Baseline Working Memory Predicted Response to Low-Dose Ketamine Infusion in Patients with Treatment-Resistant Depression

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.

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Efficacy of low-dose ketamine infusion in anxious vs nonanxious depression: revisiting the Adjunctive Ketamine Study of Taiwanese Patients with Treatment-Resistant Depression

CNS Spectrums ◽

10.1017/s1092852920001194 ◽

2020 ◽

pp. 1-6

Author(s):

Mu-Hong Chen ◽

Wei-Chen Lin ◽

Hui-Ju Wu ◽

Ya-Mei Bai ◽

Cheng-Ta Li ◽

...

Keyword(s):

Depressive Symptoms ◽

Low Dose ◽

Rating Scale ◽

Estimating Equation ◽

Antidepressant Effect ◽

Treatment Resistant Depression ◽

Treatment Resistant ◽

Ketamine Infusion ◽

Resistant Depression

Abstract Background. The antidepressant effect of low-dose ketamine infusion on Taiwanese patients with anxious vs nonanxious treatment-resistant depression (ANX-TRD vs NANX-TRD) has remained unknown. Methods. In total, 71 patients with TRD were randomized to three groups. Each group had participants who received saline infusions mixed with 0 (a normal saline infusion), 0.2, and 0.5 mg/kg of ketamine. Participants were followed up for 2 weeks. Anxious depression was defined as major depressive disorder with a total score of 7 or more on the 17-item Hamilton Depression Rating Scale Anxiety-Somatization factor. Generalized estimating equation models were used to investigate the effects of treatment (ketamine vs placebo) and depression type (ANX-TRD vs NANX-TRD) in the reduction of depressive symptoms during the follow-up period. Results. Patients with ANX-TRD were less likely to respond to a single low-dose ketamine infusion than those with NANX-TRD. Among patients with NANX-TRD, low-dose ketamine infusion was significantly superior to placebo for reducing depressive symptoms. However, among patients with ANX-TRD, ketamine was not superior to placebo; nonetheless, approximately 30% of the patients responded to ketamine infusion compared to 13% who responded to the placebo. Conclusions. Low-dose ketamine infusion was effective for Taiwanese patients with NANX-TRD but not so effective for those with ANX-TRD. A higher level of anxiety severity accompanying depression was related to greater depression severity. This may confound and reduce the antidepressant effect of ketamine infusion.

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