The efficacy of lamotrigine in bipolar disorder: A systematic review and meta-analysis.

OBJECTIVE: To provide up-to-date clinical guidance on the efficacy of lamotrigine in bipolar disorder (BD). METHODS: Eligible studies were identified during a systematic literature search according to PRISMA-guidelines. We included randomized controlled trials (RCTs) and cohort studies that quantitatively assessed lamotrigine's efficacy in BD. We divided the included studies into three groups: 1. acute treatment of depression, 2. acute treatment of mania and hypomania, and 3. maintenance treatment. Analyses were stratified by control group (placebo vs active comparator) and treatment strategy (monotherapy vs add-on treatment). RESULTS: We included 20 RCTs (n = 1166 lamotrigine users) and 20 cohort studies (n = 11,141 lamotrigine users). Twenty-four of these studies were included in meta-analyses. During depressive episodes, greater decreases in depressive symptomatology were associated with initiation of lamotrigine as add-on treatment than with placebo (SMD -0.30 [95% CI = -0.51, -0.10], df = 3, p = 0.004). Decreases in depressive symptomatology did not differ significantly between lamotrigine and the active comparator (SMD -0.28 [95% CI = -1.06, 0.50], df = 3, p = 0.488). As a maintenance treatment, lamotrigine was associated with a significantly lower relapse/recurrence rate than placebo (risk ratio (RR) 0.84 [95% CI = 0.71, 0.99], df = 2, p = 0.037). Relapse/recurrence rates did not differ significantly between lamotrigine and lithium (RR 1.06 [95% CI = 0.89, 1.25], df = 2, p = 0.513). A qualitative assessment of high-quality register-based studies found that lamotrigine was associated with lower hospital admission rates than other commonly used treatment regimes. CONCLUSIONS: There is substantial evidence for the efficacy of lamotrigine in BD, specifically as add-on treatment during acute depressive episodes and as maintenance treatment for preventing relapse and recurrence.

No association between anti-thyroidperoxidase antibodies and bipolar disorder: a study in the Dutch Bipolar Cohort and a meta-analysis.

BACKGROUND: Thyroid autoimmunity has been associated with bipolar disorder (BD). However, results from previous studies on the seroprevalence of anti-thyroid peroxidase antibodies (TPO-abs) in BD are inconsistent. OBJECTIVES: The aim of the present study is to investigate whether the seroprevalence and titer levels of TPO-abs are related to BD. METHOD: TPO-abs were measured in plasma samples of 760 patients with bipolar disorder, 261 first-degree relatives and 363 controls by enzyme-linked immunosorbent assay (ELISA). To address methodological limitations of previous studies, we assessed clinical characteristics with several (self-reported) questionnaires to investigate whether TPO-abs positivity is related to particular clinical subgroups of BD patients. We performed an additional meta-analysis of seroprevalences of TPO-abs in BD patients including data from present and previous studies. RESULTS: Seroprevalence or titer levels of TPO-abs did not significantly differ between patients with BD, their first-degree relatives, and controls. In BD patients, the prevalence of TPO-abs was unrelated to specific clinical factors, including lithium use. Our meta-analysis of twelve studies showed an overall odds ratio of 1.3 (CI 95 %: 0.7-2.3; p = 0.30), reaffirming the absence of an association of BD with TPO-abs. CONCLUSIONS: In the largest study of TPO-abs in BD to date, our findings indicate that TPO-abs are not associated with (the risk for) bipolar disorder.

The Role of Stressful Parenting and Mineralocorticoid Receptor Haplotypes on Social Development During Adolescence and Young Adulthood.

