Recent advances in treating cognitive impairment in schizophrenia

Exercise as an intervention for first-episode psychosis: a feasibility study

AIM

Exercise can improve psychiatric symptoms, neurocognitive functioning and physical health in schizophrenia. However, the effects in early psychosis have not been explored. This study aimed to assess the feasibility of an exercise intervention for early psychosis and to determine if it was associated with changes in physical and mental health.

METHODS

Thirty-one patients with first-episode psychosis (FEP) were recruited from early intervention services to a 10-week exercise intervention. The intervention group received individualized training programmes, aiming to achieve ≥90 min of moderate-to-vigorous activity each week, using exercise programmes tailored to individual preferences and needs. A comparison FEP sample from the same services (n = 7) received treatment as usual.

RESULTS

Rates of consent and retention in the exercise group were 94% and 81%, respectively. Participants achieved an average of 107 min of moderate-to-vigorous exercise per week. Positive and Negative Syndrome Scale total scores reduced by 13.3 points after 10 weeks of exercise, which was significantly greater than the treatment as usual comparison group (P = 0.010). The greatest differences were observed in negative symptoms, which reduced by 33% in the intervention group (P = 0.013). Significant improvements were also observed in psychosocial functioning and verbal short-term memory. Increases in cardiovascular fitness and processing speed were positively associated with the amounts of exercise achieved by participants.

CONCLUSION

Individualized exercise training could provide a feasible treatment option for improving symptomatic, neurocognitive and metabolic outcomes in FEP.

A systematic review of physical activity policy recommendations and interventions for people with mental health problems in Sub-Saharan African countries

Introduction

There is a need for interventions to address the escalating mental health burden in Sub-Saharan Africa (SSA). Implementation of physical activity (PA) within the rehabilitation of people with mental health problems (PMHP) could reduce the burden and facilitate recovery. The objective of the current review was to explore (1) the role of PA within mental health policies of SSA countries, and (2) the current research evidence for PA to improve mental health in SSA.

Methods

We screened the Mental Health Atlas and MiNDbank for mental health policies in SSA countries and searched PubMed for relevant studies on PA in PMHP in SSA.

Results

Sixty-nine percent (=33/48) of SSA countries have a dedicated mental health policy. Two of 22 screened mental health policies included broad physical activity recommendations. There is clear evidence for the role of PA in the prevention and rehabilitation of depression in SSA.

Conclusion

Despite the existing evidence, PA is largely a neglected rehabilitation modality in the mental health care systems of SSA. Continued education of existing staff, training of specialized professionals and integration of PA for mental health in public health awareness programs are needed to initiate and improve PA programs within the mental health care systems of SSA.

Motivating factors and barriers towards exercise in severe mental illness: a systematic review and meta-analysis

Exercise can improve clinical outcomes in people with severe mental illness (SMI). However, this population typically engages in low levels of physical activity with poor adherence to exercise interventions. Understanding the motivating factors and barriers towards exercise for people with SMI would help to maximize exercise participation. A search of major electronic databases was conducted from inception until May 2016. Quantitative studies providing proportional data on the motivating factors and/or barriers towards exercise among patients with SMI were eligible. Random-effects meta-analyses were undertaken to calculate proportional data and 95% confidence intervals (CI) for motivating factors and barriers toward exercise. From 1468 studies, 12 independent studies of 6431 psychiatric patients were eligible for inclusion. Meta-analyses showed that 91% of people with SMI endorsed 'improving health' as a reason for exercise (N = 6, n = 790, 95% CI 80-94). Among specific aspects of health and well-being, the most common motivations were 'losing weight' (83% of patients), 'improving mood' (81%) and 'reducing stress' (78%). However, low mood and stress were also identified as the most prevalent barriers towards exercise (61% of patients), followed by 'lack of support' (50%). Many of the desirable outcomes of exercise for people with SMI, such as mood improvement, stress reduction and increased energy, are inversely related to the barriers of depression, stress and fatigue which frequently restrict their participation in exercise. Providing patients with professional support to identify and achieve their exercise goals may enable them to overcome psychological barriers, and maintain motivation towards regular physical activity.

