Brian Kirkpatrick

Meta-Analysis of Cytokine Alterations in Schizophrenia: Clinical Status and Antipsychotic Effects

BACKGROUNDnSchizophrenia is associated with immune system dysfunction, including aberrant cytokine levels. We performed a meta-analysis of these associations, considering effects of clinical status and antipsychotic treatment following an acute illness exacerbation.nnnMETHODSnWe identified articles by searching PubMed, PsychInfo, and Institute for Scientific Information and the reference lists of identified studies.nnnRESULTSnForty studies met the inclusion criteria. Effect sizes were similar for studies of acutely relapsed inpatients (AR) and first-episode psychosis (FEP). Interleukin (IL)-1β, IL-6, and transforming growth factor-β (TGF-β) appeared to be state markers, as they were increased in AR and FEP (p < .001 for each) and normalized with antipsychotic treatment (p < .001, p = .008, and p = .005, respectively). In contrast, IL-12, interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and soluble IL-2 receptor (sIL-2R) appeared to be trait markers, as levels remained elevated in acute exacerbations and following antipsychotic treatment. There was no difference in IL-6 levels between stable medicated outpatients and control subjects (p = .69). In the cerebrospinal fluid, IL-1β was significantly decreased in schizophrenia versus controls (p = .01).nnnCONCLUSIONSnSimilar effect sizes in AR and FEP suggest that the association between cytokine abnormalities and acute exacerbations of schizophrenia is independent of antipsychotic medications. While some cytokines (IL-1β, IL-6, and TGF-β) may be state markers for acute exacerbations, others (IL-12, IFN-γ, TNF-α, and sIL-2R) may be trait markers. Although these results could provide the basis for future hypothesis testing, most studies did not control for potential confounding factors such as body mass index and smoking.

The Brief Negative Symptom Scale: Psychometric Properties

The participants in the NIMH-MATRICS Consensus Development Conference on Negative Symptoms recommended that an instrument be developed that measured blunted affect, alogia, asociality, anhedonia, and avolition. The Brief Negative Symptom Scale (BNSS) is a 13-item instrument designed for clinical trials and other studies that measures these 5 domains. The interrater, test-retest, and internal consistency of the instrument were strong, with respective intraclass correlation coefficients of 0.93 for the BNSS total score and values of 0.89-0.95 for individual subscales. Comparisons with positive symptoms and other negative symptom instruments supported the discriminant and concurrent validity of the instrument.

Metabolic profile of antipsychotic-naive individuals with non-affective psychosis

BACKGROUNDnSome studies suggest individuals with schizophrenia have an increased risk of diabetes prior to antipsychotic use. Small sample sizes and the potential for confounding by hypercortisolaemia have decreased confidence in those results.nnnAIMSnTo examine diabetes-related factors in newly diagnosed, antipsychotic-naive people with non-affective psychosis.nnnMETHODnParticipants with psychosis (the psychosis group; n = 50) and matched controls (the control group; n = 50) were given a 2 h oral glucose tolerance test. Fasting concentrations were also determined for adiponectin, interleukin-6 and C-reactive protein.nnnRESULTSnCompared with the control group, the psychosis group had significant increases in 2 h glucose and interleukin-6 concentrations, and in the prevalence of abnormal glucose tolerance (16% of psychosis group v. 0% of control group). Adiponectin and C-reactive protein concentrations did not differ significantly between the two groups. These findings could not be attributed to differences in cortisol concentrations, smoking, gender, neighbourhood of residence, body mass index, aerobic conditioning, ethnicity, socioeconomic status or age.nnnCONCLUSIONSnIndividuals with non-affective psychosis appear to have an increased prevalence of abnormal glucose tolerance prior to antipsychotic treatment, as well as abnormalities in a related inflammatory molecule. These underlying problems may contribute to the metabolic side-effects of antipsychotic medications.

