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Journal: European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology

175

Does it matter what we eat for our mental health? Accumulating data suggests that this may indeed be the case and that diet and nutrition are not only critical for human physiology and body composition, but also have significant effects on mood and mental wellbeing. While the determining factors of mental health are complex, increasing evidence indicates a strong association between a poor diet and the exacerbation of mood disorders, including anxiety and depression, as well as other neuropsychiatric conditions. There are common beliefs about the health effects of certain foods that are not supported by solid evidence and the scientific evidence demonstrating the unequivocal link between nutrition and mental health is only beginning to emerge. Current epidemiological data on nutrition and mental health do not provide information about causality or underlying mechanisms. Future studies should focus on elucidating mechanism. Randomized controlled trials should be of high quality, adequately powered and geared towards the advancement of knowledge from population-based observations towards personalized nutrition. Here, we provide an overview of the emerging field of nutritional psychiatry, exploring the scientific evidence exemplifying the importance of a well-balanced diet for mental health. We conclude that an experimental medicine approach and a mechanistic understanding is required to provide solid evidence on which future policies on diet and nutrition for mental health can be based.

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Stimulants and caffeine have been proposed for cognitive enhancement by healthy subjects. This study investigated whether performance in chess - a competitive mind game requiring highly complex cognitive skills - can be enhanced by methylphenidate, modafinil or caffeine. In a phase IV, randomized, double-blind, placebo-controlled trial, 39 male chess players received 2×200mg modafinil, 2×20mg methylphenidate, and 2×200mg caffeine or placebo in a 4×4 crossover design. They played twenty 15-minute games during two sessions against a chess program (Fritz 12; adapted to players' strength) and completed several neuropsychological tests. Marked substance effects were observed since all three substances significantly increased average reflection time per game compared to placebo resulting in a significantly increased number of games lost on time with all three treatments. Treatment effects on chess performance were not seen if all games (n=3059) were analysed. Only when controlling for game duration as well as when excluding those games lost on time, both modafinil and methylphenidate enhanced chess performance as demonstrated by significantly higher scores in the remaining 2876 games compared to placebo. In conjunction with results from neuropsychological testing we conclude that modifying effects of stimulants on complex cognitive tasks may in particular result from more reflective decision making processes. When not under time pressure, such effects may result in enhanced performance. Yet, under time constraints more reflective decision making may not improve or even have detrimental effects on complex task performance.

Concepts: Clinical trial, Neuropsychological test, Chess, Neurocognitive, Decision making, Neuropsychological assessment, Randomized controlled trial, Cognition

35

Alcohol dependence is associated with a dysregulated dopamine system modulating reward, craving and cognition. The monoamine stabilizer (-)-OSU6162 (OSU6162) can counteract both hyper- and hypo-dopaminergic states and we recently demonstrated that it attenuates alcohol-mediated behaviors in long-term drinking rats. The present Phase II exploratory human laboratory study investigated to our knowledge for the first time the effects of OSU6162 on cue- and priming-induced craving in alcohol dependent individuals. Fifty-six alcohol dependent individuals were randomized to a 14-day-treatment period of OSU6162 or placebo after their baseline impulsivity levels had been determined using the Stop Signal Task. On Day 15, participants were subjected to a laboratory alcohol craving test comprised of craving sessions induced by: i) active - alcohol specific cues, ii) neutral stimuli and iii) priming - intake of an alcoholic beverage (0.20g ethanol/kg bodyweight). Subjective ratings of alcohol craving were assessed using the shortened version of the Desire for Alcohol Questionnaire and visual analog scales (VAS). OSU6162 treatment had no significant effect on cue-induced alcohol craving, but significantly attenuated priming-induced craving. Exploratory analysis revealed that this effect was driven by the individuals with high baseline impulsivity. In addition, OSU6162 significantly blunted the subjective liking of the consumed alcohol (VAS). Although the present 14-day-treatment period, showed that OSU6162 was safe and well tolerated, this exploratory human laboratory study was not designed to evaluate the efficacy of OSU6162 to affect alcohol consumption. Thus a larger placebo-controlled efficacyclinical trial is needed to further investigate the potential of OSU6162 as a novel medication for alcohol dependence.

