Christopher R. Martell, PhD, ABPP, is the Director of the Psychological Services Center at the University of Massachusetts Amherst, where he is also a Lecturer. He maintained an independent practice for 23 years, providing cognitive-behavioral therapy to clients with mood and anxiety disorders. Dr. Martell conducts workshops and trainings on behavioral activation (BA) nationally and internationally and has consulted on research teams examining BA around the world. His books include Behavioral Activation for Depression: A Clinician's Guide (coauthored with Sona Dimidjian and Ruth Herman-Dunn). He is a recipient of honors including the Distinguished Psychologist Award from the Washington State Psychological Association.

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Steven A. Safren, PhD, is Assistant Professor of Psychology at Harvard Medical School, Associate Director of the Cognitive-Behavioral Therapy Program at Massachusetts General Hospital, and a research scientist at Fenway Community Health. He has published on LGBT mental health, behavioral aspects of HIV, and mood and anxiety disorders. Dr. Safren is the Principal Investigator of an NIMH-funded study of CBT for depression and HIV medication adherence.

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Stacey E. Prince, PhD, is in private practice in Seattle and is a Clinical Instructor at the University of Washington. Dr. Prince recently served as co-chair of the Washington State Psychological Association's Committee on LGBT Concerns. She has been involved in several NIMH-funded studies, and has published on gender issues in depression, CBT for depression, and integrative behavioral couple therapy.