The MDQ is a brief, self-report, and easy-to-use inventory, which is
used to screen for bipolar spectrum disorders according to the DSM-IV
criteria of a lifetime history of a manic and hypomanic episode
(Hirschfeld et al., 2000). The questionnaire consists of three sections.
The first part consists of 13 brief “yes” or “no” statements related to
manic and hypomanic symptoms. The second part has one “yes” or
“no” question, which asks whether those manic symptoms occurred
simultaneously. The third part has the subject evaluate the problems
caused by those manic behaviors along a 4-point scale, ranging from
“no problem” to “serious problem.” A scoring algorithm is used to
calculate the number of symptom items scored “yes” (ranged from 0 to
13). In order to screen positive for bipolar spectrum disorder, in addition
to a threshold number of symptom items (7 or more), the respondent
has to check “yes” for the item asking if the symptoms clustered in the
same time period and has to indicate that the symptoms caused either
“moderate” or “serious” problems. The original study reported that the
sensitivity and the specificity of the MDQ were 0.65 and 0.94,
respectively (Hirschfeld et al., 2000). The English version of the MDQ
used in the present study was translated into Japanese by Dr. Naganuma
and Dr. Utsumi (private communication); however, the reliability and
validity of the Japanese translation have not been investigated.