Lower CSF HVA and 5-HIAA in bipolar disorder type 1 with a history of childhood ADHD

Clinical correlates of comorbid attention deficit hyperactivity disorder in adults suffering from bipolar disorder: A meta-analysis

OBJECTIVE

Attention deficit hyperactivity disorder is a frequent comorbid condition in adults with bipolar disorder. We performed a meta-analysis aimed at assessing sociodemographic and clinical correlates of attention deficit hyperactivity disorder in bipolar disorder.

METHOD

We searched main electronic databases up to June 2021. Random-effects meta-analyses, with relevant meta-regression and quality-based sensitivity analyses, were carried out to estimate the association between attention deficit hyperactivity disorder and putative correlates, grading the quality of evidence.

RESULTS

We included 43 studies, based on 38 independent samples. Attention deficit hyperactivity disorder participants were more likely to be males (odds ratio = 1.46; p < 0.001) and unemployed (odds ratio = 1.45; p = 0.045), and less likely to be married (odds ratio = 0.62; p = 0.014). They had an earlier onset of bipolar disorder (standardized mean difference = -0.36; p < 0.001); more mood episodes (standardized mean difference = 0.35; p = 0.007), particularly depressive (standardized mean difference = 0.30; p = 0.011) and mixed (standardized mean difference = 0.30; p = 0.031) ones; higher odds of using antidepressants (odds ratio = 1.80; p = 0.024) and attempted suicides (odds ratio = 1.83; p < 0.001) and lower odds of psychotic features (odds ratio = 0.63; p = 0.010). Moreover, they were more likely to have generalized anxiety disorder (odds ratio = 1.50; p = 0.019), panic disorder (odds ratio = 1.89; p < 0.001), social phobia (odds ratio = 1.61; p = 0.017), eating disorders (odds ratio = 1.91; p = 0.007), antisocial personality disorder (odds ratio = 3.59; p = 0.004) and substance (odds ratio = 2.29; p < 0.001) or alcohol (odds ratio = 2.28; p < 0.001) use disorders. Quality of the evidence was generally low or very low for the majority of correlates, except for bipolar disorder onset and alcohol/substance use disorders (high), and suicide attempts (moderate).

CONCLUSION

Comorbid bipolar disorder/attention deficit hyperactivity disorder may have some distinctive clinical features including an earlier onset of bipolar disorder and higher comorbid alcohol/substance use disorder rates. Further research is needed to identify additional clinical characteristics of this comorbidity.

Is ADHD severity in adults associated with the lifetime prevalence of comorbid depressive episodes and anxiety disorders?

Purpose:

The objective of the present study was to examine the association between ADHD severity and the lifetime prevalence of comorbid depressive episodes and anxiety disorders in adults with ADHD.

Subjects/materials and methods:

Analyses were based on data of the Conner's Adult ADHD Rating Scale (CAARS) and a parent study examining the epidemiology of adult ADHD in 17 GP practices in Budapest, Hungary. Subjects between 18 and 60 years were included in the screening phase (n = 3529). Out of 279 positively screened subjects 161 participated in a clinical interview and completed the CAARS to confirm the diagnosis. We applied four diagnostic criteria: “DSM-IV”; “No-onset” (DSM-IV criteria without the specific requirement for onset); “Symptoms-only” (DSM-IV symptom criterion only); and “Reduced symptoms-only” (DSM-IV symptom criterion with a reduced threshold for symptom count). The MINI PLUS 5.0 was used to assess psychiatric comorbidity.

Results:

ADHD severity, as measured by the CAARS ADHD Index, showed a significant positive association with the prevalence of comorbid depressive episodes in all but the “ADHD_No-onset” group (“DSM-IV”: F[1.23] = 8.39, P = 0.0081; “No-onset”: F(1.27) = 0.97, P = 0.3346; “Symptoms-only”: F[1.55] = 30.79, P < 0.0001; “Reduced symptoms-only”: F(1.62) = 26.69, P < 0.0001).

Discussion and conclusion:

Results indicate that ADHD symptom severity increases in association with lifetime comorbidity with depression.

ADHD with Comorbid Bipolar Disorders: A Systematic Review of Neurobiological, Clinical and Pharmacological Aspects Across the Lifespan

BACKGROUND

Attention deficit hyperactivity (ADHD) disorder is a neurodevelopmental disorder characterized by inattention, hyperactivity, disruptive behaviour, and impulsivity. Despite considered typical of children for a long time, the persistence of ADHD symptoms in adulthood gained increasing interest during the last decades. Indeed, its diagnosis, albeit controversial, is rarely carried out even because ADHD is often comorbid with several other psychiatric diosrders, in particular with bipolar disorders (BDs), a condition that complicates the clinical picture, assessment and treatment.

AIMS

The aim of this paper was to systematically review the scientific literature on the neurobiological, clinical features and current pharmacological management of ADHD comorbid with BDs across the entire lifespan, with a major focus on the adulthood.

