not provide reliable diagnostic information about a patient. An important clinical implication is that symptom validity should always be measured when performing psychological evaluations.