19Use of the Manual
The introduction  contains much of the history and developmental process of the
DSM-5 revision. This section is designed to prov ide a practical guide to using DSM-5, par-
ticularly in clinical practice. The primary purp ose of DSM-5 is to assist trained clinicians
in the diagnosis of their patients’ mental diso rders as part of a case formulation assess-
ment that leads to a fully informed treatmen t plan for each individual. The symptoms con-
tained in the respective diagnostic criter ia sets do not constitute comprehensive
definitions of underlying disorders, which encompass cognitive, emotional, behavioral,
and physiological processes that are far more co mplex than can be described in these brief
summaries. Rather, they are intended to summa rize characteristic syndromes of signs and
symptoms that point to an underlying disord er with a characteristic developmental his-
tory, biological and environmental risk factors, neuropsychological and physiological cor-
relates, and typical clinical course.
Approach to Clinical Case Formulation
The case formulation for any given patient must  involve a careful clinical history and con-
cise summary of the social, psychological, and biological factors that may have contrib-
uted to developing a given mental disorder. Hence, it is not sufficient to simply check off
the symptoms in the diag nostic criteria to make a mental  disorder diagnosis. Although a
systematic check for the presence of these crit eria as they apply to each patient will assure
a more reliable assessment, the relative severity and valence of in dividual criteria and
their contribution to a diagnosis require clin ical judgment. The symptoms in our diagnos-
tic criteria are part of the relatively limited repertoire of human emotional responses to in-
ternal and external stresses that are genera lly maintained in a homeostatic balance without