Uncovering the realities of delusional experience in schizophrenia: a qualitative phenomenological study in Belgium

In the mental health field, there is a growing awareness that the study of psychiatric symptoms in the context of everyday life, using experience sampling methodology (ESM), may provide a powerful and necessary addition to more conventional research approaches. ESM, a structured self‐report diary technique, allows the investigation of experiences within, and in interaction with, the real‐world context. This paper provides an overview of how zooming in on the micro‐level of experience and behaviour using ESM adds new insights and additional perspectives to standard approaches. More specifically, it discusses how ESM: a) contributes to a deeper understanding of psychopathological phenomena, b) allows to capture variability over time, c) aids in identifying internal and situational determinants of variability in symptomatology, and d) enables a thorough investigation of the interaction between the person and his/her environment and of real‐life social interactions. Next to improving assessment of psychopathology and its underlying mechanisms, ESM contributes to advancing and changing clinical practice by allowing a more fine‐grained evaluation of treatment effects as well as by providing the opportunity for extending treatment beyond the clinical setting into real life with the development of ecological momentary interventions. Furthermore, this paper provides an overview of the technical details of setting up an ESM study in terms of design, questionnaire development and statistical approaches. Overall, although a number of considerations and challenges remain, ESM offers one of the best opportunities for personalized medicine in psychiatry, from both a research and a clinical perspective.

We did a systematic review and meta-analysis to investigate the magnitude and specificity of the “jumping to conclusions” (JTC) bias in psychosis and delusions. We examined the extent to which people with psychosis, and people with delusions specifically, required less information before making decisions. We examined (1) the average amount of information required to make a decision and (2) numbers who demonstrated an extreme JTC bias, as assessed by the “beads task.” We compared people with psychosis to people with and without nonpsychotic mental health problems, and people with psychosis with and without delusions. We examined whether reduced data-gathering was associated with increased delusion severity. We identified 55 relevant studies, and acquired previously unpublished data from 16 authors. People with psychosis required significantly less information to make decisions than healthy individuals (k = 33, N = 1935, g = −0.53, 95% CI −0.69, −0.36) and those with nonpsychotic mental health problems (k = 13, N = 667, g = −0.58, 95% CI −0.80, −0.35). The odds of extreme responding in psychosis were between 4 and 6 times higher than the odds of extreme responding by healthy participants and participants with nonpsychotic mental health problems. The JTC bias was linked to a greater probability of delusion occurrence in psychosis (k = 14, N = 770, OR 1.52, 95% CI 1.12, 2.05). There was a trend-level inverse association between data-gathering and delusion severity (k = 18; N = 794; r = −.09, 95% CI −0.21, 0.03). Hence, nonaffective psychosis is characterized by a hasty decision-making style, which is linked to an increased probability of delusions.