Major depressive disorder (MDD) is the leading cause of disability worldwide and is associated with high rates of suicide and medical comorbidities. Current antidepressant medications are suboptimal, as most MDD patients fail to achieve complete remission from symptoms. At present, clinicians are unable to predict which antidepressant is most effective for a particular patient, exposing patients to multiple medication trials and side effects. Since MDD’s etiology includes interactions between genes and environment, the epigenome is of interest for predictive utility and treatment monitoring. Epigenetic mechanisms of antidepressant medications are incompletely understood. Differences in epigenetic profiles may impact treatment response. A systematic literature search yielded 24 studies reporting the interaction between antidepressants and eight genes (BDNF, MAOA, SLC6A2, SLC6A4, HTR1A, HTR1B, IL6, IL11) and whole genome methylation. Methylation of certain sites within BDNF, SLC6A4, HTR1A, HTR1B, IL11, and the whole genome was predictive of antidepressant response. Comparing DNA methylation in patients during depressive episodes, during treatment, in remission, and after antidepressant cessation would help clarify the influence of antidepressant medications on DNA methylation. Individuals’ unique methylation profiles may be used clinically for personalization of antidepressant choice in the future.

The anterior cingulate cortex (ACC) is involved in emotion regulation and salience processing. Prior research has implicated ACC dysfunction in suicidal ideation (SI) and suicidal behavior. This study aimed to quantify ACC glutamatergic concentrations and to examine relationships with SI in a sample of healthy and depressed adolescents. Forty adolescents underwent clinical evaluation and proton magnetic resonance spectroscopy (¹H-MRS) at 3 T, utilizing a 2-dimensionalJ-averaged PRESS sequence sampling a medial pregenual ACC voxel. Cerebrospinal fluid-corrected ACC metabolite concentrations were compared between healthy control (HC,n = 16), depressed without SI (Dep/SI−,n = 13), and depressed with SI (Dep/SI+,n = 11) youth using general linear models covarying for age, sex, and psychotropic medication use. Relationships between ACC metabolites and continuous measures of SI were examined using multiple linear regressions. ROC analysis was used to determine the ability of glutamate+glutamine (Glx) and theN-acetylaspartate (NAA)/Glx ratio to discriminate Dep/SI− and Dep/SI+ adolescents. Dep/SI+ adolescents had higher Glx than Dep/SI− participants (p_adj = 0.012) and had lower NAA/Glx than both Dep/SI− (p_adj = 0.002) and HC adolescents (p_adj = 0.039). There were significant relationships between SI intensity and Glx (p_FDR = 0.026), SI severity and NAA/Glx (p_FDR = 0.012), and SI intensity and NAA/Glx (p_FDR = 0.004). ACC Glx and NAA/Glx discriminated Dep/SI− from Dep/SI+ participants. Uncoupled NAA−glutamatergic metabolism in the ACC may play a role in suicidal ideation and behavior. Longitudinal studies are needed to establish whether aberrant glutamatergic metabolism corresponds to acute or chronic suicide risk. Glutamatergic biomarkers may be promising targets for novel risk assessment and interventional strategies for suicidal ideation and behavior.

Purpose: Physician suicide rates are reportedly higher than those of the general population, but medical student suicide rates are not well studied. It is difficult to determine whether physician suicide rates can be predicted by medical student risk factors for suicide and difficult to identify those risk factors without knowing medical student suicide rates. The authors systematically reviewed the literature to collate data on medical student suicide rates. Method: The authors searched the PubMed, Web of Science, and Library of Congress databases for papers published in any language before November 11, 2017. They identified 3,429 papers; after the initial screening process, they assessed 82 full-text articles for eligibility. Twelve ultimately met the full inclusion criteria; meta-analysis was not possible. Data regarding medical student suicide numbers and rates were extracted and compared with contemporaneous general population suicide rates using public epidemiological data, when available. Results: Medical student suicide rates were infrequently reported in the historical and international literature, and data collection techniques were inconsistent. Generally, U.S. medical student suicide rates were lower than those of the contemporaneous general population. Proportionate mortality of medical students (number of deaths by a particular cause such as suicide divided by total number of deaths) was not reported in the literature. Conclusions: Gaps exist in knowledge of medical student suicide rates, risk factors, and targets for intervention. Significant barriers have impeded information collection. Yet, more comprehensive data collection is needed to understand suicide risk in this population and to implement and improve effective intervention strategies.

Post-traumatic stress disorder (PTSD) is an acquired psychiatric disorder with functionally impairing physiological and psychological symptoms following a traumatic exposure. Genetic, epigenetic, and environmental factors act together to determine both an individual’s susceptibility to PTSD and its clinical phenotype. In this literature review, we briefly review the candidate genes that have been implicated in the development and severity of the PTSD phenotype. We discuss the importance of the epigenetic regulation of these candidate genes. We review the general epigenetic mechanisms that are currently understood, with examples of each in the PTSD phenotype. Our focus then turns to studies that have examined PTSD in the context of comorbid psychiatric disorders or associated social and behavioral stressors. We examine the epigenetic variation in cases or models of PTSD with comorbid depressive disorders, anxiety disorders, psychotic disorders, and substance use disorders. We reviewed the literature that has explored epigenetic regulation in PTSD in adverse childhood experiences and suicide phenotypes. Finally, we review some of the information available from studies of the transgenerational transmission of epigenetic variation in maternal cases of PTSD. We discuss areas pertinent for future study to further elucidate the complex interactions between epigenetic modifications and this complex psychiatric disorder.