Concepts: Vodka, Beer, Alcohol abuse, Alcohol, Alcoholic beverage, Dopamine, Drinking culture, Alcoholism

30

In the last ten years, gabapentin and pregabalin have been becoming dispensed broadly and sold on black markets, thereby, exposing millions to potential side-effects. Meanwhile, several pharmacovigilance-databases have warned for potential abuse liabilities and overdose fatalities in association with both gabapentinoids. To evaluate their addiction risk in more detail, we conducted a systematic review on PubMed/Scopus and included 106 studies. We did not find convincing evidence of a vigorous addictive power of gabapentinoids which is primarily suggested from their limited rewarding properties, marginal notes on relapses, and the very few cases with gabapentinoid-related behavioral dependence symptoms (ICD-10) in patients without a prior abuse history (N=4). In support, there was no publication about people who sought treatment for the use of gabapentinoids. Pregabalin appeared to be somewhat more addictive than gabapentin regarding the magnitude of behavioral dependence symptoms, transitions from prescription to self-administration, and the durability of the self-administrations. The principal population at risk for addiction of gabapentinoids consists of patients with other current or past substance use disorders (SUD), mostly opioid and multi-drug users, who preferred pregabalin. Pure overdoses of gabapentinoids appeared to be relative safe but can become lethal (pregabalin > gabapentin) in mixture with other psychoactive drugs, especially opioids again and sedatives. Based upon these results, we compared the addiction risks of gabapentin and pregabalin with those of traditional psychoactive substances and recommend that in patients with a history of SUD, gabapentinoids should be avoided or if indispensable, administered with caution by using a strict therapeutic and prescription monitoring.

Concepts: Drug, Psychoactive drug, Recreational drug use, Nicotine, Drug addiction, Drug rehabilitation, Opioid, Morphine

29

This study identified individuals ever dispensed a selective serotonin reuptake inhibitor (SSRI) aged 15-60 years during 2006-2013, using Swedish national registers. The outcome was violent crime conviction. The main statistical analyses assessed risks of violent crime during periods on compared to off SSRI treatment within individuals. Further analyses investigated risk over time in relation to treatment initiation and discontinuation. The study identified 785,337 individuals (64.2% female), experiencing 32,203 violent crimes in 5,707,293 person-years. Between-individual analyses found statistically significantly elevated Hazard Ratios (HRs) overall (HR = 1.10), and in 15-24 and 25-34 year-olds (HR = 1.19 and 1.16), but non-significant HRs in 35-44 and 45-60-year-olds (HR = 1.02 and 1.04). In within-individual analyses, where 2.6% of SSRI users were informative, hazards were elevated overall (HR = 1.26, 95% CI = 1.19, 1.34), and across age groups (HR of 1.35 [95% CI = 1.19, 1.54] in 25-34-year-olds to 1.15 [95% CI = 0.99, 1.33] in 35-44-year-olds). In the overall cohort, the within-individual HRs were significantly elevated throughout treatment (HRs of 1.24 to 1.35) and for up to 12 weeks post-discontinuation (HRs of 1.37 and 1.20). While questions on causality remain, these results indicate that there may be an increased risk of violent crime during SSRI treatment in a small group of individuals. It may persist throughout medicated periods, across age groups, and after treatment discontinuation. Further confirmation is needed from studies with different designs, and clinical focus should be on high-risk individuals, as a majority of SSRI-users (around 97% in our cohort) will not commit violent crimes.

27

We carried out dynamic [18F]fallypride PET scans to measure cerebral dopamine D2/3 receptor availability in a 23-year old patient experiencing a severe withdrawal syndrome upon voluntary abstinence from “Spice”, a pre-packaged herbal smoking thought to contain synthetic cannabinoids. Upon admission to the clinic, the patient experienced craving, affective symptoms and a range of somatic complaints, which resolved after several days' monitored abstinence. PET scans were performed on the day of admission, and one week later. Estimates of [18F]fallypride binding potential (BPND) were obtained in striatal and extrastriatal brain regions, and compared to results of age-matched healthy control subjects. Upon admission, [18F]fallypride BPND was reduced by 20% in the patient’s striatum and also in extra-striatal regions. During short-term follow-up upon detoxification, the BPND increased to normal values. This study shows substantial short-term alterations of dopamine D2/3 receptor availability in a patient before and after acute detoxification from “Spice Gold”, thus providing first evidence of reversible effects on dopamine receptors of heavy use of a herbal smoking blend.

Concepts: Ventral tegmental area, HU-210, Striatum, Cannabinoid, Dopamine, Second messenger system, Nicotine, Addiction

27

Single nucleotide polymorphisms (SNPs) in 3' untranslated regions (3' UTRs) of genes may affect miRNA binding to messenger RNA and contribute to the risk of disease. Whether the SNPs that modify miRNA binding in the 3' UTR are involved in schizophrenia-related genes remains unclear. We selected 803 SNPs from the 3' UTRs of 425 candidate genes for schizophrenia. The potential target SNPs were recognized by Gibbs free energy of miRNA binding. Some SNPs were associated in the literature with schizophrenia or other related neurological diseases. A case-control study of nine SNPs not previously reported as significant in any disease was carried out in a Chinese-Han cohort. We found that rs3219151 (C>T, GABRA6) showed significant decreased risk for schizophrenia (OR=0.8121, p=0.008, p(adjust)=0.03). Further, two putative target SNPs, rs165599 (COMT) and rs10759 (RGS4) reported in several references previously, were selected for analysis by luciferase assay to determine their modification to miRNA binding. We found that miR-124 showed significantly repressed 3' UTR binding to RGS4 mRNA from the rs10759-C allele (p<0.05). Our results suggest that rs3219151 of GABRA6 was associated significantly to decrease the risk of schizophrenia, rs10759 (RGS4) was possible to increase the risk of schizophrenia by miRNA altering the binding of miRNAs to their targets influencing susceptibility to schizophrenia.