The Novel, Nicotinic Alpha7 Receptor Partial Agonist, BMS-933043, Improves Cognition and Sensory Processing in Preclinical Models of Schizophrenia

The development of alpha7 nicotinic acetylcholine receptor agonists is considered a promising approach for the treatment of cognitive symptoms in schizophrenia patients. In the present studies we characterized the novel agent, (2R)-N-(6-(1H-imidazol-1-yl)-4-pyrimidinyl)-4'H-spiro[4-azabicyclo[2.2.2]octane-2,5'-[1,3]oxazol]-2'-amine (BMS-933043), in vitro and in rodent models of schizophrenia-like deficits in cognition and sensory processing. BMS-933043 showed potent binding affinity to native rat (Ki = 3.3 nM) and recombinant human alpha7 nicotinic acetylcholine receptors (Ki = 8.1 nM) and agonist activity in a calcium fluorescence assay (EC50 = 23.4 nM) and whole cell voltage clamp electrophysiology (EC50 = 0.14 micromolar (rat) and 0.29 micromolar (human)). BMS-933043 exhibited a partial agonist profile relative to acetylcholine; the relative efficacy for net charge crossing the cell membrane was 67% and 78% at rat and human alpha7 nicotinic acetylcholine receptors respectively. BMS-933043 showed no agonist or antagonist activity at other nicotinic acetylcholine receptor subtypes and was at least 300 fold weaker at binding to and antagonizing human 5-HT3A receptors (Ki = 2,451 nM; IC50 = 8,066 nM). BMS-933043 treatment i) improved 24 hour novel object recognition memory in mice (0.1-10 mg/kg, sc), ii) reversed MK-801-induced deficits in Y maze performance in mice (1-10 mg/kg, sc) and set shift performance in rats (1-10 mg/kg, po) and iii) reduced the number of trials required to complete the extradimensional shift discrimination in neonatal PCP treated rats performing the intra-dimensional/extradimensional set shifting task (0.1-3 mg/kg, po). BMS-933043 also improved auditory gating (0.56-3 mg/kg, sc) and mismatch negativity (0.03-3 mg/kg, sc) in rats treated with S(+)ketamine or neonatal phencyclidine respectively. Given this favorable preclinical profile BMS-933043 was selected for further development to support clinical evaluation in humans.

Gaps in understanding health and engagement with healthcare providers across common long-term conditions: a population survey of health literacy in 29,473 Danish citizens

OBJECTIVES

To (1) quantify levels of subjective health literacy in people with long-term health conditions (diabetes, cardiovascular disease, chronic obstructive pulmonary disease, musculoskeletal disorders, cancer and mental disorders) and compare these to levels in the general population and (2) examine the association between health literacy, socioeconomic characteristics and comorbidity in each long-term condition group.

DESIGN

Population-based survey in the Central Denmark Region (n=29,473).

MAIN OUTCOME MEASURES

Health literacy was measured using two scales from the Health Literacy Questionnaire (HLQ): (1) Ability to understand health information and (2) Ability to actively engage with healthcare providers.

RESULTS

People with long-term conditions reported more difficulties than the general population in understanding health information and actively engaging with healthcare providers. Wide variation was found between disease groups, with people with cancer having fewer difficulties and people with mental health disorders having more difficulties in actively engaging with healthcare providers than other long-term condition groups. Having more than one long-term condition was associated with more difficulty in engaging with healthcare providers and understanding health information. People with low levels of education had lower health literacy than people with high levels of education.

CONCLUSIONS

Compared with the general population, people with long-term conditions report more difficulties in understanding health information and engaging with healthcare providers. These two dimensions are critical to the provision of patient-centred healthcare and for optimising health outcomes. More effort should be made to respond to the health literacy needs among individuals with long-term conditions, multiple comorbidities and low education levels, to improve health outcomes and to reduce social inequality in health.

