The optimisation of experience sampling protocols in people with schizophrenia.

Experience sampling methodology (ESM) involves completing questionnaires during daily life and has been used extensively in people with schizophrenia to assess symptoms and behaviours. Despite considerable advantages over interview measures, there is limited information about its external validity. Our aim is to investigate whether ESM protocol implementation is affected differentially in people with schizophrenia and healthy individuals by factors such as mood, medication and symptoms which would have implications for validity. Fifty-three people with schizophrenia and fifty-eight controls from the general population completed seven ESM questionnaires per day for six consecutive days. Compliance and acceptability, including overall experience, training and disruption of normal routines, were recorded. Overall questionnaire completion rate in people with schizophrenia was comparable to controls (i.e. over 70%). People with schizophrenia completed significantly fewer questionnaires in the morning but did not show fatigue effects over the experience sampling period. Excluding questionnaires in the morning did not significantly alter the findings. In the schizophrenia group medication level and symptoms did not influence adherence. However, higher disruption was associated with reduced questionnaire completion in this group. These findings suggest that minimising disruption may enhance validity and completion rates. ESM is a valid methodology to use with people with schizophrenia.