Elevated serum thiobarbituric acid reactive substances in clinically symptomatic schizophrenic males

Uric acid levels in subjects with schizophrenia: A systematic review and meta-analysis

The association between schizophrenia (SZ) and uric acid (UA) levels has been suggested for many years, but without solid evidence. Therefore, we conducted a systematic review and meta-analysis of all case-control studies examining the serum and plasma UA levels in SZ subjects in comparison to those in healthy controls. Relevant studies published before October 29, 2018, were searched in the main electronic databases, and 17 studies were finally included into the meta-analysis after screening with the criteria. Our results revealed that there were no statistically significant differences of the UA levels between SZ subjects and healthy controls. Further subgroup analyses of the antipsychotic status reported the same finding. Subgroup analyses of clinical status showed that UA levels were decreased in subjects with first episode psychosis (FEP). The subgroup analyses of gender and ethnicity demonstrated that UA levels were decreased in male subjects and in Americans with SZ. Overall, these findings strengthen the clinical evidence that FEP is accompanied by increased oxidative stress response. Reduced UA levels may be a potential risk factor for SZ in male and in the Americans. However, whether there is a causal relationship between the reduced UA levels and the development of SZ deserves further investigation.

Studies on Haloperidol and Adjunctive α-Mangostin or Raw Garcinia mangostana Linn Pericarp on Bio-Behavioral Markers in an Immune-Inflammatory Model of Schizophrenia in Male Rats

Schizophrenia is a severe brain disorder that is associated with neurodevelopmental insults, such as prenatal inflammation, that introduce redox-immune-inflammatory alterations and risk for psychotic symptoms later in life. Nutraceuticals may offer useful adjunctive benefits. The aim of this study was to examine the therapeutic effects of Garcinia mangostana Linn (GML) and one of its active constituents, α-mangostin (AM), alone and as adjunctive treatment with haloperidol (HAL) on schizophrenia related bio-behavioral alterations in a maternal immune-activation (MIA) model. Sprague-Dawley dams were exposed to lipopolysaccharide (LPS) (n = 18) or vehicle (n = 3) on gestational days 15 and 16. Male offspring (n = 72) were treated from PND 52-66 with either vehicle, HAL (2 mg/kg), GML (50 mg/kg), HAL + GML, AM (20 mg/kg), or HAL + AM. Control dams and control offspring were treated with vehicle. In order to cover the mood-psychosis continuum, prepulse inhibition (PPI) of startle, open field test (locomotor activity), and the forced swim test (depressive-like behavior) were assessed on PND's 64-65, followed by assay of frontal-cortical lipid peroxidation and plasma pro-inflammatory cytokines, viz. interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α). MIA-induced deficits in sensorimotor gating were reversed by HAL and HAL + GML, but not GML and AM alone. MIA-induced depressive-like behavior was reversed by AM and GML alone and both in combination with HAL, with the combinations more effective than HAL. MIA-induced cortical lipid peroxidation was reversed by HAL and AM, with elevated IL-6 levels restored by GML, AM, HAL, and HAL + GML. Elevated TNF-α was only reversed by GML and HAL + GML. Concluding, prenatal LPS-induced psychotic- and depressive-like bio-behavioral alterations in offspring are variably responsive to HAL, GML, and AM, with depressive (but not psychosis-like) manifestations responding to GML, AM, and combinations with HAL. AM may be a more effective antioxidant than GML in vivo, although this does not imply an improved therapeutic response, for which trials are required.

Telomere length in subjects with schizophrenia, their unaffected siblings and healthy controls: Evidence of accelerated aging

Schizophrenia (SZ) is associated with broad burden. The clinical manifestations of SZ are related to pathophysiological alterations similar to what is seen in normal aging. Our aim was to evaluate the differences in telomere length (TL), a biomarker of cellular aging, in subjects with SZ (n=36), unaffected siblings (SB, n=36) and healthy controls (HC, n=47). SZ had shorter TL compared to HC, but no difference was found in SB comparing to SZ. These findings indicate that a pathological accelerated aging profile could be present in the course of SZ and further studies are needed to confirm TL as potential endophenotype, especially in at risk populations.

