It is argued that researchers' reliance on “objective” mental health scales and disregard for clinical judgment has led to many mistaken conclusions. Specifically, standard mental health scales appear unable to distinguish between genuine mental health and the facade or illusion of mental health created by psychological defenses. Evidence is presented indicating that (a) many people who look healthy on standard mental health scales are not psychologically health, and (b) illusory mental health (based on defensive denial of distress) has physiological costs and may be a risk factor for medical illness. Clinical judges could distinguish genuine from illusory mental health, whereas “objective” mental health scales could not. The findings call into question the conclusions of many previous studies that rest on standard mental health scales. They suggest new ways of understanding how psychological factors may influence health. Finally, they suggest that clinical methods (which researchers often malign) may have an important role to play in meaningful mental health research.