Page 40 - Post-traumatic stress disorder in adults with mild intellectual disability: Screening, assessment, and brief intensive EMDR therapy

Chapter 2
Brief Symptom Inventory −18, Revised Dutch Version (BSI–18)
The BSI–18 (de Beurs, 1993) is a multidimensional (Dutch) instrument that
measures self-reported psychological distress and psychopathological
symptoms in adults aged 18 and over; it measures the most common
psychopathological symptoms. The questionnaire consists of 18 questions
scored on a 5-point Likert scale of distress (0 = not at all, 1 = a little bit,
2 = moderately, 3 = quite a bit, 4 = extremely). It takes approximately five
minutes to complete the questionnaire. The BSI yields a total score (eighteen
items) and consists of the following three primary symptom dimensions:
“Somatization” (six items), “Anxiety” (six items) and “Depression” (six items).
The BSI–18 has demonstrated sufficient to good psychometric properties,
specifically internal consistency and discriminant validity, for (Dutch)
individuals with MID-BIF (Wieland et al., 2012). In our study, Cronbach’s alpha
for the BSI-18 total score was .95, for “Somatization” .88, for “Depression”
.88 and for “Anxiety” .89, indicating good to excellent internal consistency.
Behavior Problems Inventory (BPI)
The BPI-01 (Rojahn et al., 2001) is an instrument used for the assessment
of self-injury, stereotyped behavior, and aggression/destruction in
individuals with ID. In our study, we used the Dutch version of the BPI. This,
instrument which is completed by proxy indexes the frequency and severity
of problem behaviors and consists of three subscales: “Self-injurious
behavior” (eight items), “Aggressive/destructive behavior” (ten items),
and “Stereotyped behavior” (twelve items). The frequency of the problem
behavior is measured on a 5-point Likert scale (0 = never, 1 = monthly,
2 = weekly, 3 = daily, and 4 = hourly). The respondent’s subjective judgment
of the severity of the problem is measured on a 3-point Likert scale (1 = mild
problem, 2 = moderate problem, 3 = severe problem). A mean score for
both frequency and severity was calculated for each subscale and for
problem behavior overall. The Dutch version of the BPI has been found
to show adequate to good psychometric properties, including interrater,
intrarater, internal consistency and good convergent validity, compared
with the Aberrant Behavior Checklist (Dumont et al., 2014). In our study,
Cronbach’s alpha for the BPI total score was .86 (frequency) and .88
(severity), for “Self-injury behavior” .75 (frequency) and .77 (severity), for
“Aggressive/destructive behavior” .81 (frequency) and .89 (severity) and
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