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A subgroup of individuals with mood and psychotic disorders shows evidence of inflammation that leads to activation of the kynurenine pathway and the increased production of neuroactive kynurenine metabolites. Depression is hypothesized to be causally associated with an imbalance in the kynurenine pathway, with an increased metabolism down the 3-hydroxykynurenine (3HK) branch of the pathway leading to increased levels of the neurotoxic metabolite, quinolinic acid (QA), which is a putative N -methyl- d -aspartate (NMDA) receptor agonist. In contrast, schizophrenia and psychosis are hypothesized to arise from increased metabolism of the NMDA receptor antagonist, kynurenic acid (KynA), leading to hypofunction of GABAergic interneurons, the disinhibition of pyramidal neurons and striatal hyperdopaminergia. Here we present results that challenge the model of excess KynA production in affective psychosis. After rigorous control of potential confounders and multiple testing we find significant reductions in serum KynA and/or KynA/QA in acutely ill inpatients with major depressive disorder ( N =35), bipolar disorder ( N =53) and schizoaffective disorder ( N =40) versus healthy controls ( N =92). No significant difference was found between acutely ill inpatients with schizophrenia ( n =21) and healthy controls. Further, a post hoc comparison of patients divided into the categories of non-psychotic affective disorder, affective psychosis and psychotic disorder (non-affective) showed that the greatest decrease in KynA was in the affective psychosis group relative to the other diagnostic groups. Our results are consistent with reports of elevations in proinflammatory cytokines in psychosis, and preclinical work showing that inflammation upregulates the enzyme, kynurenine mono-oxygenase ( KMO ), which converts kynurenine into 3-hydroxykynurenine and quinolinic acid.

Environmental stressors during childhood and adolescence influence postnatal brain maturation and human behavioral patterns in adulthood. Accordingly, excess stressors result in adult-onset neuropsychiatric disorders. We describe an underlying mechanism in which glucocorticoids link adolescent stressors to epigenetic controls in neurons. In a mouse model of this phenomenon, a mild isolation stress affects the mesocortical projection of dopaminergic neurons in which DNA hypermethylation of the tyrosine hydroxylase gene is elicited, but only when combined with a relevant genetic risk for neuropsychiatric disorders. These molecular changes are associated with several neurochemical and behavioral deficits that occur in this mouse model, all of which are blocked by a glucocorticoid receptor antagonist. The biology and phenotypes of the mouse models resemble those of psychotic depression, a common and debilitating psychiatric disease.

The disrupted in schizophrenia 1 (DISC1) gene is a candidate susceptibility factor for schizophrenia, but its mechanistic role in the disorder is unknown. Here we report that the gene encoding phosphodiesterase 4B (PDE4B) is disrupted by a balanced translocation in a subject diagnosed with schizophrenia and a relative with chronic psychiatric illness. The PDEs inactivate adenosine 3',5'-monophosphate (cAMP), a second messenger implicated in learning, memory, and mood. We show that DISC1 interacts with the UCR2 domain of PDE4B and that elevation of cellular cAMP leads to dissociation of PDE4B from DISC1 and an increase in PDE4B activity. We propose a mechanistic model whereby DISC1 sequesters PDE4B in resting cells and releases it in an activated state in response to elevated cAMP.

