Are the effects of cannabis dependence on glucose metabolism similar to schizophrenia? An FDG PET understanding

Abstract

Background:Cannabis has been associated with transient psychotic states; however, the causal relationship between cannabis and schizophrenia continues to remain a matter of debate. Epidemiological and some biological studies hint at cannabis being an independent risk factor for schizophrenia; this has not been definitively proved.Aims:We aimed to understand the patterns of glucose uptake in important brain regions among individuals with cannabis dependence and schizophrenia. Furthermore, we compared the interregional metabolic rates in pertinent neural circuits among individuals with cannabis dependence, schizophrenia and normal controls.Setting and Design:This is a case-control cross-sectional study that was carried out by a general psychiatry department in collaboration with a nuclear diagnosis unit.Materials and Methods:Male volunteers with cannabis dependence, schizophrenia and normal controls underwent FDG PET scanning. Glucose uptakes in pre-selected regions of interest were compared using MANOVA. Finally, Chow tests were used to compare interregional metabolic relationships in the mesocortical and cortical-subcortical-cerebellum circuits.Results:Significant differences (P<0.05) were noted among individuals with cannabis dependence and schizophrenia in the medial and lateral temporal regions. When the neural circuits were compared, significant interregional differences (P<0.05) were noted between individuals with cannabis dependence and normal controls. However, among individuals with cannabis dependence and schizophrenia, no significant differences (P>0.05) were noted in these patterns.Conclusions:Our findings suggest that cannabis dependence can alter interregional relationships in a manner similar to schizophrenia. This indicates that cannabis could potentially play a role in the development of psychosis by altering neural circuits.

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

“…They inferred that cannabis can affect developing neurons in a manner similar to that seen in schizophrenia; in other words, cannabis seems to have schizophrenogenic biological effects. Similar results were found in a study with 18-FDG-PET scanning (18-fluoro-2-deoxyglucose positron emission tomography), in which it was found that cannabis could potentially play a role in the development of psychosis by altering neural circuits [8]. In contrast, Delisi et al [9] failed to confirm any neurotoxic effects of cannabis on developing neurons.…”

Structural and metabolic differentiation between bipolar disorder with psychosis and substance-induced psychosis: An integrated MRI/PET study

“…Nonetheless, it is worth remarking that the magnetic resonance imaging (MRI) research reported that psychotic symptoms in BD are associated with reduced gray matter (GM) density and connectivity in several prefrontal, temporal and limbic regions in both adult [11,12] and pediatric [13] BD patients. Similarly, it is still not fully elucidated how the co-occurrence of substance abuse may interact with psychosis in affecting the bipolar brain [14,15]. In this context, it is worth noting that the disruptive metabolic and morphological effects of substance abuse have been reported in heavy drug abusers, independently of the drug used, in several brain regions, including prefrontal [16–19], temporal [16] and cerebellar [20] cortices as well as subcortical areas [21].…”

Roles of facilitative glucose transporter GLUT1 in [18F]FDG positron emission tomography (PET) imaging of human diseases

“…[ 18 F]FDG PET has also been used to investigate the effects of antipsychotic drugs [220][221][222][223], cannabis use [224,225] and auditory verbal hallucinations [226,227] on the pattern of cerebral glucose metabolism in schizophrenia and to differentiate it from the pattern in bipolar disorder [228]. A hypothesis for pathogenesis of schizophrenia based on impaired neuronal glucose uptake by GLUT1…”