Decreased Thalamic Volumes in Adolescent Inhalant Users from Korea and Australia

Objectives: Research investigating the impact of inhalant misuse on brain structure suggests abnormalities in subcortical regions. We investigated the association between inhalant misuse and subcortical brain volumes in adolescents.

Methods: Based on a collaborative dataset from South Korea (inhalant users: N = 15, mean age = 16.7, SD = 1.1; controls: N = 15, mean age = 15.4, SD = 1.2) and Australia (inhalant users: N = 7, mean age = 18.2, SD = 1.4; controls: N = 7, mean age = 18.9, SD = 2.6), the volumes of caudate nucleus, putamen, pallidum, amygdala, hippocampus, and thalamus were estimated in adolescent inhalant users and healthy adolescents using FreeSurfer.

Results: The results revealed a significantly decreased right thalamic volume in adolescent inhalant users (P = 0.042), along with a trend-level decrease in left thalamic volume (P = 0.061). A negative correlation (r = -0.544; P = 0.036) between thalamic volume and severity of inhalant use (i.e., reduced volumes associated with greater use) was identified among Korean participants.

Conclusions: These findings suggest that compared with other subcortical structures, the thalamus is particularly sensitive to damage following chronic inhalant exposure during adolescence.