The development of social behavior could be affected by stressful parenting. The mineralocorticoid receptor, one of the two main receptors for the stress hormone cortisol, plays a vital role in adequate responses to stress. Therefore, the effects of stressful parenting on social development (i.e., empathic concern, perspective taking and prosocial behavior) may be moderated by functional genetic variation in mineralocorticoid receptor haplotypes (a combination of alleles). A group of 343 adolescents (44.3% females) was followed from the age of 13 until 24 years. Growth curve analyses showed lower levels of prosocial behaviors and a slower increase in empathic concern and perspective taking in adolescents who reported more stressful parenting. In contrast, relatively higher levels of prosocial behavior, empathic concern and perspective taking were present in combination with stress resilient mineralocorticoid receptor haplotypes. Despite sex differences in social development with earlier social development for girls, no consistent sex differences were found with regard to mineralocorticoid receptor haplotypes. The current study showed that genetic variation in mineralocorticoid receptor impacts the social development during adolescence and young adulthood.

Genetic vulnerability to DUSP22 promoter hypermethylation is involved in the relation between in utero famine exposure and schizophrenia.

Epigenetic changes may account for the doubled risk to develop schizophrenia in individuals exposed to famine in utero. We therefore investigated DNA methylation in a unique sample of patients and healthy individuals conceived during the great famine in China. Subsequently, we examined two case-control samples without famine exposure in whole blood and brain tissue. To shed light on the causality of the relation between famine exposure and DNA methylation, we exposed human fibroblasts to nutritional deprivation. In the famine-exposed schizophrenia patients, we found significant hypermethylation of the dual specificity phosphatase 22 (DUSP22) gene promoter (Chr6:291687-293285) (N = 153, p = 0.01). In this sample, DUSP22 methylation was also significantly higher in patients independent of famine exposure (p = 0.025), suggesting that hypermethylation of DUSP22 is also more generally involved in schizophrenia risk. Similarly, DUSP22 methylation was also higher in two separate case-control samples not exposed to famine using DNA from whole blood (N = 64, p = 0.03) and postmortem brains (N = 214, p = 0.007). DUSP22 methylation showed strong genetic regulation across chromosomes by a region on chromosome 16 which was consistent with new 3D genome interaction data. The presence of a direct link between famine and DUSP22 transcription was supported by data from cultured human fibroblasts that showed increased methylation (p = 0.048) and expression (p = 0.019) in response to nutritional deprivation (N = 10). These results highlight an epigenetic locus that is genetically regulated across chromosomes and that is involved in the response to early-life exposure to famine and that is relevant for a major psychiatric disorder.

Longitudinal analyses of the DNA methylome in deployed military servicemen identify susceptibility loci for post-traumatic stress disorder.

In order to determine the impact of the epigenetic response to traumatic stress on post-traumatic stress disorder (PTSD), this study examined longitudinal changes of genome-wide blood DNA methylation profiles in relation to the development of PTSD symptoms in two prospective military cohorts (one discovery and one replication data set). In the first cohort consisting of male Dutch military servicemen (n=93), the emergence of PTSD symptoms over a deployment period to a combat zone was significantly associated with alterations in DNA methylation levels at 17 genomic positions and 12 genomic regions. Evidence for mediation of the relation between combat trauma and PTSD symptoms by longitudinal changes in DNA methylation was observed at several positions and regions. Bioinformatic analyses of the reported associations identified significant enrichment in several pathways relevant for symptoms of PTSD. Targeted analyses of the significant findings from the discovery sample in an independent prospective cohort of male US marines (n=98) replicated the observed relation between decreases in DNA methylation levels and PTSD symptoms at genomic regions in ZFP57, RNF39 and HIST1H2APS2. Together, our study pinpoints three novel genomic regions where longitudinal decreases in DNA methylation across the period of exposure to combat trauma marks susceptibility for PTSD.

Longitudinal changes in glucocorticoid receptor exon 1F methylation and psychopathology after military deployment.

