title: Regional cerebral metabolic asymmetries replicated in an independent group of patients with panic disorders.
abstract: BACKGROUND
  Abnormal left/right (L/R) hemispheric ratios of regional cerebral glucose metabolic rates (rCMRglc) (hippocampus and inferior prefrontal cortex) have been noted in unmedicated panic disorder patients.
  
  
  METHODS
  An independent group of panic disorder patients placed on imipramine was studied with positron-emission tomography, testing for evidence of normalization versus persistence of the abnormal rCMRglc ratios. Differences in orbital frontal rCMRglc values between the imipramine-treated and the previously reported unmedicated panic disorder patients were tested examining for evidence that the differences would resemble those noted in obsessive-compulsive disorder (OCD) patients treated with clomipramine.
  
  
  RESULTS
  We found the same abnormally low L/R hippocampal and posterior inferior prefrontal rCMRglc ratios in the imipramine-treated panic disorder patients. In addition, we found posterior orbital frontal rCMRglc decreases in the imipramine-treated panic disorder patients compared with the unmedicated panic disorder patients.
  
  
  CONCLUSIONS
  These abnormal asymmetries found in unmedicated panic disorder patients and now in imipramine-treated panic disorder patients may reflect a trait abnormality. The orbital frontal rCMRglc differences between the imipramine-treated and unmedicated patients are similar to changes noted in OCD patients treated with clomipramine and may reflect direct or indirect effects of imipramine treatment in panic disorder patients.
authors.affiliation: Department of Psychiatry, UC Davis Medical Center, Sacramento, California, USA.
authors.forename: T E
authors.initials: TE
authors.lastname: Nordahl
authors.forename: M B
authors.initials: MB
authors.lastname: Stein
authors.forename: C
authors.initials: C
authors.lastname: Benkelfat
authors.forename: W E
authors.initials: WE
authors.lastname: Semple
authors.forename: P
authors.initials: P
authors.lastname: Andreason
authors.forename: A
authors.initials: A
authors.lastname: Zametkin
authors.forename: T W
authors.initials: TW
authors.lastname: Uhde
authors.forename: R M
authors.initials: RM
authors.lastname: Cohen
mesh_terms: D000328:Adult; D000929:Antidepressive Agents, Tricyclic / Q000627:therapeutic use; D001923:Brain Chemistry / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D005947:Glucose / Q000378:metabolism; D006624:Hippocampus / Q000000981:diagnostic imaging / Q000378:metabolism; D006801:Humans; D007099:Imipramine / Q000627:therapeutic use; D008297:Male; D016584:Panic Disorder / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000523:psychology; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging / Q000378:metabolism; D014055:Tomography, Emission-Computed
chemical_list: D000929:Antidepressive Agents, Tricyclic; D005947:Glucose; D007099:Imipramine