Brain Effects of Escitalopram and Citalopram Using fMRI

Official Title: “A Comparison of the CNS Effects of Equivalent Doses of Escitalopram and Racemic Citalopram Using BOLD fMRI”

Escitalopram (Lexapro) and citalopram (Celexa) are similar selective serotonin reuptake inhibitors that alter blood flow to the amygdala and other brain structures involved in regulating mood. Escitalopram consists of S-citalopram while citalopram contains both S-citalopram and R-citalopram (racemic citalopram). There is evidence that R-citalopram may block the effects of S-citalopram. The hypothesis being tested is that because of the antagonist effect of R-citalopram, S-citalopram will have a greater effect on the mood circuit than racemic citalopram when equal doses of S-citalopram are administered. The study design consists of a two week medication period followed by blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) while viewing affective visual stimuli.

Intervention(s) in this Clinical Trial

• Drug: Escitalopram
  • One week of escitalopram taken orally at 10 mg followed by one week at 20 mg daily.
• Drug: Citalopram
  • One week of citalopram taken orally at 20 mg followed by one week at 40 mg daily.
• Drug: Placebo
  • Two weeks of placebo taken orally.

Arms, Groups and Cohorts in this Clinical Trial

• Active Comparator: Escitalopram
  • One week of escitalopram at 10 mg followed by one week at 20 mg in healthy volunteers.
• Active Comparator: Citalopram
  • One week of citalopram at 20 mg followed by one week at 40 mg in healthy volunteers.
• Placebo Comparator: Placebo
  • Two weeks of placebo in healthy volunteers.

Primary Measures

• Change in BOLD fMRI signal in regions of interest including prefrontal cortex, orbitofrontal cortex, caudate, anterior cingulate gyrus, amygdala, and hippocampus.
  • Time Frame: Two weeks (each medication period)
    Safety Issue?: No

Inclusion Criteria:

• Healthy male aged 21 to 50 years.
• Capable of providing informed consent.
• Has an established residence and phone.

Exclusion Criteria:

• Meets DSM-IV criteria for an Axis I or II disorder.
• History of substance dependence or abuse within the past month.
• Use of NSAID's, beta blockers, calcium channel blockers, antidepressants, antipsychotic medications, lithium or other medication which in the opinion of the investigator would alter vascular responsivity.
• Regular use of sedative hypnotic or narcotic medication, or other medication that might affect the individual's perception of visual stimuli.
• History of cataracts or significant visual impairment.
• A medical condition, which in the opinion of the investigator is likely to affect the individual's perception of the visual stimuli or vascular response.
• Participation in a research protocol that included administration of medication within the past 3 months.
• Cigarette smoking.

Gender Eligibility for this Clinical Trial: Male

Minimum Age for this Clinical Trial: 21 Years

Maximum Age for this Clinical Trial: 50 Years

Are Healthy Volunteers Accepted for this Clinical Trial?: Accepts Healthy Volunteers

Lead Investigator: Steward St. Elizabeth's Medical Center of Boston, Inc. Other

Overall Clinical Trial Officials and Contacts

Michael E Henry, MD Principal Investigator Steward St. Elizabeth's Medical Center of Boston, Inc.  

Information obtained from ClinicalTrials.gov on February 02, 2012

Link to the current ClinicalTrials.gov record. http://clinicaltrials.gov/show/NCT00825825

Study ID Number: 00397

ClinicalTrials.gov Identifier: NCT00825825

Health Authority: United States: Institutional Review Board