title: White matter microstructure and impulsivity in methamphetamine dependence with and without a history of psychosis.
abstract: Methamphetamine (MA) use may lead to white matter injury and to a range of behavioral problems and psychiatric disorders, including psychosis. The present study sought to assess white matter microstructural impairment as well as impulsive behavior in MA dependence and MA-associated psychosis (MAP).
  
  
  
  Thirty patients with a history of MAP, 39 participants with MA dependence and 40 healthy controls underwent diffusion tensor imaging (DTI). Participants also completed the UPPS-P impulsive behavior questionnaire. We applied tract-based spatial statistics (TBSS) to investigate group differences in mean diffusivity (MD), fractional anisotropy (FA), axial (λ‖ ) and radial diffusivity (λ⊥ ), and their association with impulsivity scores and psychotic symptoms.
  
  
  
  The MAP group displayed widespread higher MD, λ‖ and λ⊥ levels compared to both controls and the MA group, and lower FA in extensive white matter areas relative to controls. MD levels correlated positively with negative psychotic symptoms in MAP. No significant DTI group differences were found between the MA group and controls. Both clinical groups showed high levels of impulsivity, and this dysfunction was associated with DTI measures in frontal white matter tracts.
  
  
  
  MAP patients show distinct patterns of impaired white matter integrity of global nature relative to controls and the MA group. Future work to investigate the precise nature and timing of alterations in MAP is needed. The results are further suggestive of frontal white matter pathology playing a role in impulsivity in MA dependence and MAP. Hum Brain Mapp 37:2055-2067, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Psychiatry and Mental Health, University of Cape Town, South Africa.
authors.forename: Anne
authors.initials: A
authors.lastname: Uhlmann
authors.affiliation: Department of Psychiatry and Mental Health, University of Cape Town, South Africa.|Department of Psychiatry, University of Stellenbosch, Cape Town, South Africa.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Fouche
authors.affiliation: Department of Psychiatry and Mental Health, University of Cape Town, South Africa.
authors.forename: Katharina
authors.initials: K
authors.lastname: Lederer
authors.affiliation: Department of Human Biology, University of Cape Town, MRC/UCT Medical Imaging Research Unit, South Africa.
authors.forename: Ernesta M
authors.initials: EM
authors.lastname: Meintjes
authors.affiliation: Department of Psychiatry and Mental Health, University of Cape Town, South Africa.
authors.forename: Don
authors.initials: D
authors.lastname: Wilson
authors.affiliation: Department of Psychiatry and Mental Health, University of Cape Town, South Africa.
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Stein
mesh_terms: D000293:Adolescent; D000328:Adult; D019969:Amphetamine-Related Disorders / Q000150:complications / Q000000981:diagnostic imaging* / Q000523:psychology*; D001921:Brain / Q000000981:diagnostic imaging* / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000009:adverse effects; D056324:Diffusion Tensor Imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007175:Impulsive Behavior; D008297:Male; D008694:Methamphetamine / Q000008:administration & dosage / Q000009:adverse effects; D010363:Pattern Recognition, Automated; D011569:Psychiatric Status Rating Scales; D011605:Psychoses, Substance-Induced / Q000000981:diagnostic imaging* / Q000523:psychology; D011795:Surveys and Questionnaires; D066127:White Matter / Q000000981:diagnostic imaging* / Q000187:drug effects; D055815:Young Adult
chemical_list: D000697:Central Nervous System Stimulants; D008694:Methamphetamine
keywords: TBSS; anisotropy; brain; diffusion tensor imaging; diffusivity; impulsive behavior; psychostimulant; psychotic disorders