Measurement properties of the Illness Perception Questionnaire in practitioners working with patients with co-morbid schizophrenia and learning disability

Abstract

Rationale, aims and objectives: The widely-used Illness Perception Questionnaire (IPQ) adapted for use in patients with major mental health problems and those who care and work with them, was originally developed for evaluating the illness perceptions of patients with physical pathology. There have been concerns expressed regarding the appropriateness of the IPQ and derivative measures of it in axis I disorders such as schizophrenia. The current investigation examined the measurement characteristics of a modified version of the IPQ in mental health practitioners working with patients with schizophrenia co-morbid with learning disability. Method: Two hundred and ten mental health practitioners working with patients with schizophrenia co-morbid with learning disability participated in the study. Contemporary models of the measurement structure of the IPQ were evaluated using confirmatory factor analysis. The internal reliability of the IPQ was also evaluated. Results: Single factor, 5-factor and 6-factor models were evaluated against data. All models were found to offer a poor fit to the data. The internal reliability of the measure was also found to be unsatisfactory overall. Conclusions: Consistent with one previous study that has found poor measurement characteristics of the IPQ when used in the context of schizophrenia, the current study found the measure to be a poorly performing index of illness perceptions. Echoing previous observations of the use of this tool in axis I disorder, it is recommended that a new measure of illness perceptions be developed using contemporary research methodology sensitive to the context of psychotic illness in order to provide a more effective tool for the provision of person-centered psychiatry and healthcare.

Psychometric Evaluation of Family Illness Perceptions of Relatives with Schizophrenia

“…One [27] reported that, for the IPQ-R in German-speaking outpatients with chronic schizophrenia, the personal control and illness coherence subscales (Cronbach's α: 0.52, 0.48) did not have acceptable levels of internal consistency (> 0.70), but test-retest correlations in all subscales significant. Two others [9,28] also reported low Cronbach α values in treatment control and personal control in a test of the IPQ-R for healthcare professionals. Another two [3,12], however, reported satisfactory internal reliability for all IPQ-R subscales in a test for caregivers of relatives with schizophrenia.…”

Psychometric evaluation of the Perinatal Illness Perceptions Scale (PIPS)

“…The current study sought to determine the psychometric robustness and applied utility of the IPQ-R (Moss-Morris et al , 2002) “causes” and “consequences” derived domains developed for PMH. Noteworthy prior to discussion of the empirical findings is that the focus on these particular domains was informed by work from a previous study (Jomeen et al , 2014), as per Fleming et al (2009) and Martin et al (2016) application of the IPQ-R sub-scales to mental health contexts is seemingly problematic in terms of measurement veracity, in a way which it is not in a physical health context (Arat et al , 2016) which may be fundamental to the underlying dimensional structure as envisaged by Moss-Morris et al (2002).…”

“…A cross-sectional design and instrument evaluation approach taken to investigate the psychometric properties of the PIPS. Validity and reliability evaluation of the PIPS was undertaken using established statistical approaches (Kline, 2000; Martin and Savage-McGlynn, 2013; Martin et al , 2016).…”

Professional issues in maternal mental health scale (PIMMHS): The development and initial validation of a brief and valid measure

“…Validity and reliability evaluation of the PIMMHS were undertaken using established statistical approaches [22][23][24] .…”