Background The importance of cerebrospinal fluid (CSF) diagnostics for psychiatry is growing. The CSF/blood albumin quotient (Q Alb ) is considered to be a measure of the blood–CSF barrier function. Recently, systematically higher Q Alb in males than in females was described in neurological patients. The aim of this study was to investigate whether a sex difference could also be detected in a well-characterized psychiatric cohort. Methods The patient cohort comprised 989 patients, including 545 females and 444 males with schizophreniform and affective syndromes who underwent CSF diagnostics, including Q Alb measurement. The basic CSF findings and antineuronal autoantibody data of this cohort have already been published. This re-analysis employed analysis of covariance with age correction for Q Alb mean values and chi 2 -testing for the number of increased age-corrected Q Alb levels to investigate sex differences in Q Alb . Results The Q Alb levels were elevated above reference levels by 18% across all patients, and a comparison between male and female patients revealed a statistically significant sex difference, with increased values in 26% of male patients and a corresponding rate of only 10% in female patients ( chi 2  = 42.625, p  < 0.001). The mean Q Alb values were also significantly higher in males (6.52 ± 3.69 × 10 –3 ) than in females (5.23 ± 2.56 × 10 –3 ; F  = 52.837, p  < 0.001). Discussion The main finding of this study was a significantly higher Q Alb level in male compared to female patients with psychiatric disorders, complementing previously described sex differences in neurological patient cohorts. This result indicates bias from some general factors associated with sex and could be partly explained by sex differences in body height, which is associated with spine length and thus a longer distance for CSF flow within the subarachnoid space down the spine from the occipital area to the lumbar puncture site in males compared to females. Hormonal influences caused by different estrogen levels and other sex-specific factors could also play a relevant role. The significance of the study is limited by its retrospective design, absence of a healthy control group, and unavailability of exact measures of spine length.

The role of changes in dopamine neuronal activity during the development of symptoms in affective disorders remains controversial. Here, we show that inactivation of NMDA receptors on dopaminergic neurons in adult mice led to the development of affective disorder-like symptoms. The loss of NMDA receptors altered activity and caused complete NMDA-insensitivity in dopamine-like neurons. Mutant mice exhibited increased immobility in the forced swim test and a decrease in social interactions. Mutation also led to reduced saccharin intake, however the preference of sweet taste was not significantly decreased. Additionally, we found that while mutant mice were slower to learn instrumental tasks, they were able to reach the same performance levels, had normal sensitivity to feedback and showed similar motivation to exert effort as control animals. Taken together these results show that inducing the loss of NMDA receptor-dependent activity in dopamine neurons is associated with development of affective disorder-like symptoms.

OBJECTIVE--To test the hypothesis that affective psychosis after childbirth is associated with an altered sensitivity to dopaminergic stimulation. DESIGN--Prospective study of pregnant women at high risk of developing an affective psychosis after childbirth. Clinical assessments in pregnancy and after delivery were made by using a semistructured interview (schedule for affective disorders and schizophrenia) and psychiatric illnesses were categorised according to operational criteria (research diagnostic criteria). SETTING--Obstetric and psychiatric departments in and around Greater London. SUBJECTS--29 pregnant women with a history of bipolar or schizoaffective psychosis and 47 control pregnant women. Of these, 16 from each group participated in a growth hormone challenge test and the results for 15 women in each group were analysed. INTERVENTIONS--On the fourth day postpartum women participating in the hormone challenge test were given a subcutaneous injection of a small dose (0.005 mg/kg) of the dopamine agonist apomorphine. MAIN OUTCOME MEASURES--Growth hormone secretion in response to apomorphine as an index of the functional state of hypothalamic dopamine receptors. RESULTS--Eight of the 15 women at risk of psychosis subsequently had a recurrence of illness (five bipolar, one schizomanic, and two major depressive illnesses); these women had significantly greater growth hormone responses to apomorphine than the seven at risk women who remained well and the 15 controls, and there were no significant differences between groups in average baseline growth hormone concentrations. The mean (SD) concentrations for women with recurrence, women at risk who remained well, and control women respectively were: average baseline concentrations 1.06 (1.14), 1.44 (1.39), and 0.90 (1.34) mU/l; peak increase in concentrations 13.68 (12.95), 3.46 (4.68), and 3.40 (3.83) mU/l (between group difference p less than 0.05); average increase in concentrations 6.74 (7.01), 1.78 (3.39), and 1.40 (2.05) mU/l (p less than 0.05). CONCLUSIONS--The onset of affective psychosis after childbirth was associated with increased sensitivity of dopamine receptors in the hypothalamus and possibly elsewhere in the brain. Such changes may be triggered by the sharp fall in circulating oestrogen concentrations after delivery.