DISCUSSION

The pharmacology of ADHD-BD in adults is still empirical and influenced by the individual experience of the clinicians. Stimulants are endowed of a prompt efficacy and safety, whilst non-stimulants are useful when a substance abuse history is detected, although they require some weeks in order to be fully effective. In any case, an in-depth diagnostic and clinical evaluation of the single individual is mandatory.

CONCLUSION

The comorbidity of ADHD with BD is still a controversial matter, as it is the notion of adult ADHD as a distinct nosological category. Indeed, some findings highlighted the presence of common neurobiological mechanisms and overlapping clinical features, although disagreement does exist. In any case, while expecting to disentangle this crucial question, a correct management of this comorbidity is essential, which requires the co-administration of mood stabilizers. Further controlled clinical studies in large samples of adult ADHD-BD patients appear extremely urgent in order to better define possible therapeutic guidelines, as well as alternative approaches for this potentially invalidating condition.

Executive functioning but not IQ or illness severity predicts occupational status in bipolar disorder

Background

Bipolar disorder is associated with significant functional deficits including occupational functioning. Despite the high rates of unemployment and sick leave in the patient population, only a limited number of studies have examined factors associated with occupational functioning in bipolar disorder. The aim of the study was to investigate the relative importance of demographic, clinical, and neuropsychological factors on occupational dysfunction in bipolar disorder.

Methods

A sample of 120 partially or fully remitted bipolar disorder I and II patients were included in the study. Patients were stratified into an active and an inactive group based on the number of hours per week working or studying. Active (n = 86) and inactive (n = 34) patients were compared with respect to demographic factors, clinical characteristics, medication, measures of psychosocial functioning, and cognitive functioning (i.e., IQ and executive functions). No other cognitive domains were examined.

Results

Univariate analyses revealed better overall cognitive function in active patients in terms of IQ and executive functioning. However, only executive functioning accounted for a significant amount of the variance in occupational status when other significant predictors were taken into account.

Conclusions

Executive functioning was a more powerful predictor of occupational status in bipolar disorder patients than IQ and other clinical factors, including illness severity.

Genome-wide study of immune biomarkers in cerebrospinal fluid and serum from patients with bipolar disorder and controls

Bipolar disorder is a common, chronic psychiatric disorder. Despite high heritability, there is a paucity of identified genetic risk factors. Immune biomarkers are under more direct genetic influence than bipolar disorder. To explore the genetic associations with immune biomarker levels in cerebrospinal fluid (CSF) and blood serum which previously showed differences in bipolar disorder, we performed a study involving 291 individuals (184 bipolar disorder patients and 107 controls). The biomarkers assayed in both CSF and serum were: chitinase-3-like protein-1 (YKL-40), monocyte chemoattractant protein-1 (MCP-1), soluble cluster of differentiation (sCD14), tissue inhibitor of metalloproteinases-1 and 2 (TIMP-1 and TIMP-2). C-reactive protein (CRP) was only quantified in serum, and interleukin 8 (IL-8) measures were only available in CSF. Genome-wide association studies were conducted using PLINK for each of three genotyping waves and incorporated covariates for population substructure, age, sex, and body mass index (BMI). Results were combined by meta-analysis. Genome-wide significant associations were detected for all biomarkers except TIMP-1 and TIMP-2 in CSF. The strongest association in CSF was found for markers within the CNTNAP5 gene with YKL-40 (rs150248456, P = 2.84 × 10^-10). The strongest association in serum was also for YKL-40 but localized to the FANCI gene (rs188263039, P = 5.80 × 10^-26). This study revealed numerous biologically plausible genetic associations with immune biomarkers in CSF and blood serum. Importantly, the genetic variants regulating immune biomarker levels in CSF and blood serum differ. These results extend our knowledge of how biomarkers showing alterations in bipolar disorder are genetically regulated.

Associations of serotonin transporter gene promoter polymorphisms and monoamine oxidase A gene polymorphisms with oppositional defiant disorder in a Chinese Han population

BACKGROUND

Oppositional defiant disorder (ODD) is a behavioral disorder that mainly refers to a recurrent pattern of disobedient, defiant, negativistic and hostile behaviors toward authority figures. Previous studies have showed associations of serotonin transporter (5-HTT) and monoamine oxidase A (MAOA) with behavioral and psychiatric disorders. The purposes of this study were to investigate the potential association of 5-HTT gene promoter polymorphism (5-HTTLPR) and MAOA gene polymorphism with susceptibility to ODD in a Han Chinese school population.

METHODS

The 5-HTTLPR gene polymorphism and the MAOA gene polymorphism were genotyped in a case-control study of 257 Han Chinese children (123 ODD and 134 healthy controls).

RESULTS

There was significant difference in the allele distribution of 5-HTTLPR (χ² = 7.849, P = 0.005) between the ODD and control groups. Further, there were significant differences in genotype (χ² = 5.168, P = 0.023) and allele distributions (χ² = 10.336, P = 0.001) of the MAOA gene polymorphism that is variable-number tandem repeat (MAOA-uVNTR) between two groups. Moreover, there were significant differences in genotype (χ² = 4.624, P = 0.032) and allele distributions (χ² = 9.248, P = 0.002) of MAOA-uVNTR only in the male ODD and healthy groups.

