How does the PAS-ADD Clinical Interview differ from the
other PAS-ADD assessments?
One of the greatest differences between the assessment of people with intellectual disabilities (ID)
and of the general population is the huge emphasis placed on what other people say, rather than on
what the clients themselves say. The reasons for this are obvious, but there is always a danger of
underestimating the potential contribution a person can actually make. Nothing can replace the
patient’s own verbal report, so instruments that are specifically designed to interview people with ID
can be of great benefit. The Clinical Interview is the only one of the PAS-ADD assessment tools that
is designed for both for face-to-face interviewing of people with ID (and also for informant
interviewing). In terms of diagnosis, the Mini PAS-ADD and the ChA-PAS provide diagnostic
thresholds in relation to classes of disorder such as anxiety and psychosis, while the Clinical
Interview provides specific diagnoses of a wide range of disorders, exactly as specified by both ICD10 and DSM-IV (TR). Psychosis, in particular, is covered far more extensively in the Clinical
Interview.
Thus, the Clinical Interview is the assessment tool of choice if any of the following apply:



the person has at least some language
if precise diagnostic evaluations under ICD-10 or DSM-IV (TR) are desired
if psychotic symptoms are present.
Wider case formulation
In addition, the score form for the PAS-ADD Clinical Interview has a section enabling information
from other sources to be brought together with the mental health findings to structure the process of
case formulation. This can include scores from the Mini PAS-ADD and ChA-PAS, as well as other
mental health assessments. There are also sections for physical status, behavioural assessments,
challenging behaviour, and ecological and psychodynamic aspects to be included. The aim is to
provide a framework within which all these perspectives can be considered, so that hypotheses can
be formulated about why the person has reached this point in their lives.
The following pages illustrate how the PAS-ADD Clinical Interview works in relation to these
various aspects.
Please note that some sections are blurred out for copyright reasons.
Interviewing people with ID and their informants
The Clinical Interview provides specific questions for the person with ID and for an informant. The
following example is the first item in the depression section: depressed mood.
Questions
for the
person with
ID
Informant
questions
Diagnosis of specific conditions
This illustration shows the scoring for two of the five anxiety disorders that are covered by the
Clinical Interview. Note how the differences between ICD-10 and DSM-IV (TR) are handled. In
both these cases DSM-IV (TR) does not require specific evidence of autonomic symptoms, while
ICD-10 does. Also, the number of symptoms required for the diagnosis of a specific phobia differs
between the two systems.
Hatched boxes
relate to
differences
between ICD-10
and DSM-IV (TR)
Scoring for
two
different
episodes
In this case, the
ICD-10 requires
both criteria, while
DSM-IV (TR)
requires only the
first
Diagnosing psychotic problems
The rating scales in the psychosis section focus on the certainty that a symptom is present, rather
than on the severity. Particular weight is given to the rating of symptoms that are corroborated by a
clear and convincing account from the patient him/herself. Below is the general psychosis rating
scale that is used for many of the items.
Where it is appropriate, detailed questions are available to ask about the specific nature of symptoms.
The following is one of the questions relating to hearing voices.
Negative symptoms, and positive symptoms relating to disordered language, are particularly difficult
to evaluate in people with ID because they are often present in the absence of psychosis. The Clinical
Interview’s rating criteria are designed to enable appropriate weight to be give to such symptoms, if
they are present.
Many different types of delusion can be coded. The following is the checklist of non-bizarre
delusions.
‘Query’ ratings indicate that
the symptom may be
present, but is not certain
enough to make a definite
rating
The top rating is only given
if the patient has given a
credible verbal report of
the symptom
One challenging aspect of diagnosing psychotic illness is the relationship between the psychotic
symptoms and any mood symptoms that may be present. The PAS-ADD Clinical Interview provides
a logical and structured approach to determining (a) whether the final diagnosis should be primary
psychosis or a primary mood disorder, and (b) the correct diagnosis to make.
This first image shows the rating guidelines in the interview that are used to rate the interviewer’s
judgement of this relationship.
The second image (on the next page), shows how, in the score form, this rating is used to arrive at the
final diagnosis.
Rating categories in the interview
A page from the score form showing how the rating above is used to complete the diagnostic
process in the psychosis section.
Comprehensive case formulation
The final section of the Clinical Interview’s score form provides a framework into which many other
pieces of information can be drawn together. The aim of this section is to provide a logical,
structured approach to reviewing the evidence, on which the final formulation will be made. Often
there are several possible hypotheses about why the person is showing the problems that they have.
Our experience of using this framework shows that the very process of drawing the information
together often highlights areas where further information is needed. It can be seen from this image
that the various pieces of information are judged on their relevance to the case formulation, and it is
from these judgements that the key elements of the case are identified. These key elements can then
be used to derive the diagnostic hypotheses. Also on this page is the section on requests for further
information.