Brain Microstructure and Impulsivity Differ between Current and Past Methamphetamine Users

Abstract

Methamphetamine (Meth) use disorder continues to be highly prevalent worldwide. Meth users have higher impulsivity and brain abnormalities that may be different between current and past Meth users. The current study assessed impulsivity and depressive symptoms in 94 participants (27 current Meth users, 32 past Meth users and 35 non-drug user controls). Additionally, brain microstructure was assessed using diffusion tensor imaging (DTI); fractional anisotropy (FA) and mean diffusivity (MD) were assessed in the striatum, and FA, MD, radial and axial diffusivity were quantified in five white matter structures using DtiStudio.Across the three subject groups, current users had the highest self-reported impulsivity scores, while both Meth user groups had larger striatal structures than the controls. Past Meth users had the highest FA and lowest MD in the striatum, which is likely due to greater magnetic susceptibility from higher iron content and greater dendritic spine density. In white matter tracts, current Meth users had higher AD than past users, indicating greater water diffusion along the axons, and suggesting inflammation with axonal swelling. In contrast, past users had the lowest AD, indicating more restricted diffusion, which might have resulted from reactive gliosis. Although current Meth users had greater impulsivity than past users, the brain microstructural abnormalities showed differences that may reflect different stages of neuroinflammation or iron-induced neurodegeneration. Combining current and past Meth users may lead to greater variability in studies of Meth users. Longitudinal studies are needed to further evaluate the relationship between recency of Meth use and brain microstructure.

Molecular, Behavioral, and Physiological Consequences of Methamphetamine Neurotoxicity: Implications for Treatment

“…As previously indicated, METH users also display affective symptoms, including depression (London et al, 2004), psychotic symptoms (Sekine et al, 2002(Sekine et al, , 2003, impulsivity (Andres et al, 2016), or aggressive behavior (Sekine et al, 2006). Sensitization to METH psychosis could be functionally related to neurotoxicity because psychiatric symptoms correlated inversely with DAT density in the striatum and PFC (Sekine et al, 2003).…”

Cognition and Related Neural Findings on Methamphetamine Use Disorder: Insights and Treatment Implications From Schizophrenia Research

“…Inhibitory control and impulsivity are associated (129). Indeed, people with schizophrenia or meth use disorder both display poor impulse control (24,25,36,38,42,130,131). Notably, impulse-related functions are among the most impaired in meth use disorder (76), and poor impulsivity is regarded as one key predisposing factor to developing substance use disorder (132).…”

“…Meth dependents also display structural abnormalities in the genu of the corpus callosum (138,139), a white matter tract which carries fibers originating from the PFC. Poorer corpus callosum integrity is associated with impaired inhibition (140,141) and impulse control (38). In addition to structural abnormalities, people with meth use disorder display reduced activation of the PFC when performing the Stroop task (56), more specifically in the right inferior frontal gyrus (IFG), ACC (23) and the PFC (26).…”

Cannabis use in patients with early psychosis is associated with alterations in putamen and thalamic shape

“…Increased putamen grey matter volume (Moreno-Alcázar et al, 2018) and cerebral blood flow (Filbey, Aslan, Lu, & Peng, 2018) have been shown in healthy cannabis users compared to controls. Increased putamen volume has been shown to be associated with methamphetamine use (Andres et al, 2016;Chang et al, 2005;Jan, Lin, Miles, Kydd, & Russell, 2012), with alterations in putamen myeleoarchitecture in those at behavioural risk of addiction (Nord et al, 2019), and increased putamen volumes in probands with stimulant addiction and relatives of those with addictive disorder (Ersche et al, 2012). Two previous studies have examined cannabis use in the context of psychosis: one showed putamen volume increases in cannabis-using compared to non-using PwP (Koenders et al, 2015), whereas the other found neurochemical changes in the left putamen with higher NAA/choline ratio in cannabis-using PwP compared to controls (Malchow et al, 2013).…”