Several cross-sectional studies have demonstrated the relevance of DNA methylation of the glucocorticoid receptor exon 1F region (GR-1F) for trauma-related psychopathology. We conducted a longitudinal study to examine GR-1F methylation changes over time in relation to trauma exposure and the development of post-deployment psychopathology. GR-1F methylation (52 loci) was quantified using pyrosequencing in whole blood of 92 military men 1 month before and 6 months after a 4-month deployment period to Afghanistan. GR-1F methylation overall (mean methylation and the number of methylated loci) and functional methylation (methylation at loci associated with GR exon 1F expression) measures were examined. We first investigated the effect of exposure to potentially traumatic events during deployment on these measures. Subsequently, changes in GR-1F methylation were related to changes in mental health problems (total Symptom Checklist-90 score) and posttraumatic stress disorder (PTSD) symptoms (Self-Report Inventory for PTSD). Trauma exposure during deployment was associated with an increase in all methylation measures, but development of mental health problems 6 months after deployment was only significantly associated with an increased functional methylation. Emergence of post-deployment PTSD symptoms was not related to increased functional methylation over time. Pre-deployment methylation levels did not predict post-deployment psychopathology. To our knowledge, this is the first study to prospectively demonstrate trauma-related increases in GR-1F methylation, and it shows that only increases at specific functionally relevant sites predispose for post-deployment psychopathology.

Genome-wide association study of borderline personality disorder reveals genetic overlap with bipolar disorder, major depression and schizophrenia.

Borderline personality disorder (BOR) is determined by environmental and genetic factors, and characterized by affective instability and impulsivity, diagnostic symptoms also observed in manic phases of bipolar disorder (BIP). Up to 20% of BIP patients show comorbidity with BOR. This report describes the first case-control genome-wide association study (GWAS) of BOR, performed in one of the largest BOR patient samples worldwide. The focus of our analysis was (i) to detect genes and gene sets involved in BOR and (ii) to investigate the genetic overlap with BIP. As there is considerable genetic overlap between BIP, major depression (MDD) and schizophrenia (SCZ) and a high comorbidity of BOR and MDD, we also analyzed the genetic overlap of BOR with SCZ and MDD. GWAS, gene-based tests and gene-set analyses were performed in 998 BOR patients and 1545 controls. Linkage disequilibrium score regression was used to detect the genetic overlap between BOR and these disorders. Single marker analysis revealed no significant association after correction for multiple testing. Gene-based analysis yielded two significant genes: DPYD (P=4.42 × 10-7) and PKP4 (P=8.67 × 10-7); and gene-set analysis yielded a significant finding for exocytosis (GO:0006887, PFDR=0.019; FDR, false discovery rate). Prior studies have implicated DPYD, PKP4 and exocytosis in BIP and SCZ. The most notable finding of the present study was the genetic overlap of BOR with BIP (rg=0.28 [P=2.99 × 10-3]), SCZ (rg=0.34 [P=4.37 × 10-5]) and MDD (rg=0.57 [P=1.04 × 10-3]). We believe our study is the first to demonstrate that BOR overlaps with BIP, MDD and SCZ on the genetic level. Whether this is confined to transdiagnostic clinical symptoms should be examined in future studies.

Acute stress effects on GABA and glutamate levels in the prefrontal cortex: A 7T 1H magnetic resonance spectroscopy study.

There is ample evidence that the inhibitory GABA and the excitatory glutamate system are essential for an adequate response to stress. Both GABAergic and glutamatergic brain circuits modulate hypothalamus-pituitary-adrenal (HPA)-axis activity, and stress in turn affects glutamate and GABA levels in the rodent brain. However, studies examining stress-induced GABA and glutamate levels in the human brain are scarce. Therefore, we investigated the influence of acute psychosocial stress (using the Trier Social Stress Test) on glutamate and GABA levels in the medial prefrontal cortex of 29 healthy male individuals using 7 Tesla proton magnetic resonance spectroscopy. In vivo GABA and glutamate levels were measured before and 30 min after exposure to either the stress or the control condition. We found no associations between psychosocial stress or cortisol stress reactivity and changes over time in medial prefrontal glutamate and GABA levels. GABA and glutamate levels over time were significantly correlated in the control condition but not in the stress condition, suggesting that very subtle differential effects of stress on GABA and glutamate across individuals may occur. However, overall, acute psychosocial stress does not appear to affect in vivo medial prefrontal GABA and glutamate levels, at least this is not detectable with current practice 1H-MRS.

Educational achievement in psychiatric patients and their siblings: a register-based study in 30 000 individuals in The Netherlands.

