The method used is that of a semi-structured standardized clinical interview, with cross-examination of the subject. The order in which the sections are done depends on the most important symptoms of the respondent. There is no fixed order. This makes the SCAN approach a very flexible and versatile one. It is very suitable for patients who are difficult to interview.
Each section starts with obligatory queries about symptoms of that particular section (e.g. general questions about panic attacks and phobias in the anxiety section). If these orienting queries are answered affirmatively or the interviewer has doubts, the questions below the cut-off point are also asked. Rating is done on the basis of matching the answers of the respondent against the definitions of the symptoms in the Glossary, which is an integral part of SCAN. All the symptoms and signs and classification items are defined in this Glossary, which is largely based on the phenomenology of Jaspers. Unlike instruments like the Composite International Diagnostic Interview (Robins et al ), where the decision about the clinical significance is based on a standard set of questions (the probe flow chart), with SCAN the interviewer decides what to rate on the basis of the subject’s information, always bearing the definitions and rating rules in mind.
Possible ratings are: symptom (sx) not present, present but below the severity of a sx, sx present to a moderate degree, sx present to a severe degree >50% of the reference period (usually, but not necessarily, the past month). Attributions to physical causes or to the use of psychoactive substances can be made for each item or for each section.
Each section starts with obligatory queries about symptoms of that particular section (e.g. general questions about panic attacks and phobias in the anxiety section). If these orienting queries are answered affirmatively or the interviewer has doubts, the questions below the cut-off point are also asked. Rating is done on the basis of matching the answers of the respondent against the definitions of the symptoms in the Glossary, which is an integral part of SCAN. All the symptoms and signs and classification items are defined in this Glossary, which is largely based on the phenomenology of Jaspers. Unlike instruments like the Composite International Diagnostic Interview (Robins et al ), where the decision about the clinical significance is based on a standard set of questions (the probe flow chart), with SCAN the interviewer decides what to rate on the basis of the subject’s information, always bearing the definitions and rating rules in mind.
Possible ratings are: symptom (sx) not present, present but below the severity of a sx, sx present to a moderate degree, sx present to a severe degree >50% of the reference period (usually, but not necessarily, the past month). Attributions to physical causes or to the use of psychoactive substances can be made for each item or for each section.
The following episode options are available:
- Present State: the past month by default, or extended to up to 6 weeks
- Representative Episode: a period during which the sx were present in a more charachteristic or severe degree. This could be any episode in the life of the subject.
- Lifetime Before (the subject’s entire life up to the Present State)
- Lifetime Ever (during the subject’s entire life).
After finishing the interview the data are entered into the entry programme (the laptop version of SCAN (Ishell) allows entering data directly). Subsequently the data are fed into algorithms for ICD-10 and DSM-IV diagnoses. These algorithms produce a diagnostic classification for both systems.