CONCLUSIONS

Our results suggest that 5-HTTLPR and MAOA-uVNTR gene variants may contribute to susceptibility to ODD. Further, MAOA-uVNTR gene polymorphism may play a role in susceptibility to ODD only in male children.

Cerebrospinal fluid monoamine metabolite profiles in bipolar disorder, ADHD, and controls

Alterations in monoaminergic signaling are suggested as key aspects of the pathophysiology in bipolar disorder and ADHD, but it is not known if the monoamine metabolic profile differs between these disorders. One method to study monoaminergic systems in humans is to measure monoamine end-point metabolite concentrations in cerebrospinal fluid (CSF). Here, we analyzed CSF monoamine metabolite concentrations in 103 adults with bipolar disorder, 72 adults with ADHD, and 113 controls. Individuals with bipolar disorder had significantly higher homovanillic acid (HVA, 264 ± 112 nmol/L, p < 0.001) and 5-hydroxyindoleacetic acid (5-HIAA, 116 ± 42 nmol/L, p = 0.001) concentration, but lower 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG, 38 ± 8 nmol/L, p < 0.001) concentrations than controls (HVA, 206 ± 70 nmol/L; 5-HIAA, 98 ± 31 nmol/L; and MHPG, 42 ± 7 nmol/L). Higher HVA concentrations were associated with a history of psychosis in the bipolar disorder sample. Subjects with ADHD had higher HVA (240 ± 94 nmol/L, p < 0.001) concentrations compared with controls. In addition, SSRI treatment was associated with lower 5-HIAA concentrations in both patient groups. A power analysis indicated that for within-group comparisons, only large effects would be reliably detectable. Thus, there may be moderate-to-small effects caused by medication that were not detected due to the limited size of the sub-groups in these analyses. In conclusion, the present study suggests disorder-specific alterations of CSF monoamine metabolite concentrations in patients with bipolar disorder and ADHD compared with controls; these differences were independent of acute symptoms and medication effects.

The Risk of Treatment-Emergent Mania With Methylphenidate in Bipolar Disorder

OBJECTIVE

The authors sought to determine the risk of treatment-emergent mania associated with methylphenidate, used in monotherapy or with a concomitant mood-stabilizing medication, in patients with bipolar disorder.

METHOD

Using linked Swedish national registries, the authors identified 2,307 adults with bipolar disorder who initiated therapy with methylphenidate between 2006 and 2014. The cohort was divided into two groups: those with and those without concomitant mood-stabilizing treatment. To adjust for individual-specific confounders, including disorder severity, genetic makeup, and early environmental factors, Cox regression analyses were used, conditioning on individual to compare the rate of mania (defined as hospitalization for mania or a new dispensation of stabilizing medication) 0-3 months and 3-6 months after medication start following nontreated periods.

RESULTS

Patients on methylphenidate monotherapy displayed an increased rate of manic episodes within 3 months of medication initiation (hazard ratio=6.7, 95% CI=2.0-22.4), with similar results for the subsequent 3 months. By contrast, for patients taking mood stabilizers, the risk of mania was lower after starting methylphenidate (hazard ratio=0.6, 95% CI=0.4-0.9). Comparable results were observed when only hospitalizations for mania were counted.

CONCLUSIONS

No evidence was found for a positive association between methylphenidate and treatment-emergent mania among patients with bipolar disorder who were concomitantly receiving a mood-stabilizing medication. This is clinically important given that up to 20% of people with bipolar disorder suffer from comorbid ADHD. Given the markedly increased hazard ratio of mania following methylphenidate initiation in bipolar patients not taking mood stabilizers, careful assessment to rule out bipolar disorder is indicated before initiating monotherapy with psychostimulants.

Peripheral blood gene expression profiles linked to monoamine metabolite levels in cerebrospinal fluid

The blood-brain barrier separates circulating blood from the central nervous system (CNS). The scope of this barrier is not fully understood which limits our ability to relate biological measurements from peripheral to central phenotypes. For example, it is unknown to what extent gene expression levels in peripheral blood are reflective of CNS metabolism. In this study, we examine links between central monoamine metabolite levels and whole-blood gene expression to better understand the connection between peripheral systems and the CNS. To that end, we correlated the prime monoamine metabolites in cerebrospinal fluid (CSF) with whole-genome gene expression microarray data from blood (N=240 human subjects). We additionally applied gene-enrichment analysis and weighted gene co-expression network analyses (WGCNA) to identify modules of co-expressed genes in blood that may be involved with monoamine metabolite levels in CSF. Transcript levels of two genes were significantly associated with CSF serotonin metabolite levels after Bonferroni correction for multiple testing: THAP7 (P=2.8 × 10^-8, β=0.08) and DDX6 (P=2.9 × 10^-7, β=0.07). Differentially expressed genes were significantly enriched for genes expressed in the brain tissue (P=6.0 × 10^-52). WGCNA revealed significant correlations between serotonin metabolism and hub genes with known functions in serotonin metabolism, for example, HTR2A and COMT. We conclude that gene expression levels in whole blood are associated with monoamine metabolite levels in the human CSF. Our results, including the strong enrichment of brain-expressed genes, illustrate that gene expression profiles in peripheral blood can be relevant for quantitative metabolic phenotypes in the CNS.