Cultured human skin fibroblasts possess muscarinic receptors with the properties of specific binding, saturability, pharmacologic specificity, inhibition of norepinephrine-stimulated adenylate cyclase, and increased binding after incubation with an antagonist. The number of binding sites appears to be a stable characteristic of each cell line. We studied fibroblasts from 18 patients with a major affective disorder and found that they had a higher density of binding sites than cells from 12 normal controls. Fibroblasts from 18 relatives who had histories of major or minor affective disorder also had a higher density, and those from five normal relatives were similar to controls. These results, although still preliminary, suggest that increased cholinergic-receptor density may be associated with vulnerability to affective disorders in some familial cases. (N Engl J Med 1984; 311:225–30.) JANOWSKY et al. 1 have proposed that an imbalance between the cholinergic and noradrenergic systems has a key role in manic-depressive illness. These workers hypothesized that depression was associated with relatively increased cholinergic activity, and mania with increased noradrenergic activity. A number of clinical studies support the aspect of this hypothesis relating to cholinergic activity. 2 3 4 For example, physostigmine, which causes an increase in the levels of acetylcholine by inhibiting acetylcholinestcrasc, causes actively depressed patients to become more depressed and some euthymic patients to become transiently depressed. 5 Agricultural workers with histories of long exposure to anticholinesterase insecticides may have depressive episodes. 6 Conversely, . . .

The usefulness of polyunsaturated fatty acids on inflammatory, cardiovascular, and the nervous system was studied in the last decades, but the mechanisms underlying their benefic properties are still partially unknown. These agents seem to express their action on the membrane phospholipid composition and permeability and modulation of second messenger cascades. In psychiatry, the efficacy and tolerability of omega-3 fatty acids were investigated in several psychiatric disorders, including major depression, bipolar disorder, personality disorders, high-risk conditions to develop psychosis, attention-deficit hyperactivity disorder, and autism spectrum disorders. Initial findings in this field are promising, and some relevant questions need to be addressed. In particular, the effects of these agents on the main symptom dimensions have to be investigated in a trans-diagnostic perspective. The present systematic review is aimed to examine the available data on the efficacy of omega-3 fatty acids on domains of psychotic symptoms, affective symptoms, impulsivity, and aggressiveness, and harmful behaviors, and suicide risk.

Schizophrenia, bipolar disorder and major depressive disorder (MDD) have all been associated with aberrant blood cytokine levels; however, neither the pattern of cytokine alterations nor the impact of clinical status have been compared across disorders. We performed a meta-analysis of blood cytokines in acutely and chronically ill patients with these major psychiatric disorders. Articles were identified by searching the PubMed, PsycInfo and Web of Science, and the reference lists of these studies. Sixty-eight studies met the inclusion criteria (40 schizophrenia, 10 bipolar disorder and 18 MDD) for acutely ill patients. Forty-six studies met the inclusion criteria (18 schizophrenia, 16 bipolar disorder and 12 MDD) for chronically ill patients. Levels of two cytokines (interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α)), one soluble cytokine receptor (sIL-2R), and one cytokine receptor antagonist (IL-1RA) were significantly increased in acutely ill patients with schizophrenia, bipolar mania and MDD compared with controls ( P <0.01). Following treatment of the acute illness, IL-6 levels significantly decreased in both schizophrenia and MDD ( P <0.01); sIL-2R levels increased in schizophrenia; and IL-1RA levels in bipolar mania decreased. In chronically ill patients, the levels of IL-6 were significantly increased in schizophrenia, euthymic (but not depressed) bipolar disorder and MDD compared with controls ( P <0.01). The levels of IL-1β and sIL-2R were significantly increased in both chronic schizophrenia and euthymic bipolar disorder. Overall, there were similarities in the pattern of cytokine alterations in schizophrenia, bipolar disorder and MDD during acute and chronic phases of illness, raising the possibility of common underlying pathways for immune dysfunction. Effects of treatment on cytokines were more robust for schizophrenia and MDD, but were more frequently studied than for acute mania. These findings have important implications for our understanding of the pathophysiology and treatment of major psychiatric disorders.