Psychological masquerade embedded in a cluster of related clinical errors: Real practice, real solutions, and their scientific underpinnings.

: In this paper, we discuss the need for medical rule outs in over 50% of DSM–5 diagnoses and the risk for mental health practitioners to engage in a clinical judgment error called psychological masquerade (Taylor, 2007). We use the specific example of thyroid dysfunction as a relevant rule out when a client presents with symptoms consistent with an affective disorder. A real clinical example is provided and discussed to illustrate how the first author invoked psychological masquerade resulting in clinical decision-making errors during the treatment of a mother participating in family therapy. Solutions for this specific case and more generally for psychological masquerade are provided and discussed in the context of theory and research on mental health clinical decision-making.