The Schedules for Clinical Assessment in Neuropsychiatry
The Schedules for Clinical Assessment in Neuropsychiatry. Version 2
Wing JK, chief editor
Geneva: World Health Organization—Division of Mental Health; 1994.331 p.
The Schedules for Clinical Assessment in Neuropsychiatry (SCAN) is a manual published by the World Health Organization designed to assess, measure, and classify the psycho-pathology and behavior associated with the major psychiatric syndromes of adult life. SCAN had its origins in the 9th edition of the Present State Examination (PSE 9). SCAN consists of 4 components: the 10th edition of the “Present State Examination” (PSE 10), the “Item Group Check List,” the “Clinical History Schedule,” and the “Glossary of Differential Definitions.” Only the first 3 were reviewed. The PSE 10, which forms the greater part of SCAN, covers phenomenology. The “Item Group Check List” is a method of obtaining information from case records and informants other than the patient himself or herself. The “Clinical History Schedule” is a method of checking or entering data relevant to the broader clinical and social history.
The PSE itemizes various domains and categories of psychopathology. For each phenomenological category an appropriate probe question is provided. The PSE does not give detailed definitions. These are contained in the “Glossary of Differential Definitions” which was unfortunately not available for review. This is regrettable since the SCAN can only be fully appreciated in the context of the glossary.
The SCAN is designed for epidemiological research rather than day-to-day clinical care. Data from the schedules are intended to be entered into a computer algorithm (C ATEGO-5) which processes the data. The output is a series of options including a range of profiles of symptoms, an index of definitions and ICD-10, and DSM-III-R diagnostic categories.
Interviewers who use SCAN must first address those factors that would interfere with access to psychopathology or indicate a need to adopt specific interview strategies. These include severe language disorders, cognitive impairment, severe behavioral disturbance, uncooperativeness, or the likelihood of a premature termination. The PSE 10 rating scales address various domains and categories of psychopathology. The domains contain overlapping phenomenological categories that can be confusing. For example, depersonalization and derealization, which are rightfully disturbances of perception, are also included in the domain of nervous tension. While this may be useful for research purposes and computerized programs, overlapping phenomenological categories muddy the analysis of the mental state. This is akin to describing motor weakness in a neurological patient within the domain of sensory changes. It is preferable to keep phenomenological categories within their rightful domains. Elicited psychopathology can then be extracted and linked together within the context of a biopsychosocial framework to reach a diagnosis.
The domains of the mental state identified by the PSE include: somatic symptoms, nervous tension, panic, anxiety and phobia, obsessional symptoms, depressed mood and ideation, thinking, concentration, energy and interests, body functions, eating disorders, expansive mood and ideation, alcohol and substance abuse, language difficulties, perceptual disorders other than hallucinations, hallucinations, subjectively described thought disorder and experience of replacement of will, delusions, cognitive impairment and/or decline, motor and behavioral phenomenology, observed affect, speech abnormalities, and social impairment.
SCAN contains a separate section for evaluating stress-causing acute reactions and posttraumatic stress disorders, the course of schizophrenia as described by either DSM-III-R or ICD-10, acute psychosis, induced psychotic disorder, schizotypal disorder, simple schizophrenia (an ICD-10 but not a DSM-III-R diagnosis), and the negative syndrome of schizophrenia. The latter has been included in SCAN for research purposes.
The section on cognitive impairment and/or decline includes the well-known Mini-Mental State Examination (MMSE) as well as the less well-known Verbal Trails Test. This section also contains probes to assess language, calculation, praxis, abstraction, fiind-of-knowledge, frontal-sub-cortical function, and level of consciousness. The section on dementia includes specific etiologies such as Alzheimer disease and Parkinson disease.
SCAN was developed by an international panel of researchers. Various groups of collaborators were responsible for the design and field trials of particular sections of SCAN. This presumably accounts for the lack of integration and the overlap of phenomenological categories across various psychopathological domains. In addition SCAN, unlike PSE 9, shifts out of the context of the mental state examination and includes sections that rate specific psychiatric disorders and disease course as well as identifies specific etiologies. SCAN is, therefore, much more than a rating scale for the mental state examination. Users of the SCAN may find this confusing and would be wise to look elsewhere for a clear and integrated conceptual understanding of the various domains and categories of the abnormal mental state. Nonetheless SCAN does list much of the psychopathology of mental disorders and can be used as a reference by clinicians to enrich and polish their own mental state evaluations.