DNA Damage in Major Psychiatric Diseases

Human cells are exposed to exogenous insults and continuous production of different metabolites. These insults and unwanted metabolic products might interfere with the stability of genomic DNA. Recently, many studies have demonstrated that different psychiatric disorders show substantially high levels of oxidative DNA damage in the brain accompanied with morphological and functional alterations. It reveals that damaged genomic DNA may contribute to the pathophysiology of these mental illnesses. In this article, we review the roles of oxidative damage and reduced antioxidant ability in some vastly studied psychiatric disorders and emphasize the inclusion of treatment options involving DNA repair. In addition, while most currently used antidepressants are based on the manipulation of the neurotransmitter regulation in managing different mental abnormalities, they are able to prevent or reverse neurotoxin-induced DNA damage. Therefore, it may be plausible to target on genomic DNA alterations for psychiatric therapies, which is of pivotal importance for future antipsychiatric drug development.

Reliability of malondialdehyde as a biomarker of oxidative stress in psychological disorders

Despite very wide variations of malondialdehyde (MDA) concentrations in biological samples, it is still used as a biomarker of oxidative stress in clinical investigations. In the current perspective study, we aimed to summarize a number of critical analytical points for determination of MDA. Technical problems and controversial findings in healthy people and some psychiatric disorders reveal that the reliability of MDA as a biomarker of oxidative stress n eeds to be re-evaluated by experts.

Meta-analysis of oxidative stress in schizophrenia

BACKGROUND

Schizophrenia is associated with impaired antioxidant defense, including abnormal serum, plasma, and red blood cell (RBC) oxidative stress parameters. We performed a meta-analysis of these associations, considering the effect of clinical status and antipsychotic treatment after an acute exacerbation of psychosis.

METHODS

We identified articles by searching PubMed, PsychInfo, and Institute for Scientific Information, and the reference lists of identified studies.

RESULTS

Forty-four studies met the inclusion criteria. Total antioxidant status seemed to be a state marker, because levels were significantly decreased in cross-sectional studies of serum and plasma in first-episode psychosis (FEP) and significantly increased in longitudinal studies of antipsychotic treatment for acute exacerbations of psychosis (p < .01 for each). The RBC catalase and plasma nitrite seemed to be state-related markers, because levels in cross-sectional studies were significantly decreased in FEP (p < .01) and significantly increased in stable outpatients (p = .01). In contrast, RBC superoxide dismutase seemed to be a trait marker for schizophrenia, because levels in cross-sectional studies were significantly decreased in acutely relapsed inpatients, FEP, and stable outpatients (p < .01 for each).

CONCLUSIONS

Oxidative stress abnormalities in FEP suggest an effect that might be independent of antipsychotic medications. Although some parameters (total antioxidant status, RBC catalase, and plasma nitrite) might be state markers for acute exacerbations of psychosis, others (RBC superoxide dismutase) might be trait markers; however, more longitudinal studies are needed. Our findings suggest that oxidative stress might serve as a potential biomarker in the etiopathophysiology and clinical course of schizophrenia.

Effects of omega-3 dietary supplement in prevention of positive, negative and cognitive symptoms: a study in adolescent rats with ketamine-induced model of schizophrenia

Omega-3 has shown efficacy to prevent schizophrenia conversion in ultra-high risk population. We evaluated the efficacy of omega-3 in preventing ketamine-induced effects in an animal model of schizophrenia and its effect on brain-derived neurotrophic factor (BDNF). Omega-3 or vehicle was administered in Wistar male rats, both groups at the 30th day of life for 15days. Each group was split in two to receive along the following 7days ketamine or saline. Locomotor and exploratory activities, memory test and social interaction between pairs were evaluated at the 52nd day of life. Prefrontal-cortex, hippocampus and striatum tissues were extracted right after behavioral tasks for mRNA BDNF expression analysis. Bloods for serum BDNF were withdrawn 24h after the end of behavioral tasks. Locomotive was increased in ketamine-treated group compared to control, omega-3 and ketamine plus omega-3 groups. Ketamine group had fewer contacts and interaction compared to other groups. Working memory and short and long-term memories were significantly impaired in ketamine group compared to others. Serum BDNF levels were significantly higher in ketamine plus omega-3 group. There was no difference between groups in prefrontal-cortex, hippocampus and striatum for mRNA BDNF expression. Administration of omega-3 in adolescent rats prevents positive, negative and cognitive symptoms in a ketamine animal model of schizophrenia. Whether these findings are consequence of BDNF increase it is unclear. However, this study gives compelling evidence for larger clinical trials to confirm the use of omega-3 to prevent schizophrenia and for studies to reinforce the beneficial role of omega-3 in brain protection.