BACKGROUND: Poor educational achievement is associated with a range of psychiatric disorders. Several studies suggest that this underperformance is due to cognitive deficits that commence before disease onset and reflect a genetic risk for this disorder. However, the specificity and the familial contribution of this cognitive deficit are not clear. We analysed lifetime educational achievement of psychiatric patients diagnosed with schizophrenia, bipolar or depressive disorder and their unaffected siblings. METHOD: In a register-based case-control study, 1561 patients with schizophrenia, 813 patients with bipolar disorder, 8112 patients with depression, and their siblings were each matched with eight population controls. Patients, siblings and controls were compared on the highest educational stream they completed. RESULTS: Lower educational achievement was present in schizophrenia patients from primary school onwards [completing primary school: odds ratio (OR) 0.69; completing secondary school: OR 0.69; completing academic education: OR 0.46], compared to patients with bipolar disorder or depression. Siblings of schizophrenia, bipolar or depressed patients showed no underachievement at primary or secondary school, but siblings of schizophrenia patients as well as siblings of depressed patients were less successful in their educational achievement after secondary school (completing academic education, schizophrenia siblings: OR 0.90; depressive disorder siblings: OR 0.91). CONCLUSIONS: Educational underachievement from primary school onwards is specifically related to schizophrenia and not to bipolar disorder or depression. Moreover, it appears to be a harbinger of the illness, since it is not found in their siblings. These results add to evidence that early cognitive deficits are a distinct feature of the schizophrenia phenotype.

High educational performance is a distinctive feature of bipolar disorder: a study on cognition in bipolar disorder, schizophrenia patients, relatives and controls.

BACKGROUND: Schizophrenia is associated with lower intelligence and poor educational performance relative to the general population. This is, to a lesser degree, also found in first-degree relatives of schizophrenia patients. It is unclear whether bipolar disorder I (BD-I) patients and their relatives have similar lower intellectual and educational performance as that observed in schizophrenia. METHOD: This cross-sectional study investigated intelligence and educational performance in two outpatient samples [494 BD-I patients, 952 schizophrenia spectrum (SCZ) patients], 2231 relatives of BD-I and SCZ patients, 1104 healthy controls and 100 control siblings. Mixed-effects and regression models were used to compare groups on intelligence and educational performance. RESULTS: BD-I patients were more likely to have completed the highest level of education (odds ratio 1.88, 95% confidence interval 1.66-2.70) despite having a lower IQ compared to controls (ß = -9.09, S.E. = 1.27, p < 0.001). In contrast, SCZ patients showed both a lower IQ (ß = -15.31, S.E. = 0.86, p < 0.001) and lower educational levels compared to controls. Siblings of both patient groups had significantly lower IQ than control siblings, but did not differ on educational performance. IQ scores did not differ between BD-I parents and SCZ parents, but BD-I parents had completed higher educational levels. CONCLUSIONS: Although BD-I patients had a lower IQ than controls, they were more likely to have completed the highest level of education. This contrasts with SCZ patients, who showed both intellectual and educational deficits compared to healthy controls. Since relatives of BD-I patients did not demonstrate superior educational performance, our data suggest that high educational performance may be a distinctive feature of bipolar disorder patients.

Genome-wide association study of NMDA receptor coagonists in human cerebrospinal fluid and plasma.