Cerebrospinal fluid metabolomics identifies a key role of isocitrate dehydrogenase in bipolar disorder: evidence in support of mitochondrial dysfunction hypothesis

Although evidence for mitochondrial dysfunction in the pathogenesis of bipolar disorder (BD) has been reported, the precise biological basis remains unknown, hampering the search for novel biomarkers. In this study, we performed metabolomics of cerebrospinal fluid (CSF) from male BD patients (n=54) and age-matched male healthy controls (n=40). Subsequently, post-mortem brain analyses, genetic analyses, metabolomics of CSF samples from rats treated with lithium or valproic acid were also performed. After multivariate logistic regression, isocitric acid (isocitrate) levels were significantly higher in the CSF from BD patients than healthy controls. Furthermore, gene expression of two subtypes (IDH3A and IDH3B) of isocitrate dehydrogenase (IDH) in the dorsolateral prefrontal cortex from BD patients was significantly lower than that of controls, although the expression of other genes including, aconitase (ACO1, ACO2), IDH1, IDH2 and IDH3G, were not altered. Moreover, protein expression of IDH3A in the cerebellum from BD patients was higher than that of controls. Genetic analyses showed that IDH genes (IDH1, IDH2, IDH3A, IDH3B) and ACO genes (ACO1, ACO2) were not associated with BD. Chronic (4 weeks) treatment with lithium or valproic acid in rats did not alter CSF levels of isocitrate, and mRNA levels of Idh3a, Idh3b, Aco1 and Aco2 genes in the rat brain. These findings suggest that abnormality in the metabolism of isocitrate by IDH3A in the mitochondria plays a key role in the pathogenesis of BD, supporting the mitochondrial dysfunction hypothesis of BD. Therefore, IDH3 in the citric acid cycle could potentially be a novel therapeutic target for BD.

Blood metabolomics analysis identifies abnormalities in the citric acid cycle, urea cycle, and amino acid metabolism in bipolar disorder

Background

Bipolar disorder (BD) is a severe and debilitating psychiatric disorder. However, the precise biological basis remains unknown, hampering the search for novel biomarkers. We performed a metabolomics analysis to discover novel peripheral biomarkers for BD.

Methods

We quantified serum levels of 116 metabolites in mood-stabilized male BD patients (n = 54) and age-matched male healthy controls (n = 39).

Results

After multivariate logistic regression, serum levels of pyruvate, N-acetylglutamic acid, α-ketoglutarate, and arginine were significantly higher in BD patients than in healthy controls. Conversely, serum levels of β-alanine, and serine were significantly lower in BD patients than in healthy controls. Chronic (4-weeks) administration of lithium or valproic acid to adult male rats did not alter serum levels of pyruvate, N-acetylglutamic acid, β-alanine, serine, or arginine, but lithium administration significantly increased serum levels of α-ketoglutarate.

Conclusions

The metabolomics analysis demonstrated altered serum levels of pyruvate, N-acetylglutamic acid, β-alanine, serine, and arginine in BD patients.

General significance

The present findings suggest that abnormalities in the citric acid cycle, urea cycle, and amino acid metabolism play a role in the pathogenesis of BD.

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Metabolomics analysis of serum sample from bipolar disorder (BD) was performed.

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Pyruvate, N-acetylglutamic acid, α-ketoglutarate, and arginine were higher in BD.

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β-alanine, and serine were lower in BD patients.

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Abnormalities in citric acid cycle, urea cycle, and amino acid metabolism in BD.

Subcortical morphometry and psychomotor function in euthymic bipolar disorder with a history of psychosis

Psychomotor disturbances are prominent in bipolar disorder patients with a history of psychosis, but their neural correlates remain largely unexplored. We hypothesized that these psychomotor disturbances are associated with morphometric changes in functionally specific regions of the basal ganglia and thalamus. To test if psychomotor performance is associated with changes in volume and shape in these brain regions, we investigated 20 euthymic bipolar disorder patients with a history of psychosis and 20 healthy controls with structural magnetic resonance imaging and vertex-based morphometry. Within the patient group, the local shape of the basal ganglia was significantly associated with longer duration of illness, increased number of manic episodes, and treatment with antipsychotics. There were neither any statistically significant associations between psychomotor performance and morphometric measures in the patient group, nor any significant morphometric differences between patients and controls. We conclude that euthymic subjects with bipolar disorder and a previous history of psychosis show shape changes in regions of the basal ganglia associated to clinical variables that may predict psychomotor disturbances in bipolar disorder.