Serum levels of IL-6, IL-10 and TNF-α in patients with bipolar disorder and schizophrenia: differences in pro- and anti-inflammatory balance

OBJECTIVE

Previous reports suggest that cytokines act as potential mediators of the interaction between the immune and neuroendocrine systems, and that a proinflammatory state may be associated with bipolar disorder and schizophrenia. The aim is to compare cytokine levels in both disorders.

METHOD

Twenty euthymic bipolar disorder patients, 53 chronic stabilized schizophrenia patients and 80 healthy controls were recruited. Subjects were all non-smokers and non-obese. Cytokines TNF-α, IL-6, and IL-10 were examined by sandwich ELISA.

RESULTS

IL-6 levels were increased in schizophrenia patients when compared to controls (p < 0.0001) and euthymic bipolar disorder patients (p < 0.0001). IL-6 levels were no different in controls compared to euthymic bipolar disorder patients (p = 0.357). IL-10 was lower in controls compared to schizophrenia patients (p = 0.001) or to bipolar disorder patients (p = 0.004). There was no significant difference in TNF-α serum levels among the groups (p = 0.284). Gender-based classification did not significantly alter these findings, and no correlation was found between the antipsychotic dose administered and cytokine levels in patients with schizophrenia.

DISCUSSION

These findings evidence a chronic immune activation in schizophrenia. Bipolar disorder seems to present an episode-related inflammatory syndrome. Increased anti-inflammatory factor IL-10 in bipolar disorder and schizophrenia suggests different patterns of inflammatory balance between these two disorders. Results further support the need to investigate cytokines as possible biomarkers of disease activity or treatment response.

Similarities in serum oxidative stress markers and inflammatory cytokines in patients with overt schizophrenia at early and late stages of chronicity

Schizophrenia (SZ) is a debilitating neurodevelopmental disorder that strikes at a critical period of a young person's life. Its pathophysiology could be the result of deregulation of synaptic plasticity, with downstream alterations of inflammatory immune processes regulate by cytokines, impaired antioxidant defense and increased lipid peroxidation. The aim of this study was to examine serum oxidative stress markers and inflammatory cytokines in early and late phases of chronic SZ. Twenty-two patients at early stage (within first 10 years of a psychotic episode), 39 at late stage (minimum 10 years after diagnosis of SZ) and their respective matched controls were included. Each subject had 5 ml blood samples collected by venipuncture to examined thiobarbituric acid-reactive substances (TBARS), total reactive antioxidant potential (TRAP), protein carbonyl content (PCC), Interleukins 6 and 10 (IL-6, IL-10) and tumor necrosis factor alpha (TNF-alpha). TBARS, IL-6 and PCC levels were significantly higher in patients with SZ at early and late stages than in controls. There were no differences for TRAP and TNF-alpha levels in patients with SZ at early and late stages than in controls. IL-10 levels were decreased in patients at late stage and a decrease trend in early stage was found. Results provided evidence consistent with comparable biological markers across chronic SZ. The concept of biochemical staging proposed by others for bipolar disorder is not seen in this cohort of patients with SZ, at least for cytokines and oxidative stress markers. Our findings reinforce the need of assessment of individuals in ultra high risk to develop psychosis and first-episode population.

Neurobehavioral and genotoxic parameters of antipsychotic agent aripiprazole in mice

AIM

Aripiprazole is an antipsychotic agent to treat schizophrenia, which acts through dopamine D(2) partial agonism, serotonin 5-HT(1A) partial agonism and 5-HT(2A) antagonism. This study was designed to evaluate the neurobehavioral effects and genotoxic/mutagenic activities of the agent, as well as its effects on lipoperoxidation.