Cognitive function, plasma MnSOD activity, and MnSOD Ala-9Val polymorphism in patients with schizophrenia and normal controls

Excessive reactive oxygen species are thought to produce oxidative damage that underlies neurodegeneration and cognitive impairment in several disorders including schizophrenia. The functional Ala-9Val polymorphism of the mitochondrial enzyme manganese superoxide dismutase (MnSOD), which detoxifies superoxide radicals to hydrogen peroxide, has been associated with schizophrenia. However, no study has reported its role in cognitive deficits of schizophrenia as mediated through MnSOD activity. We recruited 923 schizophrenic inpatients and 566 healthy controls and compared them on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), plasma MnSOD activity, and the MnSOD Ala-9Val polymorphism. We assessed patient psychopathology using the Positive and Negative Syndrome Scale. We showed that the MnSOD Ala-9Val polymorphism may not contribute directly to the susceptibility to schizophrenia. The Ala variant was associated with worse attention performance among chronic schizophrenic patients but not among normal controls. Plasma MnSOD activity was significantly decreased in patients compared with that in normal controls. Moreover, MnSOD activity among the schizophrenic Ala allele carriers was correlated with the degree of cognitive impairments, especially attention and RBANS total score. We demonstrated an association between the MnSOD Ala-9Val variant and poor attention in schizophrenia. The association between higher MnSOD activity and cognitive impairment in schizophrenia is dependent on the MnSOD Ala-9Val polymorphism.

Molecular Docking studies of D2 Dopamine receptor with Risperidone derivatives

In this work, 3D model of D2 dopamine receptor was determined by comparative homology modeling program MODELLER. The computed model's energy was minimized and validated using PROCHECK and Errat tool to obtain a stable model structure and was submitted in Protein Model Database (PMDB-ID: PM0079251). Stable model was used for molecular docking against Risperidone and their 15 derivatives using AutoDock 4.2, which resulted in energy-based descriptors such as Binding Energy, Ligand Efficiency, Inhib Constant, Intermol energy, vdW + Hbond + desolv Energy, Electrostatic Energy, Total Internal Energy and Torsional Energy. After that, we have built quantitative structure activity relationship (QSAR) model, which was trained and tested on Risperidone and their 15 derivatives having activity value pKi in µM. For QSAR modeling, Multiple Linear Regression model was engendered using energy-based descriptors yielding correlation coefficient r2 of 0.513. To assess the predictive performance of QSAR models, different cross-validation procedures were adopted. Our results suggests that ligand-receptor binding interactions for D2 employing QSAR modeling seems to be a promising approach for prediction of pKi value of novel antagonists against D2 receptor.

Pharmacological Interventions for the MATRICS Cognitive Domains in Schizophrenia: What's the Evidence?

Schizophrenia is a disabling, chronic psychiatric disorder with a prevalence rate of 0.5-1% in the general population. Symptoms include positive (e.g., delusions, hallucinations), negative (e.g., blunted affect, social withdrawal), as well as cognitive symptoms (e.g., memory and attention problems). Although 75-85% of patients with schizophrenia report cognitive impairments, the underlying neuropharmacological mechanisms are not well understood and currently no effective treatment is available for these impairments. This has led to the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) initiative, which established seven cognitive domains that are fundamentally impaired in schizophrenia. These domains include verbal learning and memory, visual learning and memory, working memory, attention and vigilance, processing speed, reasoning and problem solving, and social cognition. Recently, a growing number of studies have been conducted trying to identify the underlying neuropharmacological mechanisms of cognitive impairments in schizophrenia patients. Specific cognitive impairments seem to arise from different underlying neuropharmacological mechanisms. However, most review articles describe cognition in general and an overview of the mechanisms involved in these seven separate cognitive domains is currently lacking. Therefore, we reviewed the underlying neuropharmacological mechanisms focusing on the domains as established by the MATRICS initiative which are considered most crucial in schizophrenia.

Interleukin 18 and cognitive impairment in first episode and drug naïve schizophrenia versus healthy controls

