title: Does neuroimaging research examining the pathophysiology of posttraumatic stress disorder require medication-free patients?
abstract: BACKGROUND
  In an attempt to avoid unknown influence, most neuroimaging studies examining the pathophysiology of posttraumatic stress disorder (PTSD) exclude patients taking medications. Here we review the empirical evidence for relevant medications having a confounding effect on task performance or cerebral blood flow (CBF) in this population. The evidence for potentially confounding effects of psychotherapy in PTSD are also discussed.
  
  
  METHODS
  The literature that we reviewed was obtained through a PubMed search from 1980 to 2009 using the search terms posttraumatic stress disorder, PTSD, psychotropic medications, neuroimaging, functional magnetic resonance imaging, positron emission tomography, cerebral blood flow, CBF, serotonin-specific reuptake blocker, benzodiazepine, ketamine, methamphetamine, lamotrigine and atypical antipsychotic agents.
  
  
  RESULTS
  The empirical evidence for relevant medications having a confounding effect on task performance or CBF in relevant areas remains sparse for most psychotropic medications among patients with PTSD. However, considerable evidence is accumulating for 2 of the most commonly prescribed medication classes (serotonin-specific reuptake inhibitors and benzodiazepines) in healthy controls. Compelling data for the potentially confounding effects on brain areas relevant to PTSD for psychotherapeutic interventions are also accumulating.
  
  
  CONCLUSIONS
  Neuroimaging studies examining the pathophysiology of PTSD should ideally recruit both medicated (assuming that the medication treatment has not resulted in the remission of symptoms) and unmedicated participants, to allow the findings to be generalized with greater confidence to the entire population of patients with PTSD. More research is needed into the independent effects of medications on task performance and CBF in regions of interest in PTSD. Neuroimaging studies should also take into account whether patients are currently engaged in psychotherapeutic treatment.
authors.affiliation: Department of Psychiatry, University of Western Ontario, London, Ont., Canada. ruth.lanius@lhsc.on.ca
authors.forename: Ruth A
authors.initials: RA
authors.lastname: Lanius
authors.forename: Chris R
authors.initials: CR
authors.lastname: Brewin
authors.forename: J Douglas
authors.initials: JD
authors.lastname: Bremner
authors.forename: Judith K
authors.initials: JK
authors.lastname: Daniels
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Friedman
authors.forename: Israel
authors.initials: I
authors.lastname: Liberzon
authors.forename: Alexander
authors.initials: A
authors.lastname: McFarlane
authors.forename: Paula P
authors.initials: PP
authors.lastname: Schnurr
authors.forename: Lisa
authors.initials: L
authors.lastname: Shin
authors.forename: Murray
authors.initials: M
authors.lastname: Stein
authors.forename: Eric
authors.initials: E
authors.lastname: Vermetten
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000503:physiopathology*; D002491:Central Nervous System Agents / Q000494:pharmacology*; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology; D003952:Diagnostic Imaging / Q000379:methods*; D006801:Humans; D013313:Stress Disorders, Post-Traumatic / Q000188:drug therapy* / Q000503:physiopathology*
chemical_list: D002491:Central Nervous System Agents