METHODS

Open field and inhibitory avoidance tasks were used. Thirty min before performing the behavioral tasks, adult male CF-1 mice were administered aripiprazole (1, 3 or 10 mg/kg, ip) once for the acute treatment, or the same doses for 5 d for the subchronic treatment. Genotoxic effects were assessed using comet assay in the blood and brain tissues. Mutagenic effects were evaluated using bone marrow micronucleus test. Lipoperoxidation was assessed with thiobarbituric acid reactive substances (TBARS).

RESULTS

Acute and subchronic treatments significantly decreased the number of crossing and rearing in the open field task. Acute treatment significantly increased the step-down latency for both the short- and long-term memory in the inhibitory avoidance task. Subchronic treatments with aripiprazole (3 and 10 mg/kg) caused significant DNA strain-break damage in peripheral blood but not in the brain. Mutagenic effect was not detected in the acute and subchronic treatments. Nor TBARS levels in the liver were affected.

CONCLUSION

Aripiprazole improved memory, but could impair motor activities in mice. The drug increased DNA damage in blood, but did not show mutagenic effects, suggesting that it might affect long-term genomic stability.

Quetiapine, olanzapine and haloperidol affect human plasma lipid peroxidation in vitro

OBJECTIVE

Oxidative injury in schizophrenia may be caused not only by pathophysiological processes but partly also by treatment with antipsychotics. The purpose of the present study was to examine and to compare the effects of quetiapine (QUE), olanzapine (OLA) and haloperidol (HAL), at final concentrations corresponding to doses used for treatment of acute episodes of schizophrenia, on plasma lipid peroxidation in vitro, measured by the level of thiobarbituric acid-reactive substances (TBARS).

METHODS

Blood from 30 healthy volunteers was collected into ACD (citric acid/citrate/dextrose) solution. The drugs in form of active substances were dissolved in 0.01% dimethyl sulfoxide, added to plasma at the final concentrations [QUE (175 and 275 ng/ml), OLA (20 and 40 ng/ml), HAL (4 and 20 ng/ml)] and incubated for 1 and 24 h at 37 °C. The level of TBARS was measured spectrophotometrically (according to the Rice-Evans method, 1991).

RESULTS

The comparative study in vitro showed that QUE causes a decrease in the TBARS level in plasma, whereas HAL increases the plasma TBARS level. After 24 h of incubation of plasma with QUE or HAL (at lower and higher concentrations),thedifferences in TBARS levels between the drugs were significant (p = 5.9 × 10⁻⁴, p = 2.2 × 10⁻⁵, respectively).

CONCLUSION

QUE and OLA, contrary to the prooxidative action of HAL, did not induce oxidative stress; moreover, QUE has antioxidant properties.

Bimodal distribution of polyunsaturated fatty acids in schizophrenia suggests two endophenotypes of the disorder

BACKGROUND

There is conflicting evidence of whether polyunsaturated fatty acids (PUFA) in red blood cells are bimodally distributed in schizophrenia. The purpose of this study was to examine the distribution of PUFA, as well as its links to plausible causal factors.

METHODS

A 16-week cohort study and a case-control study as part of a randomized controlled trial. Ninety-nine patients with DSM-IV schizophrenia, schizoaffective disorder, or schizophreniform disorder, aged 18 to 39, were consecutively included at admission to psychiatric departments of nine Norwegian hospitals. Fatty acids were measured in 97 of these patients and in 20 healthy control subjects. The primary outcome measure was the bimodality test statistic T, assessed by a χ(2) test of the likelihood of one or two normal distributions of PUFA.

RESULTS

At baseline, levels of polyunsaturated fatty acids were highly significantly bimodally distributed among patients. One third of patients constituted a group (low PUFA) who had PUFA levels at one fifth (p < .001) of those in high PUFA patients and healthy control subjects, which did not differ. Bimodality was mainly accounted for by docosahexaenoic acid and arachidonic acid. Bimodality was confirmed after 16 weeks. α-tocopherol was a robust predictor of PUFA at both occasions. Desaturase and elongase indexes differed between PUFA groups. Smoking, gender, antipsychotic medication, and dietary factors did not explain the bimodal distribution.

