Abstract
Introduction Pretreatment neurocognitive function may predict the
treatment response to low-dose ketamine infusion in patients with
treatment-resistant depression (TRD). However, the association between working
memory function at baseline and the antidepressant efficacy of ketamine infusion
remains unclear.
Methods A total of 71 patients with TRD were randomized to one of three
treatment groups: 0.5 mg/kg ketamine, 0.2 mg/kg
ketamine, or normal saline. Depressive symptoms were measured using the 17-item
Hamilton Depression Rating Scale (HDRS) at baseline and after treatment.
Cognitive function was evaluated using working memory and go-no-go tasks at
baseline.
Results A generalized linear model with adjustments for demographic
characteristics, treatment groups, and total HDRS scores at baseline revealed
only a significant effect of working memory function (correct responses and
omissions) on the changes in depressive symptoms measured by HDRS at baseline
(F=12.862, p<0.05). Correlation analysis further showed a
negative relationship (r=0.519, p=0.027) between pretreatment
working memory function and changes in HDRS scores in the
0.5 mg/kg ketamine group.
Discussion An inverse relationship between pretreatment working memory
function and treatment response to ketamine infusion may confirm that low-dose
ketamine infusion is beneficial and should be reserved for patients with
TRD.
Repeated Transcranial Magnetic Stimulation (rTMS) to improve Electroconvulsive Therapy (ECT) in Treatment-Resistant Depression: A Report of Two Cases