The Research Committee of the Group for Advancement of Psychiatry (GAP), a specialty think-tank, has addressed psychiatry's need for a unifying scientific foundation. Such a foundation would consider the disorders commonly treated by psychiatrists in terms of the physiological baseline from which they depart, much as heart disease is understood as deviation from normal cardiac function. The relevant physiological focus for psychiatry is the social brain.

The social brain concept focuses on the interaction between brain physiology and the individual's environment. The brain is the organ most influenced on the cellular level by social factors across development; in turn, the expression of brain function determines and structures an individual's personal and social experience. The social brain framework may have greater direct impact on the understanding of some psychiatric disorders than others. However, it helps organize and explain all psychopathology. A single gene-based disorder like Huntington disease is expressed to a large extent as social dysfunction. 

Conversely, traumatic stress has structural impact on the brain as does the socially interactive process of psychotherapy. Brains, including human brains, derive from ancient adaptations to diverse environments and are themselves repositories of phylogenetic adaptations. In addition, individual experiences shape the brain through epigenesis, i.e., the expression of genes is shaped by environmental influences. Thus, the social brain is also a repository of individual development. On an ongoing basis, the brain is further refined through social interactions; plastic changes continue through life with both physiological and anatomical modifications.

In contrast to the conventional biopsychosocial model, the social brain formulation emphasizes that all psychological and social factors are biological in the broad sense of the term. Non-biological and non-social psychiatry cannot exist. Molecular and cellular sciences offer fresh and exciting contributions to such a framework but provide limited explanations for the social facets of individual function.

The social brain formulation is consistent with current research and clinical data. Moreover, it ultimately must:

• unify the biological, psychological and social factors in psychiatric illness,
  
• dissect components of illness into meaningful functional subsets that deviate in definable ways from normal physiology,
  
• improve diagnostic validity by generating testable clinical formulations from brain-based social processes,
  
• guide psychiatric research and treatment,
  
• provide an improved language for treating patients as well as educating trainees, patients, their families and the public, and
  
• account for the role of interpersonal relationships for brain function and health.

In conclusion, the concept of the brain as an organ that manages social life provides significant power for psychiatry's basic science. Burgeoning developments in neural and genetic areas put added demands on the conceptual structures of psychiatry.

Findings from such incoming work must be juxtaposed and correlated with the behavioral and experiential facets of psychiatry to give it a complete and rational basis. Psychiatry's full and unified entry into the realm of theory-driven and data-based medical science has been overdue. The social brain concept allows psychiatry to utilize pathogenesis in a manner parallel to practice in other specialties.

ACKNOWLEDGMENTS
This statement was composed by the listed members of the Research Committee of the Group for the Advancement of Psychiatry (GAP) during the periodic meetings of this group. The opinions expressed are those of the authors and do not represent an official opinion of GAP.