CONCLUSIONS

Red blood cell PUFA were bimodally distributed among acutely ill patients with schizophrenia and schizoaffective disorder. Endogenous deficiencies of redox regulation or synthesis of long-chain PUFA in the low PUFA group may explain our findings.

Increased annexin-V and decreased TNF-α serum levels in chronic-medicated patients with schizophrenia

Schizophrenia (SZ) is a chronic severe mental disorder. Increased inflammatory processes have been shown in acute and chronic SZ. Apoptotic processes may alter the neuronal network and are involved in the pathogenesis of several neurodegenerative diseases, such as SZ. Annexin-V seems to have a role on inhibition of pro-inflammatory activities during apoptosis. Tumor necrosis factor (TNF-alpha) is a cytokine involved in systemic inflammation and is a member of a group of cytokines which stimulate acute phase reactions. A chronic immune activation in SZ has been shown. The aim of this study was to compare annexin-V and TNF-alpha serum levels in chronic medicated patients with SZ and healthy controls. Thirty-eight outpatients from the HCPA Schizophrenia Program and 38 healthy controls were enrolled to this study protocol. Annexin-V and TNF-alpha serum levels were measured with ELISA. Serum annexin-V levels were significantly higher in patients with SZ than in controls (p<0.001) and TNF-alpha significantly lower (p<0.001). The present result of increased annexin-V and decreased serum levels of TNF-alpha compared to controls may be a result of the stabilization phase of psychosis and a reduction in metabolic brain aggression. In this complex picture, increased levels of annexin-V and decreased levels of TNF-alpha in our sample would be explained by illness stability and chronic treatment. Our findings support the hypothesis of a state dependant process of inflammation in SZ. Further prospective studies to clarify the findings described in this paper are needed.

Oxidative stress in schizophrenia

Increasing evidence indicates that oxidative damage exists in schizophrenia. Available literature about possible mechanisms of oxidative stress induction was reviewed. Furthermore, possibilities of measuring biomarkers of schizophrenia outside the central nervous system compartment, their specificity for different types of schizophrenia and potential therapeutic strategies to prevent oxidative injuries in schizophrenia were discussed. Data were extracted from published literature found in Medline, Embase, Biosis, Cochrane and Web of Science, together with hand search of references. Search terms were: schizophrenia, oxidative stress, antipsychotics, antioxidants and fatty acids. Finding a sensitive, specific and non invasive biomarker of schizophrenia, which could be measured in peripheral tissue, still stays an important task. Antioxidant enzymes, markers of lipid peroxidation, oxidatively modified proteins and DNA are most commonly used. As it considers the supplemental therapy, according to our meta-analysis vitamin E could potentially improve tardive dyskinesia, while for the effect of therapy with polyunsaturated fatty acids there is no clear evidence. Oxidative stress is a part of the pathology in schizophrenia and appears as a promising field to develop new therapeutic strategies. There is a need for well designed, placebo controlled trials with supplementation therapy in schizophrenia.

Serum brain-derived neurotrophic factor and clozapine daily dose in patients with schizophrenia: a positive correlation

Brain-derived neurotrophic factor (BDNF) plays a critical role in neurodevelopment and neuroplasticity. Altered BDNF signaling is thought to contribute to the pathogenesis of schizophrenia (SZ) especially in relation to cognitive deficits. Clozapine (CLZ) has been shown a beneficial effect on cognition in SZ in some studies and a detrimental effect in others. To examine serum BDNF, two groups of chronically medicated DSM-IV SZ patients (n=44), on treatment with clozapine (n=31) and typical antipsychotics (n=13) had 5ml blood samples collected by venipuncture. Serum BDNF levels were significantly correlated with CLZ daily dose (r=0.394, p=0.028), but not with typical antipsychotic daily dose (r=0.208, p=0.496). This study suggests that serum BDNF levels are correlated with CLZ daily dose, and this may lead to the cognitive enhancement as seen in patients with SZ under CLZ. Despite the strong evidence that chronic administration of CLZ is effective for patients with SZ, it is still unknown whether atypical antipsychotic drugs regulate BDNF expression. Serum BDNF levels concentration in SZ merits further investigations with regard to the role of neurotrophins in the cognitive response to treatment with CLZ and other atypical antipsychotics.

