Emotion dysregulation and amygdala dopamine D2-type receptor availability in methamphetamine users

Abstract

Background: Individuals who use methamphetamine chronically exhibit emotional and dopaminergic neurochemical deficits. Although the amygdala has an important role in emotion processing and receives dopaminergic innervation, little is known about how dopamine transmission in this region contributes to emotion regulation. This investigation aimed to evaluate emotion regulation in subjects who met DSM-IV criteria for methamphetamine dependence, and to test for a relationship between self-reports of difficulty in emotion regulation and D2-type dopamine receptor availability in the amygdala.

Method: Ninety-four methamphetamine-using and 102 healthy-control subjects completed the Difficulties in Emotion Regulation Scale (DERS); 33 of those who used methamphetamine completed the Addiction Severity Index (ASI). A subset of 27 methamphetamine-group and 20 control-group subjects completed positron emission tomography with [(18)F]fallypride to assay amygdala D2-type dopamine receptor availability, measured as binding potential (BPND).

Results: The methamphetamine group scored higher than the control group on the DERS total score (p<0.001), with DERS total score positively correlated with the Drug Composite Score on the ASI (p=0.02) in the methamphetamine group. The DERS total score was positively correlated with amygdala BPND in both groups and the combined group of participants (combined: r=0.331, p=0.02), and the groups did not differ in this relationship.

Conclusion: These findings highlight problems with emotion regulation linked to methamphetamine use, possibly contributing to personal and interpersonal behavioral problems. They also suggest that D2-type dopamine receptors in the amygdala contribute to emotion regulation in both healthy and methamphetamine-using subjects.

Keywords: Amygdala; Dopamine; Emotion dysregulation; Methamphetamine; PET; [(18)F]Fallypride.

Figure 1. Association of Amygdala Dopamine D2-type receptor BP_ND with DERS total score

Scatter plots show individual data for the DERS scores (y-axis) and D2-type receptor binding potential (BP_ND) (x-axis) in amygdala for the Control group (blue circles) and MA group (red triangles). Black solid-line shows slope of relationship of all participants, while blue dashed- and red dashed- lines are for control group and MA group, respectively. DERS was correlated with amygdala BP_ND (control: r = 0.458, p = 0.042; MA: r = 0.424, p = 0.027).