Alterations in the inflammatory and immune systems have been documented to occur from the earliest stages of schizophrenia, and have been associated with neurodevelopmental changes. Cognitive impairment is a core feature in the pathology of schizophrenia, and recent studies showed a significant increase in serum IL-18 in schizophrenia, and a putative role of IL-18 in neuroprogression and thus neurocognitive defects. The purpose of this study was to examine the association of IL-18 with cognitive deficits in schizophrenia. We recruited 77 first episode and drug naïve schizophrenic patients and 75 healthy control subjects and examined the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and serum IL-18 in both groups. Schizophrenic symptoms were assessed using the positive and negative syndrome scale (PANSS). We found that IL-18 levels were non-significantly higher in patients than controls (206.0±92.9 pg/ml vs 193.2±41.8 pg/ml, p=0.28). Cognitive scores on the RBANS and nearly all of its five subscales (all p<0.05) except for the Visuospatial/Constructional index (p>0.05) were significantly lower in schizophrenic patients than normal controls. For the patients, IL-18 was positively associated with the Visuospatial/Constructional domain of cognitive deficits in schizophrenia. Our findings suggest that cognitive deficits occur during the acute stage of a schizophrenic episode, and IL-18 may be involved in Visuospatial/Constructional deficits of these patients.

An Overview of Cognitive Remediation Therapy for People with Severe Mental Illness

Cognitive remediation refers to nonpharmacological methods of improving cognitive function in people with severe mental disorders. Cognitive remediation therapy (CRT) can be delivered via computerised programs, of varying length and complexity, or can be undertaken one-on-one by a trained clinician. There has been a considerable interest in cognitive remediation, driven by recognition that cognitive deficits are a major determinant of outcome in people with severe, chronic mental illnesses. CRT has been shown to be effective, especially if combined with vocational rehabilitation.

Anticholinergics in the era of atypical antipsychotics: short-term or long-term treatment?

Anticholinergic agents are usually prescribed to prevent or treat antipsychotic-induced extrapyramidal symptoms. Their long-term benefits are questionable and they carry diverse adverse effects, including cognitive impairment and worsening of tardive dyskinesia. This literature review explores the impact of anticholinergic medication discontinuation on movement disorders, cognition and psychopathology in patients receiving antipsychotics. Medline, Embase and PsycInfo were searched from 1950 to July 2011 using "cessation /withdrawal /discontinuation /stopping" with "anticholinergic*" or "antiparkinson*" and "neuroleptic*" or "antipsychotic*". Additional articles were obtained by searching the bibliographies of relevant references. Earlier studies of anticholinergic agent discontinuation in patients receiving first-generation antipsychotics reported relapse rates of extrapyramidal symptoms between 4% and 80%, reflecting the heterogeneity of the studies. Two recent studies of patients prescribed second-generation antipsychotics obtained relapse rates of 4% and 33%. Some studies suggest improvement in tardive dyskinesia with cessation of anticholinergics. Four studies examined the effects of anticholinergic agent discontinuation on cognition and all observed an improvement post-discontinuation. Changes in symptoms of schizophrenia with anticholinergic discontinuation are conflicting, with more recent studies suggesting an improvement. Given their questionable benefit with continued use, clinicians should consider a gradual withdrawal of anticholinergic agents in stable patients receiving antipsychotics.

Plasma total antioxidant status and cognitive impairments in schizophrenia

Oxidative stress-induced damage to neurons may contribute to cognitive deficits during aging and in neurodegenerative disorders. Schizophrenia has a range of cognitive deficits that may evolve from oxidative stress, and this study examines this association of oxidative stress with cognitive deficits in schizophrenia. We recruited 296 chronic schizophrenia patients and 181 healthy control subjects and examined the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and plasma total antioxidant status (TAS) in both groups. Schizophrenia symptoms were assessed using the positive and negative syndrome scale (PANSS). Our results showed that TAS levels were significantly lower in patients than controls (179.6 ± 81.0 U/ml vs. 194.8 ± 46.0 U/ml, p<0.05). Cognitive scores on the RBANS and nearly all of its five subscales (all p<0.001) except for the Visuospatial/Constructional index (p>0.05) were significantly lower in schizophrenia patients than normal controls. For the patients, TAS was inversely associated with some domains of cognitive deficits in schizophrenia, such as Attention and Immediate Memory. Our findings suggest that oxidative stress may be involved in the pathophysiology of schizophrenia, and its associated cognitive impairment.