Evaluation of carotenoid level in schizophrenic patients using non-invasive measurement

Free radicals are produced as part of the body immune response triggered by exogenous oxidants. In excess, they impair antioxidant defence system and cause oxidative stress. Antioxidants are hypothesised as antidotes to counteract oxidative stress and improve immune function. Carotenoids serve as a reliable indicator of overall antioxidant level in humans. This study investigated the possible relationship of carotenoid antioxidant levels in schizophrenia. A total of 351 schizophrenic subjects from Hospital Bahagia Ulu Kinta, Malaysia and 247 healthy controls were recruited. Subjects' skin carotenoid levels were measured using a non-invasive technique, Raman spectroscopy. The results showed significant (P<0.01) reduction of carotenoid level in patient compared to healthy controls, suggesting higher levels of oxidative stress in schizophrenia. Comparison between gender, age, subtypes, antipsychotic drug treatments, and duration of illness was investigated, but none was significantly associated with carotenoid score. Antipsychotics were suggested to be the possible causes of reduced antioxidant level in schizophrenia.

Lipid peroxidation in patients with schizophrenia

AIMS

There is evidence that dysregulation of free radicals metabolism associated with abnormal activities of antioxidative enzymes in schizophrenia can lead to lipid peroxidation in plasma, erythrocytes, blood platelets and cerebrospinal fluid. Injury to neurons in schizophrenia may affect their function, i.e. membrane transport, impairment of energy production in mitochondria, changes in membrane phospholipid composition, alteration of receptors and transporters as well as neurotransmission. The purpose of the present study was to assess the total antioxidant capacity (TAC) and lipid peroxidation (expressed as the level of thiobarbituric acid reactive substances [TBARS]) in plasma from schizophrenic patients taking olanzapine or risperidone. The level of TBARS estimated according to the Rice-Evans method and TAC ([ABTS; 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation decolorization assay]) in plasma from schizophrenic patients (DSM-IV criteria for schizophrenia, n = 30, age 18-36) taking olanzapine or risperidone and from healthy volunteers (n = 30) were measured.

METHODS

The level of TBARS in plasma from healthy volunteers after incubation with olanzapine or risperidone was also estimated.

RESULTS

Significantly lower plasma TAC (P < 0.05) and significantly increased level of TBARS (P < 0.001) in schizophrenic patients were observed. The in vitro study showed that after olanzapine or risperidone (at final concentrations corresponding to doses used in acute episodes of schizophrenia treatment) no changes of plasma lipid peroxidation were found (P > 0.05). The obtained results indicate that the pro-oxidant disturbances occur in schizophrenic patients (acute episode) taking stable doses of olanzapine or risperidone.

CONCLUSION

It seems that second-generation antipsychotics (olanzapine and risperidone) are not responsible for increase of plasma lipid peroxidation.

Effects of N-acetylcysteine on substance use in bipolar disorder: A randomised placebo-controlled clinical trial

OBJECTIVE

To evaluate the effect of N-acetylcysteine (NAC) on substance use in a double-blind, placebo-controlled trial of NAC in bipolar disorder. It is hypothesised that NAC will be superior to placebo for reducing scores on the Clinical Global Impressions scale for Substance Use (CGI-SU).

METHODS

Participants were randomised to a 6-months of treatment with 2 g/day NAC (n = 38) or placebo (n = 37). Substance use was assessed at baseline using a Habits instrument. Change in substance use was assessed at regular study visits using the CGI-SU.

RESULTS

Among the 75 participants 78.7% drank alcohol (any frequency), 45.3% smoked tobacco and 92% consumed caffeine. Other substances were used by fewer than six participants. Caffeine use was significantly lower for NAC-treated participants compared to placebo at week 2 of treatment but not at other study visits.

CONCLUSIONS

NAC appeared to have little effect on the participants who were using substances. A larger study on a substance-using population will be necessary to determine if NAC may be a useful treatment for substance use.

Oxidative mechanisms in schizophrenia and their relationship with illness subtype and symptom profile

AIM

The aim of the present study was to investigate the differences in the antioxidant-oxidant balance (AO-OB) between schizophrenic patients and healthy individuals and to explore the relationship of AO-OB with illness subtypes and symptom profiles.

