Wang SM, et al. Chonnam Med J. 2018 May;54(2):101-112. https://doi.org/10.4068/cmj.2018.54.2.101

The precise mechanisms of pain perception and transmission in the central nervous system have not been fully elucidated. However, extensive data support a role for the monoamine neurotransmitters, serotonin and norepinephrine, in the modulation of pain. Experiments with animal models of pain indicate that noradrenergic interventions, and to a lesser extent serotonergic interventions, reduce pain-related behavior. This is supported by data from clinical trials in humans in which antidepressants have been shown to reduce pain and functional impairment in central and neuropathic pain conditions. These effects are particularly well-studied in trials with serotonin-norepinephrine reuptake inhibitors (SNRIs), which have provided a useful tool in the clinician's arsenal, particularly considering the limitations of other classes of pain medications such as opioids, anti-inflammatories, and anticonvulsants (i.e., limited efficacy, safety and tolerability issues). Moreover, painful physical symptoms are frequently comorbid with major psychiatric disorders such as major depressive disorder and anxiety disorders. This paper reviewed and summarized the rationale and potential role of SNRIs for the control of pain including clinical and preclinical background. Currently evidence does not definitely support a role of the SNRIs, while limited data propose a putative promise of SNRIs in the treatment of pain related disorders including fibromyalgia and depressed patients with multiple somatic complaints. More researches are warranted to generalize currently available preliminary evidences.

Pae CU. Psychiatry Investig. 2015 Jul;12(3):417-419. http://dx.doi.org/10.4306/pi.2015.12.3.417

Han C, et al. Psychiatry Investig. 2015 Jan;12(1):1-8. http://dx.doi.org/10.4306/pi.2015.12.1.1

Posttraumatic stress disorder (PTSD) is a prevalent and disabling mental illness. Small studies found atypical antipsychotics (AAs) to be beneficial in the treatment of patients with PTSD regardless of psychotic symptoms who are unresponsive to conventional pharmacological treatments such as serotonin selective reuptake inhibitors. This study reports the results of a meta-analysis of existing randomized, double-blind, placebo-controlled clinical trials (RCTs) of AAs as a monotherapy or augmentation therapy for the treatment of patients with PTSD. Seven RCTs were identified through extensive scans of databases, which included PubMed, MedLine, the National PTSD Center Pilots database, PsycINFO, Cochrane Central Register of Controlled Trials, and the Abstracts Library of the American Psychiatric Association with predefined inclusion criteria. Dichotomous and continuous measures were performed using a fixed effects model, heterogeneity was assessed, and subgroup analyses were done. Data from seven RCTs involving a total of 192 PTSD patients (102 randomized to AAs and 90 randomized to placebo) were analyzed. The results show that AAs may have a beneficial effect in the treatment of PTSD, as indicated by the changes from baseline in Clinician Administered PTSD Scale total scores [standardized mean difference (SMD)=−0.45, 95% confidence interval (CI) (−0.75, −0.14), P=0.004]. In addition, the overall SMD of the mean changes in the three Clinician Administered PTSD Scale subscores was statistically significant (P=0.007) between AAs and placebo groups, favoring AAs over placebo (SMD=−0.27, 95% CI=−0.47, −0.07). In particular, the symptom of ‘intrusion’ was mainly responsible for this significance. Clinical significance of the results, however, should be carefully interpreted and translated into clinical practice, given that the quality and availability of currently existing RCTs included in the analysis.