Victoria S. Marshe

Genetic Similarities between Compulsive Overeating and Addiction Phenotypes: A Case for "Food Addiction"?

There exists a continuous spectrum of overeating, where at the extremes there are casual overindulgences and at the other a ‘pathological’ drive to consume palatable foods. It has been proposed that pathological eating behaviors may be the result of addictive appetitive behavior and loss of ability to regulate the consumption of highly processed foods containing refined carbohydrates, fats, salt, and caffeine. In this review, we highlight the genetic similarities underlying substance addiction phenotypes and overeating compulsions seen in individuals with binge eating disorder. We relate these similarities to findings from neuroimaging studies on reward processing and clinical diagnostic criteria based on addiction phenotypes. The abundance of similarities between compulsive overeating and substance addictions puts forth a case for a ‘food addiction’ phenotype as a valid, diagnosable disorder.

The microbiome-gut-brain axis: implications for schizophrenia and antipsychotic induced weight gain

With the emergence of knowledge implicating the human gut microbiome in the development and regulation of several physiological systems, evidence has accumulated to suggest a role for the gut microbiome in psychiatric conditions and drug response. A complex relationship between the enteric nervous system, the gut microbiota and the central nervous system has been described which allows for the microbiota to influence and respond to a variety of behaviors and psychiatric conditions. Additionally, the use of pharmaceuticals may interact with and alter the microbiota to potentially contribute to adverse effects of the drug. The gut microbiota has been described in several psychiatric disorders including depression and anxiety, but only a few reports have discussed the role of the microbiome in schizophrenia. The following review examines the evidence surrounding the gut microbiota in behavior and psychiatric illness, the role of the microbiota in schizophrenia and the potential for antipsychotics to alter the gut microbiota and promote adverse metabolic events.

Genetic variation in IL-1β, IL-2, IL-6, TSPO and BDNF and response to duloxetine or placebo treatment in major depressive disorder.

AIM This study investigated polymorphisms of five inflammatory-related genes for association with duloxetine and placebo response in patients with major depression. PATIENTS & METHODS Twenty SNPs in IL-1β, IL-2, IL-6, TSPO and BDNF were genotyped in major depressive disorder patients treated with either duloxetine (n = 215) or placebo (n = 235) for up to 8 weeks. Treatment response was measured with the Montgomery-Åsberg Depression Rating Scale. RESULTS IL-6 variants rs2066992 and rs10242595 were nominally associated with response to duloxetine (p = 0.047 and p = 0.028, respectively). Notably, the variant rs2066992 was also associated with placebo response (p = 0.026). However, none of our results remained significant after correction for multiple testing. CONCLUSION Our findings tentatively suggest that IL-6 variants play a role in duloxetine and placebo response, which warrants further investigation.

The Effects of Video Games on Cognition and Brain Structure: Potential Implications for Neuropsychiatric Disorders

Video games are now a ubiquitous form of entertainment that has occasionally attracted negative attention. Video games have also been used to test cognitive function, as therapeutic interventions for neuropsychiatric disorders, and to explore mechanisms of experience-dependent structural brain changes. Here, we review current research on video games published from January 2011 to April 2014 with a focus on studies relating to mental health, cognition, and brain imaging. Overall, there is evidence that specific types of video games can alter brain structure or improve certain aspects of cognitive functioning. Video games can also be useful as neuropsychological assessment tools. While research in this area is still at a very early stage, there are interesting results that encourage further work in this field, and hold promise for utilizing this technology as a powerful therapeutic and experimental tool.