METHODS

After a 15-day drug-free period, schizophrenia patients (n = 50) in a clinical sample, and age- and sex-matched healthy subjects (n = 49) were enrolled. Total antioxidant potentials (TAOP) and total peroxide levels (TPEROX) of all participants were measured and the oxidative stress index (OSI) was calculated. The assessment included structured measurements, including the Positive and Negative Syndrome Scale (PANSS), and the Brief Psychiatric Rating Scale (BPRS).

RESULTS

TAOP had a significant positive correlation with age at onset of schizophrenia (P = 0.013), a negative correlation with the PANSS negative subscale scores (P = 0.008), a negative correlation with the PANSS total scores (P < 0.001), and a significant negative correlation with BPRS scores (P = 0.001). OSI had a significant negative correlation with age at onset (P = 0.046) and a significant positive correlation with PANSS negative subscale (P = 0.015). A multiple regression model indicated a significant linear combination of age, gender, duration of illness, subtype of schizophrenia, and PANSS scores, in which only the subtype of schizophrenia made a statistically significant contribution to predicting mean OSI (F[5,35] = 2.44, P = 0.04).

CONCLUSION

Several parameters in the pathogenesis of schizophrenia, such as age of onset, level of negative symptoms, and subtype of illness, but not the presence of the illness itself, are associated with the level of oxidative stress.

Effects of N-acetylcysteine on substance use in bipolar disorder: a randomised placebo-controlled clinical trial

OBJECTIVE

To evaluate the effect of N-acetylcysteine (NAC) on substance use in a double-blind, placebo-controlled trial of NAC in bipolar disorder. It is hypothesised that NAC will be superior to placebo for reducing scores on the Clinical Global Impressions scale for Substance Use (CGI-SU).

METHODS

Participants were randomised to 6-months of treatment with 2 g/day NAC (n = 38) or placebo (n = 37). Substance use was assessed at baseline using the Habits instrument. Change in substance use was assessed at regular study visits using the CGI-SU.

RESULTS

Amongst the 75 participants 78.7% drank alcohol (any frequency), 45.3% smoked tobacco and 92% consumer caffeine. Other substances were used by fewer than six participants. Caffeine use was significantly lower for NAC-treated participants compared with placebo at week 2 of treatment but not at other study visits.

CONCLUSION

NAC appeared to have little effect on substance use in this population. A larger study on a substance using population will be necessary to determine if NAC may be a useful treatment for substance use.

Serum levels of brain-derived neurotrophic factor and thiobarbituric acid reactive substances in chronically medicated schizophrenic patients: a positive correlation

OBJECTIVE

The neurotrophins, antioxidant enzymes and oxidative markers have reciprocal interactions. This report verified in chronically stable medicated schizophrenic patients whether there are correlations between the serum levels of superoxide dismutase, a key enzyme in the antioxidant defense, thiobarbituric acid reactive substances, a direct index of lipid peroxidation, and brain-derived neurotrophic factor, the most widely distributed neurotrophin.

METHOD

Sixty DSM-IV schizophrenic patients were included (43 males, 17 females). Mean age was 34.7 +/- 10.8 years, mean age at first episode was 19.8 +/- 7.9 years, and mean illness duration was 14.9 +/- 8.5 years. Each subject had a blood sample collected for the determination of serum levels of brain-derived neurotrophic factor, thiobarbituric acid reactive substances and superoxide dismutase.

RESULTS

Brain-derived neurotrophic factor levels showed a positive correlation with thiobarbituric acid reactive substances levels (r = 0.333, p = 0.009). Brain-derived neurotrophic factor levels were not correlated with superoxide dismutase levels (r = - 0.181, p = 0.166), and superoxide dismutase levels were not correlated with thiobarbituric acid reactive substances levels (r = 0.141, p = 0.284).

CONCLUSIONS

The positive correlation between brain-derived neurotrophic factor and thiobarbituric acid reactive substances suggests the need of further investigation on intracellular interactions of neurotrophins, antioxidant enzymes and oxidative markers. In addition, this opens a venue for investigation on treatments for the prevention of neurotoxicity along the course of schizophrenia.

