write:B. Yeats (“Among School Children ” 1928)Psychiatric classifications systems like the Diagnostic and Statistical Manual of Mental Disorders (DSM; Amer-ican Psychiatric Associati

great rooted blossomerAre you the leaf
the blossom or the bole?—W. B. Yeats (“Among School Children
” 1928)Psychiatric classifications systems like the Diagnostic and Statistical Manual of Mental Disorders (DSM; Amer-ican Psychiatric Association
2013) or the International Statistical Classification of Diseases (ICD; World Health Organization
2019) categorize mental health problems into diagnoses such as schizophrenia and posttraumatic stress disorder (PTSD). These diagnoses are further described by criteria
often specific symptoms. The his-tory of defining the diagnosis for major depressive dis-order (MDD) helps to clarify the crucial distinction between mental health problems and diagnoses by which they are classified.DSM’s fifth edition (DSM-5) specifies that an episode of MDD can be diagnosed if a person meets at least five of nine symptoms for 2 weeks and also shows considerable impairment of functioning. What data jus-tify these particular criteria? In an effort to introduce the medical model to psychiatry
Feighner et al. (1972) delineated what have come to be called the Feighner criteria: observable signs and symptoms for common mental disorders. For determining the symptoms of MDD
the authors relied on a 1957 article by Cassidy and colleagues. The Feighner criteria were highly influ-ential for DSM-3
and today
all MDD symptoms pro-posed originally by Cassidy
with one exception (constipation)
are preserved in DSM-5
with a similar threshold for clinical significance (DSM-5: at least five of 9 symptoms; Cassidy: at least six of 10 symptoms). When Cassidy was asked in 1980 about his reasoning behind these criteria
he responded that “it sounded about right” (Kendler et al.
2010
p. 136).1114089CDPXXX10.1177/09637214221114089FriedCurrent Directions in Psychological Scienceresearch-article2022Corresponding Author:Eiko I. Fried
Department of Clinical Psychology
Leiden University Email: eikofried@gmail.comStudying Mental Health Problems as Systems
Not SyndromesEiko I. FriedDepartment of Clinical Psychology
Leiden UniversityAbstractDespite decades of clinical
sociopolitical
and research efforts
progress in understanding and treating mental health problems remains disappointing. I discuss two barriers that have contributed to a problematic oversimplification of mental illness. The first is diagnostic literalism
mistaking mental health problems (complex within-person processes) for the diagnoses by which they are classified (clinically useful idealizations to facilitate treatment selection and prognosis). The second is reductionism
the isolated study of individual elements of mental disorders. I propose conceptualizing people’s mental health states as outcomes emerging from complex systems of biological
psychological
and social elements and show that this systems perspective explains many robust phenomena
including variability within diagnoses
comorbidity among diagnoses
and transdiagnostic risk factors. It helps us understand diagnoses and reductionism as useful epistemological tools for describing the world
rather than ontological convictions about how the world is. It provides new lenses through which to study mental illness (e.g.
attractor states
phase transitions)
and new levers to treat them (e.g.
early warning signals
novel treatment targets). Embracing the complexity of mental health problems requires opening our ivory towers to theories and methods from other fields with rich traditions
including network and systems sciences.Keywordsbiological reductionism
complex systems
diagnostic literalism
emergence
mental disorders
psychiatric nosology
reductionism