Antidepressant and neurocognitive effects of isoflurane anesthesia versus electroconvulsive therapy in refractory depression.
BACKGROUND
Many patients have serious depression that is nonresponsive to medications, but refuse electroconvulsive therapy (ECT). Early research suggested that isoflurane anesthesia may be an effective alternative to ECT. Subsequent studies altered drug, dose or number of treatments, and failed to replicate this success, halting research on isoflurane's antidepressant effects for a decade. Our aim was to re-examine whether isoflurane has antidepressant effects comparable to ECT, with less adverse effects on cognition.


METHODS
Patients with medication-refractory depression received an average of 10 treatments of bifrontal ECT (n = 20) or isoflurane (n = 8) over 3 weeks. Depression severity (Hamilton Rating Scale for Depression-24) and neurocognitive responses (anterograde and retrograde memory, processing speed and verbal fluency) were assessed at Pretreatment, Post all treatments and 4-week Follow-up.


RESULTS
Both treatments produced significant reductions in depression scores at Post-treatment and 4-week Follow-up; however, ECT had modestly better antidepressant effect at follow-up in severity-matched patients. Immediately Post-treatment, ECT (but not isoflurane) patients showed declines in memory, fluency, and processing speed. At Follow-up, only autobiographical memory remained below Pretreatment level for ECT patients, but isoflurane patients had greater test-retest neurocognitive score improvement.


CONCLUSIONS
Our data reconfirm that isoflurane has an antidepressant effect approaching ECT with less adverse neurocognitive effects, and reinforce the need for a larger clinical trial.
Department of Psychiatry, University Neuropsychiatric Institute, University of Utah School of Medicine, Salt Lake City, Utah, United States of America. Howard.Weeks@hsc.utah.edu
Howard R
HR
Weeks
Scott C
SC
Tadler
Kelly W
KW
Smith
Eli
E
Iacob
Mikala
M
Saccoman
Andrea T
AT
White
Joshua D
JD
Landvatter
Gordon J
GJ
Chelune
Yana
Y
Suchy
Elaine
E
Clark
Michael K
MK
Cahalan
Lowry
L
Bushnell
Derek
D
Sakata
Alan R
AR
Light
Kathleen C
KC
Light
D000293:Adolescent; D000328:Adult; D000368:Aged; D000648:Amnesia, Retrograde / Q000503:physiopathology / Q000628:therapy; D000758:Anesthesia; D000928:Antidepressive Agents / Q000494:pharmacology / Q000627:therapeutic use*; D003071:Cognition / Q000187:drug effects; D003710:Demography; D061218:Depressive Disorder, Treatment-Resistant / Q000188:drug therapy / Q000503:physiopathology* / Q000628:therapy*; D004565:Electroconvulsive Therapy; D056344:Executive Function / Q000187:drug effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007530:Isoflurane / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D055815:Young Adult
D000928:Antidepressive Agents; D007530:Isoflurane