Genetic variation in Hyperpolarization-activated cyclic nucleotide-gated channels and its relationship with neuroticism, cognition and risk of depression

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are encoded by four genes (HCN1–4) and, through activation by cyclic AMP (cAMP), represent a point of convergence for several psychosis risk genes. On the basis of positive preliminary data, we sought to test whether genetic variation in HCN1–4 conferred risk of depression or cognitive impairment in the Generation Scotland: Scottish Family Health Study. HCN1, HCN2, HCN3, and HCN4 were genotyped for 43 haplotype-tagging SNPs and tested for association with DSM-IV depression, neuroticism, and a battery of cognitive tests assessing cognitive ability, memory, verbal fluency, and psychomotor performance. No association was found between any HCN channel gene SNP and risk of depression, neuroticism, or on any cognitive measure. The current study does not support a genetic role for HCN channels in conferring risk of depression or cognitive impairment in individuals from the Scottish population.

[Schizophrenia, psychotropic drugs and cognition]

The robust and specific associations between cognitive abilities and the functional prognosis of patients suffering from schizophrenia lead to a major concern for cognitive impairment in this disorder. Among the strategies considered to correct or enhance cognition in schizophrenia, drugs hold a pivotal place. Evidently, antipsychotic drugs, which are inextricable from patients' management, have generated considerable scrutiny in this topic. This paper first aims to outline the current views on the impact of antipsychotic drugs in schizophrenia. The distinction between conventional and atypical drugs is reminded in order to more precisely review existing data comparing the impact of these two types of molecules on cognitive impairment. More specifically, an elementary framework is proposed to facilitate the recognition of methodological flaws and offer a critical examination of previous findings. It emerges subsequently that differences between atypical and conventional drugs appear far less contrasted than initially suggested. Also, atypical antipsychotics compose a disparate pharmacological class and much clarification could be obtained by differentiating the individual effects of these molecules rather than considering them as a group. Finally, the relevance of these cognitive measures is also considered. In particular, we address alternative measures closer to real life situations as well as the growing interest in the broad field of social cognition. A last part of this article deals with strategies relying on adjunctive therapies. The fairly modest results obtained with these approaches is evoked and briefly reviewed.

The MATRICS consensus cognitive battery (MCCB): co-norming and standardization in Spain

The MATRICS Consensus Cognitive Battery (MCCB), developed by the National Institute of Mental Health (NIMH) Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) initiative, has been recommended as the standard battery for clinical trials of cognition-enhancing interventions for schizophrenia. Normative data for the MCCB has been previously obtained in the U.S. Extrapolation of these normative data to different countries may be problematic due to the translation of the different tests, as well as potential cultural influences. We present the process of obtaining normative data for the MCCB in Spain with administration of the battery to a general community standardization sample. In addition, we examine the influence of age, gender, and educational level on test performance. The MCCB was administered to a total sample of 210 healthy volunteers, at three Spanish sites. For each site, recruitment of the sample was stratified according to age, gender, and educational level. Our findings indicate significant age, gender, and education effects on the normative data for the MCCB in Spain, which are comparable to those effects described for the original standardized English version in the U.S. The fact that the normative data are comparable, and that the variables age, gender, and education have a similar influence on performance, supports the robustness of the MCCB for use in different countries.

Therapeutic effects of cerebrolysin added to risperidone in patients with schizophrenia dominated by negative symptoms

OBJECTIVE

Cerebrolysin is a nootropic drug with unique neurotrophic activities directly affecting cerebral neurons. This study evaluated the efficacy and safety of cerebrolysin added to risperidone in patients with schizophrenia dominated by negative symptoms.

METHODS

The trial was a double-blind, placebo-controlled, parallel-group design. A total of 109 patients who met the DSM-IV diagnostic criteria for schizophrenia were randomly assigned to cerebrolysin (cerebrolysin plus risperidone, n=55) or placebo (risperidone only, n=54) groups. Intravenous infusions of 30 ml cerebrolysin or placebo were given once daily from Monday to Friday for 4 weeks. Efficacy was assessed with measurements including the Positive and Negative Symptoms Scale (PANSS), Wechsler Memory Scale (WMS), modified Chinese Wechsler Adult Intelligence Scale (mWAIS). and Clinical Global Impression (CGI).

RESULTS

Patients in both groups demonstrated improvements in psychiatric symptoms and cognitive and memory performance as assessed by PANSS, mWAIS, and WMS over the trial. There was no difference in rates of change in the PANSS total score or negative score between the two treatment groups. Patients treated with cerebrolysin showed significantly greater improvements in cognitive and memory function from week 2. No severe treatment adverse events were observed in either group. The frequency of adverse events was comparable between the two groups at the end of the treatment.

