# Morphological Brain Alterations and Network Disorganizations in Individuals With Substance Use Disorders: Differential Effects of Heroin Versus Methamphetamine

## TL;DR

This study shows that heroin and methamphetamine cause different brain changes, with heroin affecting overall brain communication and methamphetamine damaging specific brain areas.

## Contribution

The study reveals distinct morphological and network-level brain alterations specific to heroin and methamphetamine addiction.

## Key findings

- Heroin users showed widespread network disruption and atrophy in somatosensory cortex regions.
- Methamphetamine users exhibited localized damage in brain hubs related to memory and visual processing.
- Brain changes were linked to drug use patterns and psychological symptoms like anxiety and depression.

## Abstract

Heroin and methamphetamine are two widely abused drugs that have profound effects on brain morphology and functioning. This study aims to (1) identify brain structural differences between heroin and methamphetamine users; (2) examine how these drugs differentially affect the topology and functional connectivity of key brain networks; and (3) characterize associations between morphological alterations and clinical symptoms, including anxiety and depression.

In this study, we collected T1‐weighted magnetic resonance imaging data from 26 heroin‐abstinent (HA) patients, 24 methamphetamine‐abstinent (MA) patients, and 32 healthy controls (HC). All participants were in early abstinence (< 6 months) to minimize acute intoxication and withdrawal confounds while capturing residual brain alterations. Four surface‐based morphological features, including cortical thickness (CT), fractal dimension (FD), gyrification index (GI), and sulcal depth (SD), were analyzed, and morphological brain networks were constructed using Jensen‐Shannon divergence with 210 cortical regions from the Brainnetome Atlas.

Both patient groups showed brain tissue thinning in hearing‐related areas (temporal cortex) and reduced depth in visual processing regions. Heroin users specifically exhibited atrophy in somatosensory cortex regions associated with touch sensation whereas methamphetamine users demonstrated distinctive cortical folding alterations in motor cortex areas related to movement control. Network analysis revealed that heroin users had widespread connection problems affecting brain communication efficiency, while methamphetamine users showed localized damage in specific brain hubs important for memory, attention, and visual processing. Clinical correlations revealed that morphological changes were significantly associated with drug use patterns (frequency and dosage) and psychological symptoms, with anxiety scores negatively correlating with SD in heroin users and depression scores positively correlating with morphological measures in methamphetamine users.

Our findings demonstrate distinct neurobiological signatures of heroin and methamphetamine addiction that persist during early abstinence. Heroin primarily causes widespread network disruption, while methamphetamine leads to focal hub damage. The observed associations between brain morphology and clinical symptoms indicate the practical importance of these structural alterations. These distinct patterns may inform the development of substance‐specific treatment approaches.

Our morphological brain network analysis of 82 participants reveals that these substances leave dramatically different fingerprints that persist even in recovery, with heroin causing global network collapse through increased path lengths across the entire cortex, while methamphetamine selectively damages temporal parietal, and visual processing centers.