The neurobiology of treatment-resistant depression: A systematic review of neuroimaging studies.

Treatment-resistant depression (TRD) is a debilitating condition associated with higher medical costs, increased illness burden, and reduced quality of life compared to non-treatment-resistant major depressive disorder (MDD). The question arises whether TRD can be considered a distinct MDD sub-type based on neurobiological features. To answer this question we conducted a systematic review of neuroimaging studies investigating the neurobiological differences between TRD and non-TRD. Our main findings are that patients with TRD show 1) reduced functional connectivity (FC) within the default mode network (DMN), 2) reduced FC between components of the DMN and other brain areas, and 3) hyperactivity of DMN regions. In addition, aberrant activity and FC in the occipital lobe may play a role in TRD. The main limitations of most studies were related to inherent confounding factors for comparing TRD with non-TRD, such as differences in disease chronicity/severity and medication history. Future studies may use prospective longitudinal neuroimaging designs to delineate which effects are present in treatment-naive patients and which effects are the result of disease progression.

Comparative efficacy of imagery rehearsal therapy and prazosin in the treatment of trauma-related nightmares in adults: A meta-analysis of randomized controlled trials.

Pharmacological treatment with prazosin and psychological treatment with imagery rehearsal therapy (IRT) are the two main treatments of posttraumatic nightmares. The American Academy of Sleep Medicine task force recently listed IRT as the recommended treatment for trauma-related nightmares and changed the recommendation of prazosin to 'may be used'. This new recommendation was based on a single prazosin trial and not on a meta-analytic review of all available trials. The current meta-analysis aims to fill this gap in the literature. Eight studies on IRT and seven studies on prazosin (N = 1.078) were analyzed based on the random effects model. Relative to control groups, prazosin had a moderate to large effect on nightmare frequency (g = 0.61), posttraumatic stress symptoms (g = 0.81), and sleep quality (g = 0.85). IRT showed small to moderate effects on nightmare frequency (g = 0.51), posttraumatic symptoms (g = 0.31), and sleep quality (g = 0.51). No significant differences in effect were observed between prazosin and IRT on any of these outcomes (all p's > 0.10). It is concluded that downgrading the recommendation of prazosin may be a premature decision and that the aggregated results in this meta-analysis clearly show efficacy of both treatments.