Interview for ICD-10 (CIDI). Superior to the MINI,
SCID-III-R and CIDI, the MINI-Plus has specific items
for the diagnosis of drug-induced mental disorders,
e.g. drug-induced psychotic disorder.
The prevalence rates of lifetime and current persecutory
delusion, thought reading, thought insertion,
delusion of reference, strange or unusual beliefs,
auditory hallucinations, and visual hallucinations
were rated by the patients’ responses (‘yes’ or ‘no’) to
the MINI-Plus questions. Although the MINI-Plus
separates bizarre and non-bizarre delusions, both
were combined as were the presence of delusions.
Disorganized speech, disorganized or catatonic behaviour,
and negative symptoms were assessed on the
basis of the patient’s behaviour observed during the
interview.
The Manchester scale was used to rate the severity
of these symptoms during the week prior to assessment
(Krawiecka et al., 1977). This scale was chosen
because it is brief but covers a number of positive,
disorganized, and negative symptoms found in most
psychotic disorders.
The prevalence rate of each psychotic symptom was
determined by its frequency obtained by the use of
MINI-Plus, Module M. The Manchester scale scores
were included in the factor analysis. All eight items of
the scale were subjected to principal-component
analysis for identifying the distinct factors. Eigenvalue
one test was applied to keep or discard factors. Finally,
varimax rotation was performed to elicit the factor
components.