The N-methyl-D-aspartate receptor (NMDAR) coagonists glycine, D-serine and L-proline play crucial roles in NMDAR-dependent neurotransmission and are associated with a range of neuropsychiatric disorders. We conducted the first genome-wide association study of concentrations of these coagonists and their enantiomers in plasma and cerebrospinal fluid (CSF) of human subjects from the general population (N=414). Genetic variants at chromosome 22q11.2, located in and near PRODH (proline dehydrogenase), were associated with L-proline in plasma (ß=0.29; P=6.38 × 10(-10)). The missense variant rs17279437 in the proline transporter SLC6A20 was associated with L-proline in CSF (ß=0.28; P=9.68 × 10(-9)). Suggestive evidence of association was found for the D-serine plasma-CSF ratio at the D-amino-acid oxidase (DAO) gene (ß=-0.28; P=9.08 × 10(-8)), whereas a variant in SRR (that encodes serine racemase and is associated with schizophrenia) constituted the most strongly associated locus for the L-serine to D-serine ratio in CSF. All these genes are highly expressed in rodent meninges and choroid plexus, anatomical regions relevant to CSF physiology. The enzymes and transporters they encode may be targeted to further construe the nature of NMDAR coagonist involvement in NMDAR gating. Furthermore, the highlighted genetic variants may be followed up in clinical populations, for example, schizophrenia and 22q11 deletion syndrome. Overall, this targeted metabolomics approach furthers the understanding of NMDAR coagonist concentration variability and sets the stage for non-targeted CSF metabolomics projects.

Antipsychotic use is associated with a blunted cortisol stress response: a study in euthymic bipolar disorder patients and their unaffected siblings.

There is ample evidence that the acute stress response is altered in schizophrenia and bipolar disorder. However, it is not clear whether such changes are related to the illness, a genetic vulnerability, or is the result of medication that is used in the majority of these patients. Therefore, we investigated determinants of the acute endocrine and autonomic stress response in healthy controls (n=48), euthymic BD1 patients (n=49) and unaffected siblings of BD1 patients (n=27). All participants completed a validated psychosocial stress task, the Trier Social Stress Test for Groups (TSST-G). Saliva levels of alpha-amylase and cortisol were measured before, during, and after exposure to stress. Compared to controls, we found a significantly blunted cortisol stress response in BD1 patients. Conversely, BD1 patients displayed exaggerated alpha-amylase levels in response to stress. Antipsychotic use was a significant contributing factor to the blunted cortisol stress response in BD1 patients. Unaffected BD1 siblings displayed similar stress-induced cortisol and alpha-amylase levels as controls, suggesting that familial risk for BD1 did not have a large effect on the functionality of the stress system. In conclusion, this study shows that euthymic BD1 patients have a substantially blunted endocrine stress response but an exaggerated autonomic stress response and that the endocrine stress response differences can be largely contributed to antipsychotic use rather than constitute a specific BD1 phenotype or vulnerability.

Change in cannabis use in the general population: a longitudinal study on the impact on psychotic experiences.

OBJECTIVE: To prospectively assess the relationship between cannabis use and psychotic experiences over time. METHOD: In a longitudinal design, young adults aged 18-27years (N=705) gave online information on cannabis use and completed the Community Assessment of Psychic Experiences (CAPE). These measures were repeated after an interval ranging from six months to five years. RESULTS: A decrease in cannabis use was associated with a decrease in total psychotic experiences (ß=-0.096, p=0.01) after adjustment for a range of potential confounders. An increase in cannabis use was associated with increased positive symptoms at follow-up (ß=0.07, p=0.02), but was not significantly associated with increases in Negative and Depression symptom scores, nor with the total number of psychotic experiences. CONCLUSION: In the first study to the association of change in cannabis use and psychotic experiences over time in the general population, we found an association between changes in cannabis use and changes in the frequency of psychotic experiences. While this does not prove a causal relationship between cannabis use and psychosis, our findings are consistent with studies suggesting that cessation of cannabis use may be beneficial in terms of reducing psychotic experiences.

Cannabis use is a better indicator of poor mental health in women than in men: a cross-sectional study in young adults from the general population.

Cannabis use is a known risk factor for a range of mental health problems, but less is known on the association with general mental health. We aim to explore the relationship between cannabis use and general mental health. We did a cross-sectional online survey of 1,929 young adults aged 18-30 years. Participants reported socio-demographic data, substance use and the Symptom Checklist-90 (SCL-90). Monthly cannabis use was associated with a higher total score on the SCL-90, both in a crude (OR 1.94, 95% CI 1.57-2.38) and fully adjusted model (OR 1.48, 95% CI 1.07-2.03). The association between cannabis and mental health was stronger in women and weekly users, and was independent of age at first use of cannabis. We conclude that moderate cannabis use is associated with general mental health problems in young adulthood. This relationship is independent of age at first use and of other risk factors, and is strongest in women.

