Psychomotor slowing as a predictor of fluoxetine nonresponse in depressed outpatients.
OBJECTIVE
This study examined the utility of baseline psychomotor speed, measured with neuropsychological tests, to predict fluoxetine response in moderately depressed outpatients. The authors hypothesized that since psychomotor slowing in depressed patients has been linked to reduced dopaminergic neurotransmission, patients with slowing would be unresponsive to fluoxetine, a selective serotonin reuptake inhibitor.


METHODS
After baseline neuropsychological testing, patients were treated openly with fluoxetine for 12 weeks. Thirty-seven patients completed the trial.


RESULTS
Compared to the 25 patients who responded, the 12 patients who did not respond to fluoxetine exhibited significantly poorer performance in verbal fluency on the Controlled Oral Word Association Test FAS and in color naming on the Stroop Color and Word Test. In addition, the nonresponders tended to perform worse than the responders on the Stroop Color and Word Test reading subtest and the WAIS-III digit symbol subtest. Differential treatment response was specific to psychomotor speed because responders and nonresponders did not perform differently on tasks of executive functioning, attention, visuospatial functioning, or verbal intelligence.


CONCLUSIONS
Psychomotor slowing may identify a subgroup of depressed patients who have a dopaminergic deficit that is unresponsive to fluoxetine monotherapy and who should therefore receive an alternative treatment.
Taylor
Bonnie P
BP
Depression Evaluation Service, New York State Psychiatric Institute, Department of Psychiatry, Columbia University College of Physicians and Surgeons, 1051 Riverside Dr., New York, NY 10032, USA. taylorb@pi.cpmc.columbia.edu
Bruder
Gerard E
GE
Stewart
Jonathan W
JW
McGrath
Patrick J
PJ
Halperin
Jeffrey
J
Ehrlichman
Howard
H
Quitkin
Frederic M
FM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000553:Ambulatory Care; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000188:drug therapy* / Q000523:psychology; D004298:Dopamine / Q000172:deficiency / Q000502:physiology; D005260:Female; D005473:Fluoxetine / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011336:Probability; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance / Q000187:drug effects* / Q000502:physiology; D012307:Risk Factors; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D012720:Severity of Illness Index; D009435:Synaptic Transmission / Q000187:drug effects; D016896:Treatment Outcome
D004298:Dopamine; D005473:Fluoxetine; D017367:Selective Serotonin Reuptake Inhibitors