Monocyte and microglial activation in patients with mood-stabilized bipolar disorder

BACKGROUND

Bipolar disorder is associated with medical comorbidities that have been linked to systemic inflammatory mechanisms. There is, however, limited evidence supporting a role of neuroinflammation in bipolar disorder. Here we tested whether microglial activation and associated tissue remodelling processes are related to bipolar disorder by analyzing markers in cerebrospinal fluid (CSF) and serum from patients and healthy controls.

METHODS

Serum was sampled from euthymic patients with bipolar disorder and healthy controls, and CSF was sampled from a large subset of these individuals. The levels of monocyte chemoattractant protein-1 (MCP-1), YKL-40, soluble cluster of differentiation 14 (sCD14), tissue inhibitor of metalloproteinases-1 (TIMP-1) and tissue inhibitor of metalloproteinases-2 (TIMP-2), were measured, and we adjusted comparisons between patients and controls for confounding factors.

RESULTS

We obtained serum samples from 221 patients and 112 controls and CSF samples from 125 patients and 87 controls. We found increased CSF levels of MCP-1 and YKL-40 and increased serum levels of sCD14 and YKL-40 in patients compared with controls; these differences remained after controlling for confounding factors, such as age, sex, smoking, blood-CSF barrier function, acute-phase proteins and body mass index. The CSF levels of MCP-1 and YKL-40 correlated with the serum levels, whereas the differences between patients and controls in CSF levels of MCP-1 and YKL-40 were independent of serum levels.

LIMITATIONS

The cross-sectional study design precludes conclusions about causality.

CONCLUSION

Our results suggest that both neuroinflammatory and systemic inflammatory processes are involved in the pathophysiology of bipolar disorder. Importantly, markers of immunological processes in the brain were independent of peripheral immunological activity.

Cognitive functioning in clinically stable patients with bipolar disorder I and II

OBJECTIVES

Bipolar disorder is accompanied by cognitive impairments, which persists during euthymic phases. The purpose of the present study was to identify those neuropsychological tests that most reliably tell euthymic bipolar patients and controls apart, and to clarify the extent to which these cognitive impairments are clinically significant as judged from neuropsychological norms.

METHODS

Patients with bipolar disorder (type I: n = 64; type II: n = 44) and controls (n = 86) were examined with a comprehensive neuropsychological test battery yielding 47 measures of executive functioning, speed, memory, and verbal skills. Multivariate analysis was used to build a model of cognitive performance with the ability to expose underlying trends in data and to reveal cognitive differences between patients and controls.

RESULTS

Patients with bipolar disorder and controls were partially separated by one predictive component of cognitive performance. Additionally, the relative relevance of each cognitive measure for such separation was decided. Cognitive tests measuring set shifting, inhibition, fluency, and searching (e.g., Trail Making Test, Color-Word) had strongest discriminating ability and most reliably detected cognitive impairments in the patient group.

CONCLUSIONS

Both bipolar disorder type I and type II were associated with cognitive impairment that for a sizeable minority is significant in a clinical neuropsychological sense. We demonstrate a combination of neuropsychological tests that reliably detect cognitive impairment in bipolar disorder.

Markers of glutamate signaling in cerebrospinal fluid and serum from patients with bipolar disorder and healthy controls

Glutamate is the major excitatory neurotransmitter in the brain. Aberrations in glutamate signaling have been linked to the pathophysiology of mood disorders. Increased plasma levels of glutamate as well as higher glutamine+glutamate levels in the brain have been demonstrated in patients with bipolar disorder as compared to healthy controls. In this study, we explored the glutamate hypothesis of bipolar disorder by examining peripheral and central levels of amino acids related to glutamate signaling. A total of 215 patients with bipolar disorder and 112 healthy controls from the Swedish St. Göran bipolar project were included in this study. Glutamate, glutamine, glycine, L-serine and D-serine levels were determined in serum and in cerebrospinal fluid using high performance liquid chromatography with fluorescence detection. Serum levels of glutamine, glycine and D-serine were significantly higher whereas L-serine levels were lower in patients with bipolar disorder as compared to controls. No differences between the patient and control group in amino acid levels were observed in cerebrospinal fluid. The observed differences in serum amino acid levels may be interpreted as a systemic aberration in amino acid metabolism that affects several amino acids related to glutamate signaling.

Adult ADHD and suicide

While suicidal behaviour has been implicated in a plethora of psychiatric disorders including depression, psychoses and substance abuse, its association with adult ADHD is largely under-researched. Given that emotional instability and the high prevalence of comorbid conditions such as mood disorders and alcohol/drug dependence are typical for ADHD, the question of suicide risk must not be neglected in this patient group. A review of the current literature focusing on this issue provides strong evidence that ADHD patients are at a significant risk for experiencing suicidal ideations and committing suicide. For daily clinical practice, it is therefore essential to incorporate this aspect into the diagnostic and therapeutic process and to take preventive measures.

