Functional connectivity abnormalities underlying mood disturbances in male abstinent methamphetamine abusers

Area of Science:

• Neuroscience
• Psychiatry
• Addiction Research

Background:

• Methamphetamine (METH) abuse is linked to significant anxiety and depression, common withdrawal symptoms that increase relapse risk.
• Current pharmacotherapies for METH abuse and its withdrawal symptoms are lacking, highlighting the need for understanding underlying neuromechanisms.
• Effective clinical strategies and patient care for METH abuse depend on elucidating the neural basis of METH withdrawal and associated affective disturbances.

Purpose of the Study:

• To investigate brain network functional connectivity (FC) abnormalities in abstinent METH abusers (MAs).
• To examine the association between these brain network alterations and affective symptoms (anxiety and depression).
• To explore the role of specific brain regions, like the right rostral anterior cingulate cortex (rACC), in mediating the relationship between abstinence duration and symptom severity.

Main Methods:

• Recruited 48 male abstinent MAs and 48 age-gender matched healthy controls.
• Utilized resting-state functional magnetic resonance imaging (fMRI) to assess brain functional connectivity.
• Employed Independent Component Analysis (ICA) for network analysis and regression models to correlate FC with clinical measures (Hamilton Anxiety and Depression Rating Scales).

Main Results:

• MAs showed reduced intra-network FC in the cerebellar network and increased intra-network FC in the posterior salience network compared to controls.
• FC strength in the right rostral anterior cingulate cortex (rACC) within the ventromedial network (VMN) was significantly associated with affective symptom severity in MAs.
• The intra-network FC of the rACC within the VMN mediated the relationship between the duration of abstinence and the severity of affective symptoms.

Conclusions:

• Methamphetamine abuse is associated with distinct alterations in brain functional networks, including the cerebellar and posterior salience networks.
• The functional connectivity of the rACC within the VMN serves as a key neural substrate linking abstinence length to affective symptom severity in MAs.
• These findings offer crucial insights into the neurobiological underpinnings of METH addiction and withdrawal, potentially guiding future therapeutic interventions.