CONCLUSION

Cerebrolysin added to risperidone did not augment the efficacy of risperidone in treating the psychotic symptoms of schizophrenia patients over an 8-week trial. Cerebrolysin at 30 ml per day as an adjunctive treatment was safe and may improve cognitive and memory functions of patients with schizophrenia dominated by negative symptoms.

Schizophrenia as a disorder of too little dopamine: implications for symptoms and treatment

Antipsychotics represent the first effective therapy for schizophrenia, with their benefits linked to dopamine D2 blockade. Schizophrenia was soon identified as a hyperdopaminergic disorder, and antipsychotics proved to be reasonably effective in controlling positive symptoms. However, over the years, schizophrenia has been reconceptualized more broadly, now defined as a heterogeneous disorder with multiple symptom domains. Negative and cognitive features, not particularly responsive to antipsychotic therapy, have taken on increased importance--current thinking suggests that these domains predate the onset of positive symptoms and are more closely tied to functional outcome. That they are better understood in the context of decreased dopamine activity suggests that schizophrenia may fundamentally represent a hypodopaminergic disorder. This shift in thinking has important theoretical implications from the standpoint of etiology and pathophysiology, but also clinically in terms of treatment and drug development.

More evidence on proneurocognitive effects of add-on mirtazapine in schizophrenia

Enhancement of neurocognition is essential in the treatment of schizophrenia. In our previously reported six-week randomized controlled trial (RCT) mirtazapine added to conventional antipsychotics improved not only negative, but also positive symptoms and neurocognition in difficult-to-treat schizophrenia. The present study aimed to explore whether a prolonged exposure to mirtazapine could further improve neurocognition. Completers of the RCT who were able and willing to proceed to the extension phase received open label mirtazapine for an additional 6 weeks. During the extension phase, both groups (i.e., patients who previously received mirtazapine and those who received placebo) and the whole population showed improvement on a number of neurocognitive tests. Patients who shifted to open label mirtazapine from placebo achieved in the six following weeks similar results as their initially mirtazapine-treated counterparts did during their first 6 weeks of mirtazapine exposure. Middle-term mirtazapine treatment (12 weeks) demonstrated an advantage over short-term mirtazapine treatment (6 weeks) on Stroop Dots time and Trail Making Test, part B, number of mistakes (t = -2.562, p = 0.035 and t = -2.42, p = 0.043, correspondingly). Mirtazapine added to antipsychotics consistently shows desirable effects on neurocognition. Lengthy treatment seems worthwhile. Mirtazapine may become a safe and cost-saving neurocognitive enhancer in schizophrenia, yet more studies are needed.

Cognitive performance of long-term institutionalized elderly patients with schizophrenia: A case control study

Cognitive impairment is inherent to the ageing process. Several studies suggest that patients with late-life schizophrenia have more marked cognitive impairment.

Objective

The aim of this study was to compare the cognitive performance of elderly institutionalized patients with schizophrenia and institutionalized elderly control patients without neurological or psychiatric diseases, matched for age, educational level and institutionalization time.

Methods

The Cambridge Examination for Mental Disorders of the Elderly (CAMCOG) was used to test 10 institutionalized elderly patients with schizophrenia. Results were compared with those of 10 institutionalized control patients with history of Hansen's disease.

Results

Patients with schizophrenia showed a worse performance in terms of total CAMCOG score and on its subtests of orientation, language, abstraction, and memory (p≤0.05). Patients with schizophrenia also disclosed a non-significant trend toward lower scores on the MMSE and on calculus.

Conclusion

Findings demonstrated that schizophrenia was associated to worse cognitive impairment in long-term institutionalized elderly patients compared with institutionalized patients without neurological or psychiatric diseases.