Abnormality in serum levels of mature brain-derived neurotrophic factor (BDNF) and its precursor proBDNF in mood-stabilized patients with bipolar disorder: a study of two independent cohorts

BACKGROUND

Early detection and diagnosis of bipolar disorder can be difficult. Tools are needed to help clinicians detect bipolar disorder earlier, which would ameliorate the prognosis.

METHODS

ELISA kits that distinguish between mature brain derived neurotrophic factor (BDNF) and proBDNF, we compared serum levels of mature BDNF, proBDNF, and matrix metalloproteinase-9 (MMP-9) in two independent cohorts (Sahlgrenska cohort and Karolinska cohort) of mood-stabilized bipolar patients and healthy controls. The total sample size in both cohorts consisted of 263 (48+215) bipolar patients and 155 (43+112) healthy controls.

RESULTS

Levels of mature BDNF and the ratio mature BDNF/proBDNF were significantly higher in patients than in controls. Serum levels of proBDNF were significantly lower in patients compared to controls. Serum levels of MMP-9 did not differ between the groups but MMP-9 correlated positively and significantly with mature BDNF. Mature BDNF, proBDNF, the ratio of mature BDNF/proBDNF and interactions with MMP-9 explained the diagnostic dichotomy in both cohorts with high significance, using multivariate logistic ANCOVA (gender, age, and BMI were covaried out). The model explained 41% of the diagnostic variance in the Sahlgrenska cohort (p<0.0001) and 15% in the Karolinska cohort (p<0.0001). In both cohorts, the equations provided good power for diagnostic classification. The diagnostic sensitivity was 89% in the Sahlgrenska and 74% in the Karolinska cohort, and specificity 77% and 64%, respectively.

LIMITATION

The study is cross-sectional with no longitudinal follow up. The cohorts are relatively small with no medication-free patients. There are no "ill patient controls".

CONCLUSION

Abnormalities in the conversion of proBDNF to mature BDNF may be associated with pathogenesis of bipolar disorder. Clinical use of these biomarkers may provide opportunities for earlier detection and correct treatment.

The KMO allele encoding Arg452 is associated with psychotic features in bipolar disorder type 1, and with increased CSF KYNA level and reduced KMO expression

The kynurenine pathway metabolite kynurenic acid (KYNA), modulating glutamatergic and cholinergic neurotransmission, is increased in cerebrospinal fluid (CSF) of patients with schizophrenia or bipolar disorder type 1 with psychotic features. KYNA production is critically dependent on kynurenine 3-monooxygenase (KMO). KMO mRNA levels and activity in prefrontal cortex (PFC) are reduced in schizophrenia. We hypothesized that KMO expression in PFC would be reduced in bipolar disorder with psychotic features and that a functional genetic variant of KMO would associate with this disease, CSF KYNA level and KMO expression. KMO mRNA levels were reduced in PFC of bipolar disorder patients with lifetime psychotic features (P=0.005, n=19) or schizophrenia (P=0.02, n=36) compared with nonpsychotic patients and controls. KMO genetic association to psychotic features in bipolar disorder type 1 was studied in 493 patients and 1044 controls from Sweden. The KMO Arg(452) allele was associated with psychotic features during manic episodes (P=0.003). KMO Arg(452) was studied for association to CSF KYNA levels in an independent sample of 55 Swedish patients, and to KMO expression in 717 lymphoblastoid cell lines and 138 hippocampal biopsies. KMO Arg(452) associated with increased levels of CSF KYNA (P=0.03) and reduced lymphoblastoid and hippocampal KMO expression (P≤0.05). Thus, findings from five independent cohorts suggest that genetic variation in KMO influences the risk for psychotic features in mania of bipolar disorder patients. This provides a possible mechanism for the previous findings of elevated CSF KYNA levels in those bipolar patients with lifetime psychotic features and positive association between KYNA levels and number of manic episodes.

Revisiting the serotonin-aggression relation in humans: a meta-analysis

The inverse relation between serotonin and human aggression is often portrayed as "reliable," "strong," and "well established" despite decades of conflicting reports and widely recognized methodological limitations. In this systematic review and meta-analysis, we evaluate the evidence for and against the serotonin deficiency hypothesis of human aggression across 4 methods of assessing serotonin: (a) cerebrospinal fluid levels of 5-hydroxyindoleacetic acid (CSF 5-HIAA), (b) acute tryptophan depletion, (c) pharmacological challenge, and (d) endocrine challenge. Results across 175 independent samples and over 6,500 total participants were heterogeneous, but, in aggregate, revealed a small, inverse correlation between serotonin functioning and aggression, anger, and hostility (r = -.12). Pharmacological challenge studies had the largest mean weighted effect size (r = -.21), and CSF 5-HIAA studies had the smallest (r = -.06). Potential methodological and demographic moderators largely failed to account for variability in study outcomes. Notable exceptions included year of publication (effect sizes tended to diminish with time) and self- versus other-reported aggression (other-reported aggression was positively correlated to serotonin functioning). We discuss 4 possible explanations for the pattern of findings: unreliable measures, ambient correlational noise, an unidentified higher order interaction, and a selective serotonergic effect. Finally, we provide 4 recommendations for bringing much needed clarity to this important area of research: acknowledge contradictory findings and avoid selective reporting practices; focus on improving the reliability and validity of serotonin and aggression measures; test for interactions involving personality and/or environmental moderators; and revise the serotonin deficiency hypothesis to account for serotonin's functional complexity.

