title: Interhemispheric insular and inferior frontal connectivity are associated with substance abuse in a psychiatric population.
abstract: Substance abuse is highly comorbid with major psychiatric disorders. While the neural underpinnings of drug abuse have been studied extensively, most existing studies compare drug users without comorbidities and healthy, non-user controls. Such studies do not generalize well to typical patients with substance abuse disorders. Therefore, we studied a population of psychiatric inpatients (n = 151) with a range of mental illnesses. Psychiatric disorders were diagnosed via structured interviews. Sixty-five percent of patients met criteria for at least one substance use disorder. Patients were recruited for resting state functional connectivity (RSFC) and diffusion tensor imaging (DTI) experiments to examine the interhemispheric connectivity between brain regions hypothesized to be involved in drug addiction, namely: the inferior, medial, and superior frontal gyri; insula; striatum; and anterior cingulate cortex. The World Health Organization Alcohol, Smoking, and Substance Involvement Screening Test (WHOA) questionnaire was used to further assess drug use. An association between use of tobacco, alcohol, cocaine, sedatives, and hallucinogens with increased insular interhemispheric connectivity was observed. In addition, increased inferior frontal gyrus interhemispheric connectivity was associated with amphetamine and inhalant use. Our results suggest that increased inter-hemispheric insula connectivity is associated with the use of several drugs of abuse. Importantly, psychiatric inpatients without a history of drug dependence were used as an ecologically valid control group rather than the more typical comparison between "mentally ill vs. healthy control" populations. We suggest that dysfunction of interhemispheric connectivity of the insula and to a lesser extent of the inferior frontal gyrus, are related to drug abuse in psychiatric populations.
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, 77030, USA.
authors.forename: Humsini
authors.initials: H
authors.lastname: Viswanath
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, 77030, USA.
authors.forename: Kenia M
authors.initials: KM
authors.lastname: Velasquez
authors.affiliation: Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA.
authors.forename: Ricky
authors.initials: R
authors.lastname: Savjani
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, 77030, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Molfese
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, 77030, USA.
authors.forename: Kaylah
authors.initials: K
authors.lastname: Curtis
authors.affiliation: Department of Psychology, University of Connecticut, Mansfield, CT, 06269, USA; Haskins Laboratories, New Haven, CT, 06511, USA.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Molfese
authors.affiliation: Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Eagleman
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, 77030, USA.
authors.forename: Philip R
authors.initials: PR
authors.lastname: Baldwin
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, 77030, USA; University of Hawaii, Department of Psychology, Hilo, HI, USA.
authors.forename: B Christopher
authors.initials: BC
authors.lastname: Frueh
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, 77030, USA.
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Fowler
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, 77030, USA. Electronic address: rsalas@bcm.edu.
authors.forename: Ramiro
authors.initials: R
authors.lastname: Salas
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002540:Cerebral Cortex / Q000473:pathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007297:Inpatients; D008279:Magnetic Resonance Imaging; D008297:Male; D001523:Mental Disorders / Q000150:complications* / Q000473:pathology; D008875:Middle Aged; D009415:Nerve Net / Q000473:pathology*; D011569:Psychiatric Status Rating Scales; D019966:Substance-Related Disorders / Q000209:etiology* / Q000473:pathology*; D055815:Young Adult
keywords: Diffusion tensor imaging; Drug abuse; Inferior frontal gyrus; Inpatient; Insula; Resting state functional connectivity