Evidence-based guidelines for the pharmacological treatment of schizophrenia: recommendations from the British Association for Psychopharmacology

These guidelines from the British Association for Psychopharmacology address the scope and targets of pharmacological treatment for schizophrenia. A consensus meeting, involving experts in schizophrenia and its treatment, reviewed key areas and considered the strength of evidence and clinical implications. The guidelines were drawn up after extensive feedback from the participants and interested parties, and cover the pharmacological management and treatment of schizophrenia across the various stages of the illness, including first-episode, relapse prevention, and illness that has proved refractory to standard treatment. The practice recommendations presented are based on the available evidence to date, and seek to clarify which interventions are of proven benefit. It is hoped that the recommendations will help to inform clinical decision making for practitioners, and perhaps also serve as a source of information for patients and carers. They are accompanied by a more detailed qualitative review of the available evidence. The strength of supporting evidence for each recommendation is rated.

A cognitive regulatory control model of schizophrenia

A puzzling aspect of schizophrenia concerns the relationship between negative and positive symptoms. Perspectives suggesting that they arise from the same pathophysiological process are not consistent with the numerous differences such as treatment response, and the underlying neurochemistry relevant to treatment. Explanations viewing negative and positive symptoms as independent processes or diseases cannot readily account for the typical developmental course of schizophrenia, consisting of a lengthy prodromal phase of negative followed by positive symptoms. A model of schizophrenia is presented positing that negative and positive symptoms are distinct but interrelated processes, with the former bringing forth the latter due to damaged or impaired cognitive regulatory control processes. The extensive cognitive distortions, thought form variants, and sensory perceptual experiences comprising psychosis represent a natural propensity derived from the evolution of human intelligence. To facilitate reality congruency typically necessary for adaptive functioning, cognitive regulatory control processes normally prevent these extreme variants from entering the conscious and awake state. During sleep when there is no need for reality congruency the cognitive regulatory control processes are deactivated and psychotic equivalents are expressed. Psychological defensive functioning can also deactivate these processes and allow psychosis to manifest. The negative symptoms of schizophrenia are seen as arising from diverse neural deficits that impair to varying degrees the cognitive regulatory control processes, thus producing psychosis. The pattern of neural damage determines the negative symptom profile, and the impact on cognitive regulatory control processes influences whether negative or positive symptoms dominate or exist in relatively equal proportions.

Effects of add-on mirtazapine on neurocognition in schizophrenia: a double-blind, randomized, placebo-controlled study

Mirtazapine added to antipsychotics appears to improve the clinical picture of schizophrenia, including both negative and positive symptoms. This study explored the effect of adjunctive mirtazapine on neurocognition in patients with schizophrenia who had shown an insufficient response to first-generation antipsychotics (FGAs). Thirty-seven schizophrenia patients, who were at least moderately ill despite their FGA treatment, received add-on mirtazapine (n=19) or placebo (n=18) in a 6-wk double-blind, randomized trial. Widely used neuropsychological tests were performed to explore visual-spatial functions, verbal and visual memory, executive functions, verbal fluency and general mental and psychomotor speed. The data were analysed on the modified intent-to-treat basis with last observation carried forward. False discovery rate was applied to correct for multiple testing. Mirtazapine outperformed placebo in the domains of visual-spatial ability and general mental speed/attentional control as assessed by, correspondingly, Block Design and Stroop dots. The difference in the degree of change (i.e. change while on mirtazapine minus that on placebo) was 18.6% (p=0.044) and 11.1% (p=0.044), respectively. Adjunctive mirtazapine might offer a safe, effective and cost-saving option as a neurocognitive enhancer for FGA-treated schizophrenia patients. Mirtazapine+FGA combinations may become especially useful in light of the currently increasing attention towards FGAs. Larger and longer studies that incorporate functional outcomes, as well as comparisons with second-generation antipsychotics are, however, still needed for more definite conclusions.

Neurological disorders in schizophrenia

Schizophrenia (SZ) is a complex, heterogeneous, and disabling psychiatric disorder that impairs multiple aspects of human cognitive, perceptual, emotional, and behavioral functioning. SZ is relatively frequent (prevalence around 1%), with onset usually during adolescence or early adulthood, and has a deteriorating course. The rapidly growing area of neuroimaging research has has found clear evidence of many cortical and subcortical abnormalities in individuals with SZ. In this article the most recent findings from multiple studies on neurological disorders in SZ are reviewed, and the authors make a strong argument for a neurological basis of the schizophrenic process.

