Relationship of Alexithymia Ratings to Dopamine D2-type Receptors in Anterior Cingulate and Insula of Healthy Control Subjects but Not Methamphetamine-Dependent Individuals

• Published in: The international journal of neuropsychopharmacology Vol. 19; no. 5; p. pyv129
• Main Authors: Okita, Kyoji, Ghahremani, Dara G., Payer, Doris E., Robertson, Chelsea L., Mandelkern, Mark A., London, Edythe D.
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 01.05.2016
• Subjects: Adolescent; Adult; Affective Symptoms - metabolism; Affective Symptoms - physiopathology; Affective Symptoms - psychology; Alexithymia; Amphetamine-Related Disorders - metabolism; Amphetamine-Related Disorders - physiopathology; Amphetamine-Related Disorders - psychology; Benzamides - administration & dosage; Case-Control Studies; Central Nervous System Stimulants - adverse effects; Cerebral Cortex - chemistry; Cerebral Cortex - drug effects; Cerebral Cortex - physiopathology; Dopamine; Emotions - drug effects; Female; Gyrus Cinguli - chemistry; Gyrus Cinguli - drug effects; Gyrus Cinguli - physiopathology; Humans; Magnetic Resonance Imaging; Male; Methamphetamine; Methamphetamine - adverse effects; Middle Aged; Positron-Emission Tomography; Pyrrolidines - administration & dosage; Radiopharmaceuticals - administration & dosage; Receptors, Dopamine D2 - analysis; Synaptic Transmission; Young Adult; alexithymia; emotion processing; Methamphetamine dependence; dopamine; PET
• ISSN: 1461-1457; 1469-5111; 1469-5111
• DOI: 10.1093/ijnp/pyv129

Background:Individuals with substance-use disorders exhibit emotional problems, including deficits in emotion recognition and processing, and this class of disorders also has been linked to deficits in dopaminergic markers in the brain. Because associations between these phenomena have not been explored, we compared a group of recently abstinent methamphetamine-dependent individuals (n=23) with a healthy-control group (n=17) on dopamine D2-type receptor availability, measured using positron emission tomography with [18F]fallypride.Methods:The anterior cingulate and anterior insular cortices were selected as the brain regions of interest, because they receive dopaminergic innervation and are thought to be involved in emotion awareness and processing. The Toronto Alexithymia Scale, which includes items that assess difficulty in identifying and describing feelings as well as externally oriented thinking, was administered, and the scores were tested for association with D2-type receptor availability.Results:Relative to controls, methamphetamine-dependent individuals showed higher alexithymia scores, reporting difficulty in identifying feelings. The groups did not differ in D2-type receptor availability in the anterior cingulate or anterior insular cortices, but a significant interaction between group and D2-type receptor availability in both regions, on self-report score, reflected significant positive correlations in the control group (higher receptor availability linked to higher alexithymia) but nonsignificant, negative correlations (lower receptor availability linked to higher alexithymia) in methamphetamine-dependent subjects.Conclusions:The results suggest that neurotransmission through D2-type receptors in the anterior cingulate and anterior insular cortices influences capacity of emotion processing in healthy people but that this association is absent in individuals with methamphetamine dependence.