Treatment-Resistant Depression: An Update on Diagnosis and Management

Blunted amygdala activity is associated with depression severity in treatment-resistant depression

Up to 50% of individuals with major depressive disorder (MDD) do not recover after two antidepressant medication trials, and therefore meet the criteria for treatment-resistant depression (TRD). Mindfulness-based cognitive therapy (MBCT) is one promising treatment; however, the extent to which MBCT influences clinical outcomes relative to baseline neural activation remains unknown. In the present study we investigated baseline differences in amygdala activation between TRD patients and healthy controls (HCs), related amygdala activation to depression symptoms, and examined the impacts of MBCT and amygdala activation on longitudinal depression outcomes. At baseline, TRD patients (n = 80) and HCs (n = 37) participated in a functional magnetic resonance imaging task in which they identified either the emotion (affect labeling) or the gender (gender labeling) of faces, or passively viewed faces (observing). The TRD participants then completed eight weeks of MBCT or a health enhancement program (HEP). Relative to HCs, the TRD patients demonstrated less amygdala activation during affect labeling, and marginally less during gender labeling. Blunted amygdala activation in TRD patients during affect labeling was associated with greater depression severity. MBCT was associated with greater depression reductions than was HEP directly following treatment; however, at 52 weeks the treatment effect was not significant, and baseline amygdala activation across the task conditions predicted depression severity in both groups. TRD patients have blunted amygdala responses during affect labeling that are associated with greater concurrent depression. Furthermore, although MBCT produced greater short-term improvements in depression than did HEP, overall baseline amygdala reactivity was predictive of long-term clinical outcomes in both groups.

A Randomized Controlled Trial of Mindfulness-Based Cognitive Therapy for Treatment-Resistant Depression

BACKGROUND

Due to the clinical challenges of treatment-resistant depression (TRD), we evaluated the efficacy of mindfulness-based cognitive therapy (MBCT) relative to a structurally equivalent active comparison condition as adjuncts to treatment-as-usual (TAU) pharmacotherapy in TRD.

METHODS

This single-site, randomized controlled trial compared 8-week courses of MBCT and the Health Enhancement Program (HEP), comprising physical fitness, music therapy and nutritional education, as adjuncts to TAU pharmacotherapy for outpatient adults with TRD. The primary outcome was change in depression severity, measured by percent reduction in the total score on the 17-item Hamilton Depression Rating Scale (HAM-D17), with secondary depression indicators of treatment response and remission.

RESULTS

We enrolled 173 adults; mean length of a current depressive episode was 6.8 years (SD = 8.9). At the end of 8 weeks of treatment, a multivariate analysis showed that relative to the HEP condition, the MBCT condition was associated with a significantly greater mean percent reduction in the HAM-D17 (36.6 vs. 25.3%; p = 0.01) and a significantly higher rate of treatment responders (30.3 vs. 15.3%; p = 0.03). Although numerically superior for MBCT than for HEP, the rates of remission did not significantly differ between treatments (22.4 vs. 13.9%; p = 0.15). In these models, state anxiety, perceived stress and the presence of personality disorder had adverse effects on outcomes.

CONCLUSIONS

MBCT significantly decreased depression severity and improved treatment response rates at 8 weeks but not remission rates. MBCT appears to be a viable adjunct in the management of TRD.

Quetiapine extended release: adjunctive treatment in major depressive disorder

Quetiapine extended release (XR) is a once-daily oral formulation of the atypical antipsychotic quetiapine that is available for use as adjunctive therapy in major depressive disorder (MDD). Systemic quetiapine exposure after orally administered quetiapine XR is similar to that of quetiapine immediate release at the same dosage, although quetiapine XR is absorbed more slowly and plasma concentrations are more stable over time. In two 6-week, randomized, double-blind, placebo-controlled, multinational trials in patients with MDD with an inadequate response to antidepressants, quetiapine XR 300 mg/day adjunctive to antidepressant reduced depressive symptoms significantly more than antidepressant plus placebo, according to changes in Montgomery-Åsberg Depression Rating Scale (MADRS) total scores. In one trial, adjunctive quetiapine XR 150 mg/day also led to significantly greater reductions in MADRS total scores than antidepressant plus placebo. MDD response rates were significantly higher with adjunctive quetiapine XR 300 mg/day (but not 150 mg/day) than with antidepressant plus placebo. The numbers needed to treat to achieve an additional response over antidepressant plus placebo were 11-18 and 8-9 in the quetiapine XR 150 and 300 mg/day dosage groups, respectively. Treatment-emergent adverse events were mostly of mild to moderate severity; 1% of adjunctive quetiapine XR and 1.3% of antidepressant plus placebo recipients reported serious adverse events.