Deconstructing negative symptoms of schizophrenia: Avolition–apathy and diminished expression clusters predict clinical presentation and functional outcome

BACKGROUNDnPrevious studies indicate that negative symptoms reflect a separable domain of pathology from other symptoms of schizophrenia. However, it is currently unclear whether negative symptoms themselves are multi-faceted, and whether sub-groups of patients who display unique negative symptom profiles can be identified.nnnMETHODSnA data-driven approach was used to examine the heterogeneity of negative symptom presentations in two samples: Study 1 included 199 individuals with schizophrenia assessed with a standard measure of negative symptoms and Study 2 included 169 individuals meeting criteria for deficit schizophrenia (i.e., primary and enduring negative symptoms) assessed with a specialized measure of deficit symptoms. Cluster analysis was used to determine whether different groups of patients with distinct negative symptoms profiles could be identified.nnnRESULTSnAcross both studies, we found evidence for two distinctive negative symptom sub-groups: one group with predominantly Avolition-Apathy (AA) symptoms and another with a predominantly Diminished Expression (DE) profile. Follow-up discriminant function analyses confirmed the validity of these groups. AA and DE negative symptom sub-groups significantly differed on clinically relevant external validators, including measures of functional outcome, premorbid adjustment, clinical course, disorganized symptoms, social cognition, sex, and ethnicity.nnnCONCLUSIONSnThese results suggest that distinct subgroups of patients with elevated AA or DE can be identified within the broader diagnosis of schizophrenia and that these subgroups show clinically meaningful differences in presentation. Additionally, AA tends to be associated with poorer outcomes than DE, suggesting that it may be a more severe aspect of psychopathology.

Inflammation and Schizophrenia

An association between inflammatory abnormalities and schizophrenia has been found repeatedly. The purposes of this special feature are to clarify the key findings on inflammation in schizophrenia, identify major gaps in the literature, and suggest priorities for research in this area.

Meta-analysis of Paternal Age and Schizophrenia Risk in Male Versus Female Offspring

INTRODUCTIONnAdvanced paternal age (APA) is a reported risk factor for schizophrenia in the offspring. We performed a meta-analysis of this association, considering the effect of gender and study design.nnnMETHODSnWe identified articles by searching Pub Med, PsychInfo, ISI, and EMBASE, and the reference lists of identified studies. Previously unpublished data from the Northern Finland 1966 Birth Cohort (NFBC 1966) study were also included.nnnRESULTSnThere were 6 cohort studies and 6 case-control studies that met the inclusion criteria. In both study designs, there was a significant increase in risk of schizophrenia in the offspring of older fathers (≥30) compared to a reference paternal age of 25-29, with no gender differences. The relative risk (RR) in the oldest fathers (≥50) was 1.66 [95% confidence interval (95% CI): 1.46-1.89, P < 0.01]. A significant increase in risk was also found for younger fathers (<25) in males (RR = 1.08, 95% CI: 1.02-1.14, P = 0.01) but not females (RR = 1.04, 95% CI: 0.97-1.14, P = 0.28). The population attributable risk percentage (PAR%) was 10% for paternal age ≥30 and 5% for paternal age <25.nnnDISCUSSIONnBoth APA (≥30) and younger paternal age (<25) increase the risk of schizophrenia; younger paternal age may be associated with an increased risk in males but not females. This risk factor increases the risk of schizophrenia as much as any single candidate gene of risk. The mechanism of these associations is not known and may differ for older and younger fathers.

Deficit schizophrenia: an update

The criteria for deficit schizophrenia were designed to define a group of patients with enduring, primary (or idiopathic) negative symptoms. In 2001, a review of the literature suggested that deficit schizophrenia constitutes a disease separate from nondeficit forms of schizophrenia. Here we provide a review of new studies, not included in that paper, in which patients with deficit schizophrenia and those with nondeficit schizophrenia were compared on dimensions typically used to distinguish diseases: signs and symptoms, course of illness, pathophysiological correlates, risk and etiological factors, and treatment response. Replicated findings and new evidence of double dissociation supporting the separate disease hypothesis are highlighted. Weaknesses in research and treatment options for these patients are also emphasized.

A Multicenter, Randomized, Double-Blind, Placebo-Controlled, 16-Week Study of Adjunctive Aripiprazole for Schizophrenia or Schizoaffective Disorder Inadequately Treated With Quetiapine or Risperidone Monotherapy

