<b><i>Introduction:</i></b> Ketamine has emerged as a rapid-acting antidepressant. While ongoing treatment can prevent relapse, concerns exist regarding long-term exposure. <b><i>Objective:</i></b> We conducted a randomized trial to examine the feasibility and efficacy of cognitive behavioral therapy (CBT) following intravenous ketamine in treatment-resistant depression (TRD). <b><i>Methods:</i></b> Subjects with TRD were recruited and treated with 6 intravenous infusions of ketamine over 3 weeks. Subjects who experienced a clinical response (≥50% improvement in depression severity) were then randomized to receiving CBT or treatment as usual (TAU) for an additional 14 weeks, using a sequential treatment model. <b><i>Results:</i></b> Of the 42 patients who signed consent, 28 patients achieved a response and were randomized to CBT or TAU. When measured using the Montgomery-Asberg Depression Rating Scale (primary outcome measure), the effect size at the end of the study was moderate (Cohen <i>d</i> = 0.65; 95% CI –0.55 to 1.82), though the group-by-time interaction effect was not significant. There was a significant group-by-time interaction as measured by the Quick Inventory of Depressive Symptomatology (<i>F</i> = 4.58; <i>p</i> = 0.033), favoring a greater sustained improvement in the CBT group. This corresponded to a moderate-to-large effect size of the Cohen <i>d</i> = 0.71 (95% CI –0.30 to 1.70) at the end of the study (14 weeks following the last ketamine infusion). In a subset of patients (<i>N</i> = 20) who underwent cognitive testing using the emotional N-back assessments before and after ketamine, ketamine responders showed improvement in the accuracy of emotional N-back (<i>t</i>[8] = 2.33; <i>p</i> &#x3c; 0.05) whereas nonresponders did not (<i>t</i>[10] &#x3c;1; <i>p</i> ns). <b><i>Conclusions:</i></b> This proof-of-concept study provides preliminary data indicating that CBT may sustain the antidepressant effects of ketamine in TRD. Further study and optimization of this treatment approach in well-powered clinical trials is recommended.

In general, ketamine infusions were tolerated well. The response and remission rates in this clinical sample were lower than those observed in some research protocols. The small number of patients who were treated on a maintenance schedule limits the conclusions that can be drawn regarding the long-term safety of ketamine; however, no long-term adverse effects were observed in this sample.

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Background: Prefrontal abnormalities in schizophrenia have consistently emerged from resting state and cognitive neuroimaging studies. However, these correlative findings require causal verification via combined imaging/stimulation approaches. To date, no interleaved transcranial magnetic stimulation and functional magnetic resonance imaging study (TMS fMRI) has probed putative prefrontal cortex abnormalities in schizophrenia. Objective: /Hypothesis: We hypothesized that subjects with schizophrenia would show significant hyperexcitability at the site of stimulation (BA9) and decreased interhemispheric functional connectivity. Methods: We enrolled 19 unmedicated subjects with schizophrenia and 22 controls. All subjects underwent brain imaging using a 3T MRI scanner with a SENSE coil. They also underwent a single TMS fMRI session involving motor threshold (rMT) determination, structural imaging, and a parametric TMS fMRI protocol with 10 Hz triplet pulses at 0, 80, 100 and 120% rMT. Scanning involved a surface MR coil optimized for bilateral prefrontal cortex image acquisition. Results: Of the original 41 enrolled subjects, 8 subjects with schizophrenia and 11 controls met full criteria for final data analyses. At equal TMS intensity, subjects with schizophrenia showed hyperexcitability in left BA9 (p ¼ 0.0157; max z-score ¼ 4.7) and neighboring BA46 (p ¼ 0.019; max z-score ¼ 4.47). Controls showed more contralateral functional connectivity between left BA9 and right BA9 through increased activation in right BA9 (p ¼ 0.02; max z-score ¼ 3.4). GM density in subjects with schizophrenia positively correlated with normalized prefrontal to motor cortex ratio of the corresponding distance from skull to cortex ratio (S-BA9/S-MC) (r ¼ 0.83, p ¼ 0.004). Conclusions: Subjects with schizophrenia showed hyperexcitability in left BA9 and impaired interhemispheric functional connectivity compared to controls. Interleaved TMS fMRI is a promising tool to investigate prefrontal dysfunction in schizophrenia.

Preliminary evidence reported here suggests that lower baseline BDNF may be associated with better clinical response to riluzole.