title: Relationship of Alexithymia Ratings to Dopamine D2-type Receptors in Anterior Cingulate and Insula of Healthy Control Subjects but Not Methamphetamine-Dependent Individuals.
abstract: 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 [(18)F]fallypride.
  
  
  
  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.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences (Drs Okita, Ghahremani, and London), Department of Molecular and Medical Pharmacology (Drs Robertson and London), and Brain Research Institute (Dr London), University of California Los Angeles, Los Angeles, CA; Addiction Imaging Research Group, Centre for Addiction and Mental Health, Toronto, Ontario, Canada (Dr Payer); Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada (Dr Payer); Department of Research, VA Greater Los Angeles Healthcare System, Los Angeles, CA (Drs Okita, Robertson, Mandelkern, and London); Department of Physics, University of California Irvine, Irvine, CA (Dr Mandelkern).
authors.forename: Kyoji
authors.initials: K
authors.lastname: Okita
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences (Drs Okita, Ghahremani, and London), Department of Molecular and Medical Pharmacology (Drs Robertson and London), and Brain Research Institute (Dr London), University of California Los Angeles, Los Angeles, CA; Addiction Imaging Research Group, Centre for Addiction and Mental Health, Toronto, Ontario, Canada (Dr Payer); Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada (Dr Payer); Department of Research, VA Greater Los Angeles Healthcare System, Los Angeles, CA (Drs Okita, Robertson, Mandelkern, and London); Department of Physics, University of California Irvine, Irvine, CA (Dr Mandelkern).
authors.forename: Dara G
authors.initials: DG
authors.lastname: Ghahremani
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences (Drs Okita, Ghahremani, and London), Department of Molecular and Medical Pharmacology (Drs Robertson and London), and Brain Research Institute (Dr London), University of California Los Angeles, Los Angeles, CA; Addiction Imaging Research Group, Centre for Addiction and Mental Health, Toronto, Ontario, Canada (Dr Payer); Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada (Dr Payer); Department of Research, VA Greater Los Angeles Healthcare System, Los Angeles, CA (Drs Okita, Robertson, Mandelkern, and London); Department of Physics, University of California Irvine, Irvine, CA (Dr Mandelkern).
authors.forename: Doris E
authors.initials: DE
authors.lastname: Payer
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences (Drs Okita, Ghahremani, and London), Department of Molecular and Medical Pharmacology (Drs Robertson and London), and Brain Research Institute (Dr London), University of California Los Angeles, Los Angeles, CA; Addiction Imaging Research Group, Centre for Addiction and Mental Health, Toronto, Ontario, Canada (Dr Payer); Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada (Dr Payer); Department of Research, VA Greater Los Angeles Healthcare System, Los Angeles, CA (Drs Okita, Robertson, Mandelkern, and London); Department of Physics, University of California Irvine, Irvine, CA (Dr Mandelkern).
authors.forename: Chelsea L
authors.initials: CL
authors.lastname: Robertson
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences (Drs Okita, Ghahremani, and London), Department of Molecular and Medical Pharmacology (Drs Robertson and London), and Brain Research Institute (Dr London), University of California Los Angeles, Los Angeles, CA; Addiction Imaging Research Group, Centre for Addiction and Mental Health, Toronto, Ontario, Canada (Dr Payer); Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada (Dr Payer); Department of Research, VA Greater Los Angeles Healthcare System, Los Angeles, CA (Drs Okita, Robertson, Mandelkern, and London); Department of Physics, University of California Irvine, Irvine, CA (Dr Mandelkern).
authors.forename: Mark A
authors.initials: MA
authors.lastname: Mandelkern
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences (Drs Okita, Ghahremani, and London), Department of Molecular and Medical Pharmacology (Drs Robertson and London), and Brain Research Institute (Dr London), University of California Los Angeles, Los Angeles, CA; Addiction Imaging Research Group, Centre for Addiction and Mental Health, Toronto, Ontario, Canada (Dr Payer); Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada (Dr Payer); Department of Research, VA Greater Los Angeles Healthcare System, Los Angeles, CA (Drs Okita, Robertson, Mandelkern, and London); Department of Physics, University of California Irvine, Irvine, CA (Dr Mandelkern). elondon@mednet.ucla.edu.
authors.forename: Edythe D
authors.initials: ED
authors.lastname: London
mesh_terms: D000293:Adolescent; D000328:Adult; D000342:Affective Symptoms / Q000378:metabolism* / Q000503:physiopathology / Q000523:psychology; D019969:Amphetamine-Related Disorders / Q000378:metabolism* / Q000503:physiopathology / Q000523:psychology; D001549:Benzamides / Q000008:administration & dosage; D016022:Case-Control Studies; D000697:Central Nervous System Stimulants / Q000009:adverse effects*; D002540:Cerebral Cortex / Q000737:chemistry / Q000187:drug effects* / Q000503:physiopathology; D004644:Emotions / Q000187:drug effects*; D005260:Female; D006179:Gyrus Cinguli / Q000737:chemistry / Q000187:drug effects* / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008694:Methamphetamine / Q000009:adverse effects*; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011759:Pyrrolidines / Q000008:administration & dosage; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D017448:Receptors, Dopamine D2 / Q000032:analysis*; D009435:Synaptic Transmission; D055815:Young Adult
chemical_list: D001549:Benzamides; D000697:Central Nervous System Stimulants; C581293:DRD2 protein, human; C094948:N-((1-allyl-2-pyrrolidinyl)methyl)-5-(3-fluoropropyl)-2,3-dimethoxybenzamide; D011759:Pyrrolidines; D019275:Radiopharmaceuticals; D017448:Receptors, Dopamine D2; D008694:Methamphetamine
keywords: Methamphetamine dependence; PET; alexithymia; dopamine; emotion processing