The dual nature of working memory deficits: methamphetamine abusers have more impaired social working memory capacity than canonical working memory capacity.

Social working memory (WM) temporarily retains and manipulates various aspects of social information. Extensive research has highlighted impaired social cognitive functions in individuals with substance addiction. However, the specific deficit in social WM within this population remains notably understudied. Bridging this gap, we investigated social WM capacity using biological motion (BM) stimuli in methamphetamine (MA) abusers compared to an inmate control group, alongside contrasting these findings with their canonical WM deficits. Across two studies, we recruited female MA abusers (N = 80) undergoing post-isolation rehabilitation within a mandatory confinement circumstance. To ensure a pertinent comparison, we recruited female inmates (N = 80) subjected to comparable confinement. Results show substantial BM WM impairment in MA abusers, yet non-BM WM remains mostly intact. These findings highlight a pronounced social WM deficit in MA abusers, surpassing their canonical WM deficit relative to inmate controls. This suggests a distinct dissociation between social and canonical WM processing.