Molecular mechanisms in lithium-associated renal disease: a systematic review

PurposeLithium is an essential treatment in bipolar disorder and treatment-resistant depression; however, its use has been limited by concerns regarding its renal adverse effects. An improved understanding of potential molecular mechanisms can help develop prevention and treatment strategies for lithium-associated renal disease.MethodsWe conducted a systematic literature search using MEDLINE, Embase, and PsychINFO including English-language original research articles published prior to November 2015 that specifically investigated lithium’s effects on nephrogenic diabetes insipidus (NDI) and chronic kidney disease (CKD), using molecular markers.ResultsFrom a total of 3510 records, 71 pre-clinical studies and two relevant clinical studies were identified. Molecular alterations were reported in calcium signaling, inositol monophosphate, extracellular-regulated, prostaglandin, sodium/solute transport, G-protein-coupled receptors, nitric oxide, vasopressin/aquaporin, and inflammation-related pathways in lithium-associated renal disease. The majority of studies found that these mechanisms were implicated in NDI, while few studies had examined CKD.DiscussionFuture studies will have to focus on (1) validating the present findings in human subjects and (2) examining CKD, which is the most clinically relevant lithium-associated renal effect. This will improve our understanding of lithium’s biological effects, as well as inform a personalized medicine approach, which could lead to safer lithium prescribing and less renal adverse events.

Norepinephrine Transporter Gene Variants and Remission From Depression With Venlafaxine Treatment in Older Adults

OBJECTIVE The primary objective of this study was to investigate five putatively functional variants of the norepinephrine transporter (SLC6A2, NET) and serotonin transporter (SLC6A4, SERT) genes and remission in depressed older adults treated with venlafaxine. A secondary objective was to analyze 17 other variants in serotonergic system genes (HTR1A, HTR2A, HTR1B, HTR2C, TPH1, TPH2) potentially involved in the mechanism of action of venlafaxine. METHOD The sample included 350 adults age 60 or older with DSM-IV-defined major depressive disorder and a score of at least 15 on the Montgomery-Åsberg Depression Rating Scale (MADRS). Participants received protocolized treatment with open-label venlafaxine, up to 300 mg/day for approximately 12 weeks, as part of a three-site clinical trial. Each individual was genotyped for 22 polymorphisms in eight genes, which were tested for association with venlafaxine remission (a MADRS score ≤10) and changes in MADRS score during treatment. RESULTS After adjusting for multiple comparisons, NET variant rs2242446 (T-182C) was significantly associated with remission (odds ratio=1.66, 95% CI=1.13, 2.42). Individuals with the rs2242446 C/C genotype were more likely to remit (73.1%) than those with either the C/T (51.8%) or the T/T genotype (47.3%). Individuals with the C/C genotype also had a shorter time to remission than those with the C/T or T/T genotypes and had a greater percentage change in MADRS score from baseline to end of treatment (up to week 12). CONCLUSIONS NET rs2242446/T-182C may serve as a biomarker to predict the likelihood of remission with venlafaxine in older adults with major depression. These findings may help to optimize antidepressant outcomes in older adults.

The Complex Relationship between Antipsychotic-Induced Weight Gain and Therapeutic Benefits: A Systematic Review and Implications for Treatment

Background: Antipsychotic-induced weight gain (AIWG) and other adverse metabolic effects represent serious side effects faced by many patients with psychosis that can lead to numerous comorbidities and which reduce the lifespan. While the pathophysiology of AIWG remains poorly understood, numerous studies have reported a positive association between AIWG and the therapeutic benefit of antipsychotic medications. Objectives: To review the literature to (1) determine if AIWG is consistently associated with therapeutic benefit and (2) investigate which variables may mediate such an association. Data Sources: MEDLINE, Google Scholar, Cochrane Database and PsycINFO databases were searched for articles containing all the following exploded MESH terms: schizophrenia [AND] antipsychotic agents/neuroleptics [AND] (weight gain [OR] lipids [OR] insulin [OR] leptin) [AND] treatment outcome. Results were limited to full-text, English journal articles. Results: Our literature search uncovered 31 independent studies which investigated an AIWG-therapeutic benefit association with a total of 6063 enrolled individuals diagnosed with schizophrenia or another serious mental illness receiving antipsychotic medications. Twenty-two studies found a positive association while, 10 studies found no association and one study reported a negative association. Study variables including medication compliance, sex, ethnicity, or prior antipsychotic exposure did not appear to consistently affect the AIWG-therapeutic benefit relationship. In contrast, there was some evidence that controlling for baseline BMI/psychopathology, duration of treatment and specific agent studied [i.e., olanzapine (OLZ) or clozapine (CLZ)] strengthened the relationship between AIWG and therapeutic benefit. Limitations: There were limitations of the reviewed studies in that many had small sample sizes, and/or were retrospective. The heterogeneity of the studies also made comparisons difficult and publication bias was not controlled for. Conclusions: An AIWG-therapeutic benefit association may exist and is most likely to be observed in OLZ and CLZ-treated patients. The clinical meaningfulness of this association remains unclear and weight gain and other metabolic comorbidities should be identified and treated to the same targets as the general population. Further research should continue to explore the links between therapeutic benefit and metabolic health with emphasis on both pre-clinical work and well-designed prospective clinical trials examining metabolic parameters associated, but also occurring independently to AIWG.

