Brain Metabolism in Substance-Induced Psychosis and Schizophrenia: A Preliminary PET Study

Abstract

Introduction: The relation between schizophrenia and cannabis abuse has been widely discussed from etiopathogenetic, psychopathological and neurometabolic points of view. Relatively little has been written about the differences between schizophrenia with co-occurrent cannabis abuse and substance-induced psychotic disorder (SIPD). Given these premises, our study aims to investigate the psychopathological and neurometabolic features of these clinical entities. Methods: We enrolled patients experiencing an acute psychotic episode, affected either by schizophrenia with or without cannabis abuse (SCZ +/- CA; n = 5 and n = 5, respectively) with recent onset (<5 years of illness) or by SIPD (n = 6), as diagnosed by the Structured Clinical Interview for DSM-IV Axis I. Patients affected by SIPD were all cannabis abusers. All patients were assessed with the PANSS (Positive and Negative Scale for Schizophrenia), urinary toxicological tests and brain 18-FDG-PET scanning in resting condition. Statistical analysis (ANOVA) was performed with Statistical Parametric Mapping SPM8 and Scenium software. Results: Bilateral hypermetabolism in the posterior cingulum and the precuneus (p < 0.001) was observed in SIPD patients compared to patients with schizophrenia, with or without cannabis abuse. Conclusions: Our preliminary PET findings suggest that substance abuse may cause increased brain metabolism in patients with induced psychosis but not in those with schizophrenia. These differences in brain metabolism were found in the posterior cingulum and precuneus, which are two core regions of the default mode network in humans. © 2014 S. Karger AG, Basel

Short‐term outcome of substance‐induced psychotic disorder in a large UK first episode psychosis cohort

“…There may also be some differences due to the type of substance inducing the psychotic disorder . There is also work investigating whether there are neurobiological differences to distinguish these two diagnostic groups . We found no differences other than prior history of substance use to distinguish these groups at baseline in our cohort.…”

Diverse definitions of the early course of schizophrenia—a targeted literature review

“…requiring patients to be in an acute phase of the disease or in a stable phase or remission). 30 , 32 , 36 , 37 , 40 , 48 , 67 , 76 – 78 , 100 , 137 , 172 , 173 , 178 – 185 All of these studies used the symptom severity criteria in combination with a duration or episode-based definition. It should be noted that in many of the first-episode studies it was often implied that these patients were in the acute phase of an episode, however as symptom severity was not a formal patient selection criterion these studies were therefore not included under this definition type.…”

Psicosis inducida por cannabis: características clínicas y su diferenciación con la esquizofrenia con y sin consumo de cannabis asociado

“…En relación a los trabajos que abordan el concepto de psicosis inducida, la mayoría incluyen pacientes con un diagnóstico de psicosis inducidas por sustancias y aquellos con un diagnóstico de esquizofrenia y abuso de sustancias (Caton, Samet y Hasin, 2000;Dawe et al, 2011;Fraser et al, 2012) sin determinar que la psicosis inducida sea por cannabis o por otras drogas. Tan solo dos estudios también consideran una tercera cohorte de pacientes: pacientes con un diagnóstico de esquizofrenia que no tenían abuso o dependencia de otras sustancias (Dragogna et al, 2014;Weibell et al, 2013). De ellos, tan solo el trabajo de Dragogna et al (2014), habla específicamente de cannabis como sustancia de abuso y de psicosis inducida por cannabis.…”

“…Tan solo dos estudios también consideran una tercera cohorte de pacientes: pacientes con un diagnóstico de esquizofrenia que no tenían abuso o dependencia de otras sustancias (Dragogna et al, 2014;Weibell et al, 2013). De ellos, tan solo el trabajo de Dragogna et al (2014), habla específicamente de cannabis como sustancia de abuso y de psicosis inducida por cannabis. Además, debido a los criterios de inclusión muestral, los trabajos realizados hasta la fecha han sido heterogéneos respecto a la muestra seleccionada, incluyendo PEP con consumo o no de cannabis, esquizofrenia con antecedentes de consumo de cannabis o no, o comparación entre pacientes crónicos y episodios agudos considerando el consumo o los resultados de un análisis toxicológico.…”