Concepts: Genetics, Five prime untranslated region, Three prime untranslated region, Gene expression, MicroRNA, Messenger RNA, DNA, RNA

26

The extent to which clinicians adhere to international guidelines for the pharmacological management of obsessive-compulsive disorder (OCD) is unknown. We aimed to comprehensively map the patterns of prescription of psychotropic drugs for OCD patients (adults and children) at the Swedish national level and to compare these prescription patterns to best-practice recommendations in international guidelines. We linked the Swedish National Patient Register and the Swedish Prescribed Drug Register, which includes a record for all medications prescribed and dispensed in Sweden since July 2005. Of all active OCD cases in the Swedish National Patient Register between July 1st, 2005, and December 31st 2008 (N=10,523), 85% received at least one psychotropic drug. Most of the medicated adults and children with OCD (88%) received serotonin reuptake inhibitors (SRIs). Of all adults and children prescribed SRIs, 16% received sub-optimal doses. An additional 12% of all medicated patients were prescribed drugs that never included an SRI. Approximately 75% of the patients on SRIs received additional drugs (67% anxiolytics/hypnotics, 27% antipsychotics, 17% serotonin and norepinephrine reuptake inhibitors, 24% other antidepressants). Twelve percent of all medicated patients were at least ‘regular’ users, and 3% ‘heavy’ users of benzodiazepines. We also observed important variations in prescription practices according to patient’s gender, age, and comorbidity status. We conclude that a substantial number of OCD patients might benefit from changes in their prescriptions. Dissemination of best-practice prescription guidelines for OCD is a major educational goal for the future. Monitoring of these prescription patterns over time is warranted.

Concepts: Fluvoxamine, Opioid, Tricyclic antidepressant, Recreational drug use, Antidepressant, Drug, Pharmacology, Selective serotonin reuptake inhibitor

23

Both positive and negative (null or neutral) results are essential for the progress of science and its self-correcting nature. However, there is general reluctance to publish negative results, and this may be due a range of factors (e.g., the widely held perception that negative results are more difficult to publish, the preference to publish positive findings that are more likely to generate citations and funding for additional research). It is particularly challenging to disclose negative results that are not consistent with previously published positive data, especially if the initial publication appeared in a high impact journal. Ideally, there should be both incentives and support to reduce the costs associated with investing efforts into preparing publications with negative results. We describe here a set of criteria that can help scientists, reviewers and editors to publish technically sound, scientifically high-impact negative (or null) results originating from rigorously designed and executed studies. Proposed criteria emphasize the importance of collaborative efforts and communication among scientists (also including the authors of original publications with positive results).

23

Azapirones, which are serotonin1A (5-HT1A) receptor partial agonists, have been used as an adjunctive treatment for schizophrenia with mixed results. This is a meta-analysis of the efficacy and tolerability of azapirones for schizophrenia based on randomized, double-blind, placebo-controlled trials (RCTs). English and Chinese databases were systematically and independently searched by two investigators. Data were extracted and analyzed using the RevMan software (version 5.3). Seven RCTs (n = 368) of azapirones (buspirone in 6 RCTs and tandospirone in 1 RCT) were identified and analyzed. Only adjunctive buspirone outperformed placebo regarding total psychopathology [standardized mean difference: -1.03 (95% confidence interval (CI): -1.91, -0.15), P = 0.02; I2 = 92%], but the significance disappeared in sensitivity analysis after removing two outlying studies, and in 10 of the 12 subgroup analyses. In 5 RCTs examining neurocognitive function of azapirones, only 2 RCTs found the superiority of buspirone in improving attention/speeded motor performance, verbal and performance intelligence. Adjunctive buspirone outperformed placebo regarding extrapyramidal symptoms [SMD:-0.51, (95%CI: -0.99, -0.02), P = 0.04; I2 = 0%]. Similar rates of discontinuation [risk ratio:1.06 (95%CI:0.54, 2.07), P = 0.86, I2 = 0%] and adverse drug reactions were found between both groups. Adjunctive buspirone and tandospirone failed to show efficacy for psychotic symptoms, but adjunctive buspirone may be associated with improvement in extrapyramidal symptoms and cognitive deficits in schizophrenia. Due to the preliminary nature of this meta-analysis, larger sample size and higher quality RCTs are needed to confirm these finding.

Concepts: Antipsychotic, Sample size, Tandospirone, Statistical hypothesis testing, Azapirone, Agonist, Adverse drug reaction, Buspirone