OBJECTIVEnCombining antipsychotics is common practice in the treatment of schizophrenia. This study investigated aripiprazole adjunctive to risperidone or quetiapine for treating schizophrenia and schizoaffective disorder.nnnMETHODnIn this multicenter, double-blind, 16-week, placebo-controlled study conducted at 43 American sites from July 2006 to October 2007, patients with chronic, stable schizophrenia or schizoaffective disorder diagnosed with DSM-IV-TR were randomly assigned to receive aripiprazole (2-15 mg/d) or placebo in addition to a stable regimen of quetiapine (400-800 mg/d) or risperidone (4-8 mg/d). The primary outcome measure was the mean change from baseline to endpoint (week 16, last observation carried forward) in the Positive and Negative Syndrome Scale (PANSS) total score.nnnRESULTSn323 subjects being treated with either risperidone (n = 177) or quetiapine (n = 146) were randomly assigned to receive adjunctive aripiprazole (n = 168) or placebo (n = 155). Baseline characteristics were similar (mean PANSS total score: aripiprazole, 74.5; placebo, 75.9) except for history of suicide attempts (aripiprazole, 27%; placebo, 40%). Nearly 70% of subjects in each arm completed the trial. Adjunctive aripiprazole and placebo groups were similar in the mean change from baseline to endpoint in the PANSS total score (aripiprazole, -8.8; placebo, -8.9; P = .942). The incidence of treatment-emergent adverse events was similar between groups. Mean changes in Simpson-Angus Scale, Abnormal Involuntary Movement Scale, and Barnes Akathisia Rating Scale scores were not statistically significantly different. Adjunctive aripiprazole was associated with statistically significantly greater decreases in mean serum prolactin levels from baseline than was adjunctive placebo (-12.6 ng/mL for aripiprazole vs -2.2 ng/mL for placebo; P < .001), an effect that was seen in the risperidone subgroup (-18.7 ng/mL vs -1.9 ng/mL; P < .001) but not in the quetiapine subgroup (-3.01 ng/mL vs +0.15 ng/mL; P = .104).nnnCONCLUSIONSnThe addition of aripiprazole to risperidone or quetiapine was not associated with improvement in psychiatric symptoms but was generally safe and well tolerated. Further research is warranted to explore whether antipsychotic combination therapy offers benefits to particular patient populations-for example, in cases of hyperprolactinemia.nnnTRIAL REGISTRATIONnclinicaltrials.gov Identifier: NCT00325689.

Telomere Length and Pulse Pressure in Newly Diagnosed, Antipsychotic-Naive Patients With Nonaffective Psychosis

INTRODUCTIONnRecent studies suggest that in addition to factors such as treatment side effects, suicide, and poor health habits, people with schizophrenia may have an increased risk of diabetes prior to antipsychotic treatment. Diabetes is associated with an increased pulse pressure (PP) and a shortened telomere. We tested the hypothesis that prior to antipsychotic treatment, schizophrenia and related disorders are associated with a shortened telomere, as well as an increased PP.nnnMETHODSnTelomere content (which is highly correlated with telomere length) and PP were measured in newly diagnosed, antipsychotic-naive patients with schizophrenia and related disorders on first clinical contact and in matched control subjects. Both groups were also administered an oral glucose tolerance test.nnnRESULTSnCompared with control subjects, the patients with psychosis had decreased telomere content and an increased PP. As previously reported, they also had increased glucose concentrations at 2 hours. These differences could not be attributed to differences in age, ethnicity, smoking, gender, body mass index, neighborhood of residence, socioeconomic status, aerobic conditioning, or an increased cortisol concentration in the psychotic subjects.nnnDISCUSSIONnThese results suggest that prior to antipsychotic use, nonaffective psychosis is associated with reduced telomere content and increased PP, indices that have been linked to an increased risk of diabetes and hypertension.

Next-generation negative symptom assessment for clinical trials: Validation of the Brief Negative Symptom Scale

The current study examined the psychometric properties of the Brief Negative Symptom Scale (BNSS), a next-generation rating instrument developed in response to the NIMH sponsored consensus development conference on negative symptoms. Participants included 100 individuals with a DSM-IV diagnosis of schizophrenia or schizoaffective disorder who completed a clinical interview designed to assess negative, positive, disorganized, and general psychiatric symptoms, as well as functional outcome. A battery of anhedonia questionnaires and neuropsychological tests were also administered. Results indicated that the BNSS has excellent internal consistency and temporal stability, as well as good convergent and discriminant validity in its relationships with other symptom rating scales, functional outcome, self-reported anhedonia, and neuropsychological test scores. Given its brevity (13-items, 15-minute interview) and good psychometric characteristics, the BNSS can be considered a promising new instrument for use in clinical trials.