Cannabidiol as a potential treatment for psychosis.

Although cannabis use is associated with an increased risk of developing psychosis, the cannabis constituent cannabidiol (CBD) may have antipsychotic properties. This review concisely describes the role of the endocannabinoid system in the development of psychosis and provides an overview of currently available animal, human experimental, imaging, epidemiological and clinical studies that investigated the antipsychotic properties of CBD. In this targeted literature review we performed a search for English articles using Medline and EMBASE. Studies were selected if they described experiments with psychosis models, psychotic symptoms or psychotic disorders as outcome measure and involved the use of CBD as intervention. Evidence from several research domains suggests that CBD shows potential for antipsychotic treatment.

Seasonal variation of serotonin turnover in human cerebrospinal fluid, depressive symptoms and the role of the 5-HTTLPR.

Studying monoaminergic seasonality is likely to improve our understanding of neurobiological mechanisms underlying season-associated physiological and pathophysiological behavior. Studies of monoaminergic seasonality and the influence of the serotonin-transporter-linked polymorphic region (5-HTTLPR) on serotonin seasonality have yielded conflicting results, possibly due to lack of power and absence of multi-year analyses. We aimed to assess the extent of seasonal monoamine turnover and examined the possible involvement of the 5-HTTLPR. To determine the influence of seasonality on monoamine turnover, 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) were measured in the cerebrospinal fluid of 479 human subjects collected during a 3-year period. Cosine and non-parametric seasonal modeling were applied to both metabolites. We computed serotonin (5-HT) seasonality values and performed an association analysis with the s/l alleles of the 5-HTTLPR. Depressive symptomatology was assessed using the Beck Depression Inventory-II. Circannual variation in 5-HIAA fitted a spring-peak cosine model that was significantly associated with sampling month (P=0.0074). Season of sampling explained 5.4% (P=1.57 × 10(-7)) of the variance in 5-HIAA concentrations. The 5-HTTLPR s-allele was associated with increased 5-HIAA seasonality (standardized regression coefficient=0.12, P=0.020, N=393). 5-HIAA seasonality correlated with depressive symptoms (Spearman's rho=0.13, P=0.018, N=345). In conclusion, we highlight a dose-dependent association of the 5-HTTLPR with 5-HIAA seasonality and a positive correlation between 5-HIAA seasonality and depressive symptomatology. The presented data set the stage for follow-up in clinical populations with a role for seasonality, such as affective disorders.

Interaction between the MTHFR C677T polymorphism and traumatic childhood events predicts depression.

Childhood trauma is associated with the onset and recurrence of major depressive disorder (MDD). The thermolabile T variant of the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism (rs1801133) is associated with a limited (oxidative) stress defense. Therefore, C677T MTHFR could be a potential predictor for depressive symptomatology and MDD recurrence in the context of traumatic stress during early life. We investigated the interaction between the C677T MTHFR variant and exposure to traumatic childhood events (TCEs) on MDD recurrence during a 5.5-year follow-up in a discovery sample of 124 patients with recurrent MDD and, in an independent replication sample, on depressive symptomatology in 665 healthy individuals from the general population. In the discovery sample, Cox regression analysis revealed a significant interaction between MTHFR genotype and TCEs on MDD recurrence (P=0.017). Over the 5.5-year follow-up period, median time to recurrence was 191 days for T-allele carrying patients who experienced TCEs (T+ and TCE+); 461 days for T- and TCE+ patients; 773 days for T+ and TCE- patients and 866 days for T- and TCE- patients. In the replication sample, a significant interaction was present between the MTHFR genotype and TCEs on depressive symptomatology (P=0.002). Our results show that the effects of TCEs on the prospectively assessed recurrence of MDD and self-reported depressive symptoms in the general population depend on the MTHFR genotype. In conclusion, T-allele carriers may be at an increased risk for depressive symptoms or MDD recurrence after exposure to childhood trauma.

