Psychology has been remarkably successful as a scientific discipline and field of clinical practice. Despite its remarkable growth, however, the field has also experienced substantial conflict and controversy. There has been great diversity in the approaches counselors and psychologists have used to understand development, psychopathology, and the goals and processes of psychotherapy. This has led to large numbers of conflicts and controversies that have distracted the field from its primary purposes. A biopsychosocial approach has the potential to bring the field together around a unified science-based framework for understanding mental health practice that will avoid these conflicts.