Risk of bipolar disorder and schizophrenia in relatives of people with attention-deficit hyperactivity disorder

BACKGROUND

Attention-deficit hyperactivity disorder (ADHD) is associated with bipolar disorder and schizophrenia, and it has been suggested that combined bipolar disorder and ADHD is aetiologically distinct from the pure disorders.

AIMS

To clarify whether ADHD shares genetic and environmental factors with bipolar disorder and schizophrenia.

METHOD

By linking longitudinal Swedish national registers, we identified 61 187 persons with ADHD (the proband group) and their first- and second-degree relatives, and matched them with a control group of people without ADHD and their corresponding relatives. Conditional logistic regression was used to determine the risks of bipolar disorder and schizophrenia in the relatives of the two groups.

RESULTS

First-degree relatives of the ADHD proband group were at increased risk of both bipolar disorder (odds ratio (OR) = 1.84-2.54 for parents, offspring and full siblings) and schizophrenia (OR = 1.71-2.22 for parents, offspring and full siblings). The risks of bipolar disorder and schizophrenia among second-degree relatives were substantially lower than among full siblings.

CONCLUSIONS

These findings suggest that the co-occurrence of ADHD and bipolar disorder as well as ADHD and schizophrenia is due to shared genetic factors, rather than representing completely aetiologically distinct subsyndromes.

Neurocognitive function in bipolar disorder: a comparison between bipolar I and II disorder and matched controls

BACKGROUND

Cognitive deficits have been documented in patients with bipolar disorder. Further, it has been suggested that the degree and type of cognitive impairment differ between bipolar I and bipolar II disorder, but data is conflicting and remains inconclusive. This study aimed to clarify the suggested differences in cognitive impairment between patients with bipolar I and II disorder in a relatively large, clinically stable sample while controlling for potential confounders.

METHODS

67 patients with bipolar I disorder, 43 with bipolar II disorder, and 86 randomly selected population-based healthy controls were compared. A number of neuropsychological tests were administered, assessing verbal and visual memory and executive functions. Patients were in a stable phase during testing.

RESULTS

Patients with bipolar type I and type II were cognitively impaired compared to healthy controls, but there were no statistically significant differences between the two subtypes. The strongest predictor of cognitive impairment within the patient group was current antipsychotic treatment.

CONCLUSIONS

The present study suggests that the type and degree of cognitive dysfunction is similar in bipolar I and II patients. Notably, treatment with antipsychotics - but not a history of psychosis - was associated with more severe cognitive impairment. Given that patients with bipolar I disorder are more likely to be on antipsychotic drugs, this might explain why some previous studies have found that patients with type I bipolar disorder are more cognitively impaired than those with type II.

Altered concentrations of amyloid precursor protein metabolites in the cerebrospinal fluid of patients with bipolar disorder

Bipolar disorder is a psychiatric disorder characterized by recurrent episodes of mania/hypomania and depression. Progressive cognitive dysfunction such as impairments in executive function and verbal memory is common in euthymic bipolar patients. The cerebrospinal fluid has previously been used to study neurodegenerative processes in Alzheimer's disease, from which changes in three core biomarkers have emerged as indicative of degeneration: amyloid β, total tau, and hyperphosphorylated tau. Here, neurodegeneration in bipolar disorder was investigated by assessing the association between bipolar disorder and cerebrospinal fluid biomarkers for neurodegenerative processes. Cerebrospinal fluid was obtained from 139 bipolar disorder patients and 71 healthy controls. Concentrations of total and phosphorylated tau, amyloid β1-42, amyloid β38/β40/β42, and the soluble forms of amyloid precursor protein were measured in patients vs controls. The concentrations of the soluble forms of amyloid precursor protein were significantly lower in bipolar patients compared with controls. The amyloid β42/amyloid β38 and the amyloid β42/amyloid β40 ratios were higher in bipolar patients than controls. There were no discernible differences in the concentrations of total/phosphorylated tau, amyloid β1-42, or amyloid β38/β40/β42. The concentrations of the biomarkers within the bipolar patient group were further associated with different ongoing medical treatments and diagnostic subgroups. The findings suggest that the amyloid precursor protein metabolism is altered in bipolar disorder. The results may have implications for the understanding of the pathophysiology of bipolar disorder and for the development of treatment strategies. Importantly, there were no signs of an Alzheimer-like neurodegenerative process among bipolar patients.