Childhood Abuse History in Depression Predicts Better Response to Antidepressants with Higher Serotonin Transporter Affinity: A Pilot Investigation

Objectives: Childhood abuse is a powerful prognostic indicator in adults with major depressive disorder (MDD) and is associated with numerous biological risk factors for depression. The purpose of this investigation was to explore if antidepressant medication affinity for the serotonin transporter moderates the association between childhood abuse and treatment response. Methods: Our sample included 52 outpatients with MDD who had received up to 26 weeks of pharmacotherapy, stratifying antidepressant medications with a high versus a low affinity for the serotonin transporter. Patients completed the Hamilton Rating Scale for Depression, Beck Depression Inventory II, Home Environment Questionnaire, and Ontario Health Supplement: Child Abuse and Trauma Scale to assess depression and childhood abuse. Results: Medication class moderated the link between 3 indices of childhood abuse and treatment response such that higher levels of childhood abuse were associated with higher levels of depression severity after treatment only in those patients receiving antidepressant medications with a weak affinity for the serotonin transporter. Conclusions: This pilot study suggested that prolonged exposure to stress during childhood may result in biological vulnerabilities for depression, which may in turn be differentially targeted by pharmacological agents which target serotonin to a greater or lesser degree.

C-reactive protein and cardiovascular risk in bipolar disorder patients: A systematic review

OBJECTIVES New research is revealing a strong association between inflammatory markers with bipolar disorder (BD), potentially due to the high prevalence of cardiovascular disease and cardiovascular risk factors in BD. We aimed to synthesize the literature examining the association between the clinically most relevant inflammatory marker, C-reactive protein (CRP) and cardiovascular disease and cardiovascular risk factors in patients with BD. METHODS MEDLINE, Embase and PsychInfo were systematically searched for all relevant English language articles published prior to April 2017. Articles were included if they examined the association between CRP and cardiovascular risk factors/disease in BD. RESULTS Fifteen relevant articles were retrieved. Studies were mostly cross-sectional and heterogeneous in the cardiovascular risk factors investigated. Overall, elevated CRP was associated with increased risk of metabolic syndrome, elevated body mass index, higher waist circumference, and obesity. CRP was inconsistently associated with elevated fasting glucose, insulin levels, serum triglycerides, total cholesterol levels, and low high density lipoprotein (HDL) levels. Atypical antipsychotic use may mediate some of these effects. No study examined CRPs association with actual cardiovascular disease (e.g. coronary artery disease) in BD. CONCLUSIONS In BD, CRP is associated with increases in several cardiovascular risk factors, suggesting that systemic inflammation could be a shared driving force for both outcomes of BD and cardiovascular risk. Further longitudinal research is needed in this area to verify causality, including an examination of actual cardiovascular disease. Non-pharmacological and pharmacological treatments with anti-inflammatory effects should also be investigated, particularly in patients with increased CRP, for their potential to reduce cardiovascular risk in BD.