Preclinical behavioral models for predicting antipsychotic activity

Schizophrenia is a major psychiatric disease that is characterized by three distinct symptom domains: positive symptoms, negative symptoms, and cognitive impairment. Additionally, treatment with classical antipsychotic medication can be accompanied by important side effects that involve extrapyramidal symptoms (EPS). The discovery of clozapine in the 1970s, which is efficacious in all three symptom domains and has a reduced propensity to induce EPS, has driven research for new antipsychotic agents with a wider spectrum of activity and a lower propensity to induce EPS. The following chapter reviews existing behavioral procedures in animals for their ability to predict compound efficacy against schizophrenia symptoms and liability to induce EPS. Rodent models of positive symptoms include procedures related to hyperfunction in central dopamine and serotonin (5-hydroxytryptamine) systems and hypofunction of central glutamatergic (N-methyl-d-aspartate) neurotransmission. Procedures for evaluating negative symptoms include rodent models of anhedonia, affective flattening, and diminished social interaction. Cognitive deficits can be assessed in rodent models of attention (prepulse inhibition (PPI), latent inhibition) and of learning and memory (passive avoidance, object and social recognition, Morris water maze, and operant-delayed alternation). The relevance of the conditioned avoidance response (CAR) is also discussed. A final section reviews animal procedures for assessing EPS liability, in particular parkinsonism (catalepsy), acute dystonia (purposeless chewing in rodents, dystonia in monkeys), akathisia (defecation in rodents), and tardive dyskinesia (long-term antipsychotic treatment in rodents and monkeys).

Smoking, nicotine and neuropsychiatric disorders

Tobacco smoking is an extremely addictive and harmful form of nicotine (NIC) consumption, but unfortunately also the most prevalent. Although disproportionately high frequencies of smoking and its health consequences among psychiatric patients are widely known, the neurobiological background of this epidemiological association is still obscure. The diverse neuroactive effects of NIC and some other major tobacco smoke constituents in the central nervous system may underlie this association. This present paper summarizes the pharmacology of NIC and its receptors (nAChR) based on a systematic review of the literature. The role of the brain's reward system(s) in NIC addiction and the results of functional and structural neuroimaging studies on smoking-related states and behaviors (i.e. dependence, craving, withdrawal) are also discussed. In addition, the epidemiological, neurobiological, and genetic aspects of smoking in several specific neuropsychiatric disorders are reviewed and the clinical relevance of smoking in these disease states addressed.

A reversible model of the cognitive impairment associated with schizophrenia in monkeys: potential therapeutic effects of two nicotinic acetylcholine receptor agonists

In monkeys proficient in the performance of a computer-assisted delayed response task, administration of sub-sedative doses of ketamine significantly impaired task performance after the 2mg/kg dose, producing a decrease in accuracies across all four delay intervals. Ketamine elicited occasional and inconsistent increases in task latencies. But in general processing speed was not dramatically affected by the test dose. Pretreatment with the alpha7 nicotinic receptor agonist GTS-21 (DMXB-A) [3-[(3E)-3-[(2,4-dimethoxyphenyl) methylidene]-5,6-dihydro-4H-pyridin-2-yl]pyridine] produced a dose-dependent attenuation of ketamine-induced decreases in task accuracies. In fact, the best dose of GTS-21 completely reversed the effects of ketamine. The nicotine metabolite cotinine is a cognitive-enhancer, and active in models predictive of antipsychotic activity. Pretreatment with cotinine did not reverse the task deficits produced by ketamine, and selection of a best dose was necessary to show the activity of cotinine. However, the best dose of cotinine, like GTS-21, completely reversed the ketamine-induced task deficits. Task accuracies were increased relative to their non-ketamine baselines during sessions run 24h later. The cotinine-ketamine order of administration was reversed to provide a more clinically relevant model, and cotinine post-treatment regimen produced a clear reversal of the ketamine-induced task deficits. The protracted task improvement also was still evident. The DMTS task impairment induced by ketamine was capable of being completely reversed by two compounds that are known to improve working memory and cognition. The model could provide a means of late stage preclinical evaluation of new compounds that address the cognitive impairment associated with major psychotic disease.