AKR1C4 gene variant associated with low euthymic serum progesterone and a history of mood irritability in males with bipolar disorder

BACKGROUND

Irritable mood during mood elevation is common in bipolar disorder. The progesterone metabolite allopregnanolone (ALLO) has been implicated in other disorders presenting with irritability. This study aimed to test whether a history of manic/hypomanic irritability is associated with low serum progesterone levels; and whether single nucleotide polymorphisms (SNPs) in gene coding for steroidogenetic enzymes (HSD3B2, SRD5A1 and AKR1C4 were coupled to previous manic irritability and/or with serum progesterone concentrations.

METHODS

Morning serum progesterone concentrations during euthymic phase of bipolar illness types 1 and 2 were assessed in 71 males and 107 females. Previous manic/hypomanic irritability was assessed using the Affective Disorders Evaluation. Selected SNPs were analyzed: i) aldoketoreductase-type-4 (AKR1C4 - rs17306779, rs3829125, rs10904440, rs12762017, and rs11253048), ii) 3-β-hydroxysteroid-dehydrogenase (HSD3B2 - rs4659174, rs2854964, and rs3765948), iii) steroid-5-α-reductase (SRD5A1 - rs8192139, rs181807, rs3822430, and rs3736316).

RESULTS

In males, progesterone concentrations were lower in those who had shown manic/hypomanic irritability compared with nonirritable (F=7.05, p=0.0099). SNPs rs17306779, rs3829125, and rs10904440 were associated with manic/hypomanic irritability. A cystine to serine change at position 145 in AKR1C4 (rs3829125) was associated with lower serum progesterone (F=6.34, p=0.014). There were no associations in females.

LIMITATIONS

Relatively small sample sizes.

CONCLUSION

Low progesterone levels and a cystine to serine change at position 145 in AKR1C4 gene are associated with manic/hypomanic irritability in males. Given that the enzyme AKR1C4 has both dehydrogenating and reductive activities in the steroidogenetic pathway, a missense variation in the gene may predispose to manic/hypomanic irritability by altering the relationship between progesterone and ALLO concentrations in the brain.

Ningdong granule: a complementary and alternative therapy in the treatment of attention deficit/hyperactivity disorder

BACKGROUND

Attention deficit/hyperactivity disorder (ADHD) is a common neurobehavioral and neuropsychiatric disorder in school-age children, and recent studies provide evidence implicating the metabolic abnormalities of dopamine (DA) for its pathophysiology. Methylphenidate, a kind of psychostimulant, is widely used in the treatment of ADHD, but some patients do not respond to it or cannot bear its side effects. As a traditional Chinese medicine preparation, Ningdong granule (NDG) has been used in the treatment of ADHD for several years in China. However, a systematical pharmacological study on its safety and mechanism still remains obscure.

OBJECTIVE

This paper aims to evaluate the efficiency, safety, and possible mechanism of NDG on ADHD children compared to methylphenidate.

METHODS

Seventy-two ADHD children were recruited to perform an 8-week, randomized, methylphenidate-controlled, doubled-blinded trial. The subjects were equally assigned to two groups receiving either NDG 5 mg/kg/day or methylphenidate 1 mg/kg/day for 8 weeks. The efficiency was assessed by the Teacher and Parent ADHD Rating Scales every 2 weeks for a total of 8 weeks. The side effects were recorded during the study. Blood, urine, and stool routine samples, liver and renal function test, and DA and homovanillic acid (HVA) concentration in sera were tested at the beginning and end of the trial.

RESULTS

NDG ameliorated ADHD symptoms after an 8-week medication with fewer side effects compared to methylphenidate (P < 0.05). The result also showed NDG to be safe and tolerable for ADHD children as monitored by the blood, urine, and stool analysis and liver and renal function for 8 weeks (P < 0.05). Moreover, the level of HVA in sera increased in NDG-treated group (P < 0.05), while the content of DA had no significant change during the study. An analysis of Pearson correlation coefficients also showed that the increased content of HVA in sera was associated with the improved scores of Teacher and Parent ADHD Rating Scales.

CONCLUSIONS

Compared to methylphenidate, NDG is effective and safe for ADHD children in the short term, increases the HVA concentration in sera to regulate DA metabolism, and promises to be an alternative medication, safely and effectively.

Manic episodes are associated with grey matter volume reduction - a voxel-based morphometry brain analysis

OBJECTIVE

To investigate whether the lifetime number of affective episodes or illness duration is associated with changes in local grey matter volume, in patients with bipolar I disorder without comorbid conditions.

METHOD

Magnetic resonance imaging scans of 55 patients with bipolar I disorder were analysed using VBM.

RESULTS

Smaller grey matter volume in the inferior frontal gyri of the dorsolateral prefrontal cortices (DLPFC) correlated significantly to the lifetime number of manic episodes. No association between local grey matter volume and the lifetime number of depression episodes or illness duration was found.

CONCLUSION

We found strong evidence for a linear correlation between a decrease in DLPFC volume and the lifetime number of manic episodes in patients with bipolar I disorder. Interestingly, DLPFC is known to be important for executive functions and the findings in this study might hence be linked to the executive cognitive deficits associated with bipolar disorder.