Use of the Manual 21
Criterion for Clinical Significance
There have been substantial e fforts by the DSM-5 Task Force and the World Health Orga-
nization (WHO) to separate the concepts of mental disorder  and disability (impairment in
social, occupational, or other important areas of functioning). In the WHO system, the In-
ternational Classification of Diseases (ICD) c overs all diseases and disorders, while the In-
ternational Classification of Functioning, Disability and Health (ICF) provides a separate
classification of global disability. The WHO Disability Assessment Schedule (WHODAS)
is based on the ICF and has proven useful as a standardized measure of disability for men-
tal disorders. However, in the absence of clea r biological markers or clinically useful mea-
surements of severity for many mental disord ers, it has not been possible to completely
separate normal and pathological symptom expressions contained in diagnostic criteria.
This gap in information is particularly problematic in clinical situations in which the pa-
tient’s symptom presentation by itself (particu larly in mild forms) is not inherently path-
ological and may be encountered in individuals for whom a diagnosis of “mental
disorder” would be inappropriat e. Therefore, a generic diagno stic criterion requiring dis-
tress or disability has been used to establish disorder thresholds, usually worded “the dis-
turbance causes clinically significant distre ss or impairment in social, occupational, or
other important areas of functioning.” The text  following the revised definition of a mental
disorder acknowledges that this criterion may be especially helpful in determining a pa-
tient’s need for treatment. Use of informatio n from family members and other third parties
(in addition to the individual) regarding the individual’s perf ormance is recommended
when necessary.
Elements of a Diagnosis