Elevated serum superoxide dismutase and thiobarbituric acid reactive substances in different phases of bipolar disorder and in schizophrenia

There is an increasing body of evidence suggesting that oxidative stress may play a role in the pathophysiology of both schizophrenia (SZ) and bipolar disorder (BD).

METHODS

We compared the antioxidant enzyme, serum superoxide dismutase (SOD) and the lipid peroxidation product, thiobarbituric acid reactive substances (TBARS) as assessed in depressed (N=21), manic (N=32) and euthymic (N=31) bipolar patients, and in chronically medicated patients with schizophrenia (N=97), all fulfilling DSM-IV diagnostic criteria, and a group of healthy controls (N=32).

RESULTS

Serum SOD (U/mg protein) activity was significantly increased (p<0.001) in manic (7.44+/-3.88) and depressed (6.12+/-4.64) BD patients and SZ (9.48+/-4.51) when compared to either controls (1.81+/-0.63) or euthymic (2.75+/-1.09) BD patients. TBARS (mol/L) levels were significantly higher in the SZ group (4.95+/-1.56, p=0.016), bipolar euthymic (6.36+/-1.46, p<0.001), bipolar manic (7.54+/-1.74, p<0.001), and bipolar depressed patients (5.28+/-1.54, p=0.028) compared to controls (3.96+/-1.51).

DISCUSSION

Our findings show increased SOD activity in SZ, as well as in depressed and manic bipolar patients, but not in euthymic BD subjects. This suggests a dysregulation in oxidative defenses in both disorders. It is likely that such changes reflect state changes in bipolar disorder. It is possible that this is a compensatory response to the oxidative stress that occurs in the acute phase of bipolar episodes. TBARS results show increases in lipid peroxidation in mania. TBARS levels in SZ and in euthymic as well as depressed individuals with BD were higher than in controls. This suggests persistent increases in SZ, which may reflect ongoing symptomatology or treatment, and a state dependent gradient in BD, with greatest oxidative stress in mania. These data support oxidative biology as both a key component of the pathophysiology of both BD and SZ, and the use of agents that modulate oxidative biology as a promising avenue for intervention in both disorders.

Serum levels of brain-derived neurotrophic factor in schizophrenia on a hypocaloric diet

Dietary factors influence BDNF in animal studies, but there is no comparable data in clinical populations. We examined the effect of a dietary intervention on BDNF serum levels in 67 DSM-IV schizophrenic outpatients (51 males and 16 females). Two groups were assessed in a cross-sectional study: one on a hypocaloric diet (HD) and the other not on a hypocaloric diet. Weight, height and BMI data were collected concurrently with 5-ml blood sampling of each subject. BDNF levels were measured with a sandwich-ELISA. The blood sample was obtained a minimum of one month after the exposure to dietary intervention. Serum BDNF levels were significantly higher in patients on the HD (p=0.023). Additional research examining the interaction among patterns of nutritional food behavior and underlying physiopathology may result in insights upon which evidence-based decisions regarding dietary interventions can be made in people identified with major psychiatric disorders, such as schizophrenia.

Decreased serum neurotrophin 3 in chronically medicated schizophrenic males

There is evidence that major psychiatric disorders such as schizophrenia (SZ) are associated with deregulation of synaptic plasticity with downstream alterations of neurotrophins. NT3 is an important neurotrophin in the central nervous system, and performs key biological functions, such as promoting the survival, differentiation, and plasticity of neurons. NT3 has a central role in the early neuronal development; enhancing the survival of dopaminergic neurons, suggesting possible involvement in the physiopathology of dopamine related neuropsychiatric disorders such as SZ. Variations in the NT3 gene increase the risk of SZ. Three groups of chronically medicated DSM-IV patients with SZ, on treatment with clozapine (n=12), haloperidol (n=12), risperidone (n=12) and 10 healthy controls had 5 ml blood samples collected by venipuncture. NT3 serum levels were assessed using sandwich-ELISA and were significantly lower in SZ patients (p<0.005) when compared to either controls. These findings suggest that the NT3 signaling system may play a role in the pathophysiology of SZ and might be related to the course of illness or to treatment variables. Longitudinal studies are warranted.