Epigenetic perspective on behavior development, personality, and personality disorders.

After 30 years of clinical work and research based on categorical criteria for personality disorders (Diagnostic and Statistical manual of Mental Disorders - DSM IV TR) and (International Classification of Diseases - ICD 10th revision), a solid conceptual understanding and treatment of these disorders have not been established. For the field to move forward, it is imperative that future classifications introduce major revisions of the concept, diagnosis, and classification of personality disorders. This paper proposes one such revision. Based on recent advances in molecular biology and epigenetics, we define personality disorders as maladaptive syndromes developed trough person-environment interaction. We conceptualize maladaptation as a failure of integrative functions of personality (i.e., those that carry out adaptive processes) caused by strong biogenetic dispositions or by pathological environmental effects, or both. Hence, accurate diagnosis of personality disorder depends upon neurobiological (innate) and adaptive (interactive) etiological factors. We propose a 2-step diagnostic algorithm for personality disorders: adaptive processes (i.e., character) are used to diagnose maladaptation, whereas biological aspects (i.e., temperament) are used to specify dominant clinical presentation and for differential diagnosis. We suggest that the term "Personality Disorder" be replaced by a more appropriate term "Adaptation Disorder" as the latter reflects more accurately the real nature of the disorder and distributes the causality of maladaptive syndromes more evenly, between the person and the environment. Diagnostic, research, and treatment advantages of the proposed solution are discussed in some detail.