a) Early assessments and ad hoc measurement of illness representations
Early measurements of illness representations consisted of a mixture of closed and open ended questions. Open ended questions are often times used by researchers at first to assess the content of an illness belief. Thus, the use of open ended questions informs scale development for closed ended questions and allows the adaptation of the illness representation construct to a new area of illness beliefs.
- Identity was assessed with a question,
such as "Do you have a name for the condition" (yes/no),
and a follow-up, open-ended question "Can you tell me what
it is?" "How can you tell?" (Diefenbach
& Leventhal, 1996). In other instances, when
the patient does not know the identity of a condition, the
occurrence of commonly experienced symptoms (i.e., pain,
headaches, breathlessness, and sleep difficulties) has been
assessed. Patients answer items on a 5-point rating scale
(1 = not at all - 5 = very) or a yes/no dichotomous scale
Petrie, Moss-Morris, & Horne, 1996).
- Timeline can be assessed with the following question: "Do you think your condition is something that will go away after a couple of days, such as a cold; will come and go, such as an allergy; or you will have forever, such as diabetes?" Patients select the option that best fits their beliefs.
- The Consequence attribute can be assessed with the following question: "Do you think your symptom/condition is minor, severe, or life threatening?" Patients are asked to select the option that best fits their beliefs.
- Causal attributes have been assessed with threat-specific causes, often derived from patient interviews or focus groups. For example, "Please indicate how much you agree or disagree with the following reasons as causes for your symptom/condition." (Format e.g., 1 = completely disagree; 5 = completely agree).
- The control/cure attribute can be assessed with a question such as, "Something can be done to cure the symptom/condition (1 = completely disagree - 5 = completely agree).
b) The Illness Perception Questionnaire (IPQ)
The popularity of the self-regulation approach among researchers
prompted the development of a measure to systematically assess
the five illness representation attributes with 38 items (Illness
Perception Questionnaire, IPQ; Weinman
et al, 1996). Illness Identity
is assessed with a 12-item core symptom list that is answered
on a four-point Likert scale (1 = never; 2 = occasionally;
3 = frequently; 4 = all of the time). Core symptoms focus
on general symptomatology, such as pain, nausea, breathlessness,
weight loss, fatigue, stiff joints, sore eyes, headaches,
upset stomach, sleep difficulties, dizziness, and loss of
strength. The remaining four illness representation attributes,
cause, timeline, consequences and control/cure are rated on
a 5-point Likert scale (1 = strongly disagree; 3 = neither
agree or disagree 5 = strongly agree). The cause attribute
is assessed with 10 items, representing common causal beliefs.
The timeline attribute is assessed with three items. The consequence
attribute is assessed with seven statements. Finally, the
control/cure attribute is assessed with six statements.
The IPQ had been used with diverse patient populations suffering
from conditions, such as heart disease (Cooper
et. al., 1999,) cancer (Buick,
1997), arthritis (Murphy
et. al., 1999), diabetes
et. al., 2000), and chronic fatigue syndrome
studies found strong support for the existence of the six
illness representation attributes. The IPQ can be tailored
for use across many different illnesses by modifying the question
stem and by altering the instructions to focus on the specific
illness under investigation.
c) The Illness Perception Questionnaire-Revised (IPQ-R)
The IPQ-R was developed to improve the measurement
properties of two of the subscales (i.e., cure/control and
timeline) and to broaden the scope or the original IPQ (Moss-Morris,
Weinman, Petrie, Horne, Cameron, and Buick; 2002).
The cure/control subscale now distinguishes between personal
control and self-efficacy beliefs (six items) and treatment
control and outcome expectations (five items). For example,
new items that were added to the personal control scale are
"The course of my illness depends on me;" and "Nothing I do
will affect my illness." New items added to the treatment
control subscale include "My treatment can control my illness"
and "There is nothing which can help my condition." The second
subscale that was improved was the timeline subscale that
now includes 10 items, including those that assess cyclical
beliefs (e.g., "My symptoms come and go in cycles;" My illness
is very unpredictable.").
Another aspect of the IPQ-R that was neglected in the original conceptualization is the assessment of emotional representations.
Leventhal's self-regulation model specifies that individuals have emotional representations and reactions to the health threat, which might
lead to emotion-based coping behavior. Consequently, six items assessing emotional representations have been included, such as "I get
depressed when I think about my illness;" "Having this illness makes me feel anxious." The final addition was a subscale measuring a person's
overall coherent understanding of an illness. This illness-related "meta-cognition" is measured with five items, such as "My illness is a
mystery to me;" and "I have a clear picture or understanding of my condition." In total, the IPQ-R consists of 71 items divided into twelve
subscales. Psychometric analyses were performed on several patient samples, totaling a combined population of N = 711 patients.
Weinman, Petrie, Horne, Cameron, and Buick (2002)
used eight different illness groups for the validation of
the IPQ-R, including HIV, multiple sclerosis, asthma and type
II diabetes patients. Psychometric analysis revealed that
all of the IPR-R subscales demonstrate good internal reliability.
Cronbach alpha's range from 0.79 to 0.89 for the timeline
cyclical dimension and the timeline acute/chronic dimension
et al., 2002).
Test-Retest reliability was investigated at two time points
over a three-week period. Pearson's correlations ranged from
.46 for personal control beliefs to an average of .85 for
different risk factor attributions, demonstrating adequate
stability for a short time frame.
To determine discriminant validity and to ensure that the IPQ-R dimensions are not just reflective of affective dispositions, Pearson's
correlations were computed between the subscales of the Positive and Negative Affect Scale (PANAS). Correlations between the two PANAS
subscales and the all of the subscales of the IPQ were generally small to moderate in size, with the most significant relationship between
emotional representations and negative affect (NA) (r =. 54). This correlation suggested that approximately 29% of the variance of the emotional
reaction to illness was accounted for by trait negative affect.
Predictive stability of the IPQ was evaluated with regard to adjustment to illness among MS patients. Illness representations predicted 15%
of the variance of adjustment to disease controlling for illness severity. Among the six illness representations, the identity representation was the strongest predictor.
The large number of items of the IPQ-R and the associated
time commitment to complete the measure might be perceived
as an impediment to its widespread use. For that reason, Cameron
and colleagues have used a shortened version of the IPQ-R
Booth, Schlatter, Ziginskas, Harman, & Benson; 2005) consisting of a shortened version of
the personal control and emotional representation subscales.
The personal control scale uses three of the six items and
the emotional representation subscale uses four out of six
items. The authors report that analyses with data from the
original validation study demonstrated that the two subscales
exhibited comparable discriminate and convergent validity
with questionnaires of other illness beliefs and negative