Cigarette smoking and cannabis use are equally strongly associated with psychotic-like experiences: a cross-sectional study in 1929 young adults.

BACKGROUND: Cannabis use is associated with increased risk for psychotic-like experiences (PLEs) and psychotic disorders. It remains unclear whether this relationship is causal or due to confounding. METHOD: A total of 1929 young adults aged 18-30 years participated in a nationwide internet-based survey in The Netherlands and gave information on demographics, substance use and parental psychiatric illness and completed the Community Assessment of Psychic Experiences (CAPE). RESULTS: Cigarette smoking and cannabis use were equally strongly associated with the frequency of PLEs in a fully adjusted model (ß = 0.098 and 0.079 respectively, p < 0.05). Cannabis use was associated with distress from PLEs in a model adjusted for an elaborate set of confounders excluding smoking (ß = 0.082, p < 0.05). However, when cigarette smoking was included in the model, cannabis use was not a significant predictor of distress from PLEs. Cigarette smoking remained associated with distress from PLEs in a fully adjusted model (ß = 0.107, p < 0.001). CONCLUSIONS: Smoking is an equally strong independent predictor of frequency of PLEs as monthly cannabis use. Our results suggest that the association between moderate cannabis use and PLEs is confounded by cigarette smoking.

Cannabis use as an indicator of risk for mental health problems in adolescents: a population-based study at secondary schools.

BACKGROUND: Although the association between cannabis use and a wide range of psychiatric symptoms is fairly well established, it is not clear whether cannabis use is also a risk factor for general mental health problems at secondary school. Method A total of 10 324 secondary school children aged 11-16 years, participating in an ongoing Public Health Service School Survey, gave information on demographics, substance use, school factors and stressful life events and completed the Strengths and Difficulties Questionnaire (SDQ). RESULTS: Cannabis use in the past month was associated with a clinically relevant score on the SDQ [unadjusted odds ratio (OR) 4.46, 95% confidence interval (CI) 3.46-5.76]. Other risk factors associated with poor psychosocial functioning were: a low level of education, alcohol use, cigarette smoking, hard drug use, frequent truancy, an unfavourable school evaluation, feeling unsafe at school, being victimized, frequent absence due to illness, a mentally ill parent, molestation by a parent, financial problems and feeling distressed by an adverse event. In a full model adjusting for these risk factors, cannabis was not significantly associated with mental health problems, although an association at trend level was apparent. Of these risk factors, regular alcohol use, cigarette smoking, hard drug use, frequent truancy, an unfavourable school evaluation and frequent absence due to illness were also associated with cannabis use. CONCLUSIONS: The association between cannabis use and poor psychosocial functioning in adolescence is due, at least in part, to confounding by other risk factors. Thus, cannabis use can best be viewed as an indicator of risk for mental health problems in adolescence.

Region and state specific glutamate downregulation in major depressive disorder: a meta-analysis of (1)H-MRS findings.

For major depressive disorder (MDD), magnetic resonance spectroscopy ((1)H-MRS) studies of glutamate, glutamine and Glx (the composite measure of mainly glutamate and glutamine) have yielded inconclusive or seemingly inconsistent results. We therefore systematically reviewed whether in vivo concentrations of glutamate, glutamine and Glx measured with (1)H-MRS differ between MDD patients and controls. Meta-analysis including meta-regression, sensitivity, statistical heterogeneity, and publication bias analyses were conducted. Glutamate and Glx concentrations were found to be lower in the anterior cingulate cortex (ACC) in patients compared to controls (standardized mean difference (SMD) for glutamate with 95% CIs: -0.86, -1.55 to -0.17; and for Glx: -1.15, -1.86 to -0.44). In addition, Glx was decreased in all brain regions together in current episode patients (SMD: -0.62, -1.17 to -0.07). We conclude that in MDD, glutamate and possibly glutamine are downregulated primarily in the ACC and during depressive states. These results fit the central role of the ACC in depressive symptomatology and suggest that in MDD changes in glutamatergic neurotransmission are state-dependent.