What are delusions? Examining the typology problem

Delusions are a heterogenous transdiagnostic phenomenon with a higher prevalence in schizophrenia. One of the most fundamental debates surrounding the philosophical understanding of delusions concerns the question about the type of mental state in which reports that we label as delusional are grounded, namely, the typology problem. The formulation of potential answers for this problem seems to have important repercussions for experimental research in clinical psychiatry and the development of psychotherapeutic tools for the treatment of delusions in clinical psychology. Problematically, such alternatives are scattered in the literature, making it difficult to follow the current development and state of the target discussion. This paper offers an updated critical examination of the alternatives to the typology problem currently available in the literature. After clarifying the two main philosophical views underlying the dominant formulation of the debate (interpretivism and functionalism), we follow the usual distinction between doxastic (the idea that delusions are a type of belief) and anti-doxastic views. We then introduce two new sub-distinctions; on the doxastic camp, we distinguish between revisionist and non-revisionist proposals; on the anti-doxastic camp, we distinguish between commonsensical and non-commonsensical anti-doxasticisms. After analyzing the main claims of each view, we conclude with some of the most fundamental challenges that remain open within the discussion. This article is categorized under: Philosophy > Foundations of Cognitive Science Philosophy > Consciousness Philosophy > Psychological Capacities Neuroscience > Cognition.

Functional Behavioral Assessment-based interventions on adults' delusions, hallucinations and disorganized speech: A single case meta-analysis

The Functional Behavioral Assessment (FBA) approach involves the use of single-case designs (SCD) to study the problem behavior-environment contingencies and conduct interventions that consider this functional relationship. Although this approach has been considered an evidence-based practice (EBP) for the treatment of several psychological problems, no meta-analytic studies of FBA-based interventions on delusions, hallucinations and disorganized speech -commonly operationalized as "atypical vocalizations"- have been carried out. Therefore, the purpose of this study was to review and synthesize the results of FBA-based interventions on adults' atypical vocalizations. We conducted a systematic review and a multi-level meta-analysis of these interventions, using a recently developed effect size estimator for SCD studies (i.e., log response ratio). All the studies that met our eligibility criteria provided evidence supporting the effectiveness of FBA-based interventions on atypical vocalizations, with an overall average effect size of a 72% reduction. Both the publication year and the methodological quality were found to be significant moderators. Despite some methodological limitations, we can conclude that FBA-based interventions are effective to reduce atypical vocalizations. The implications of these results could be of interest for the mental health community.