Multimodal assessment of white matter microstructure in antipsychotic-naïve schizophrenia patients and confounding effects of recreational drug use.

Cerebral white matter (WM) aberrations in schizophrenia have been linked to multiple neurobiological substrates but the underlying mechanisms remain unknown. Moreover, antipsychotic treatment and substance use constitute potential confounders. Multimodal studies using diffusion tensor imaging (DTI) and magnetization transfer imaging (MTI) may provide deeper insight into the whole brain WM pathophysiology in schizophrenia. We combined DTI and MTI to investigate WM integrity in 51 antipsychotic-naïve, first-episode schizophrenia patients and 55 matched healthy controls, using 3 T magnetic resonance imaging (MRI). Psychopathology was assessed with the positive and negative syndrome scale (PANSS). A whole brain partial least squares correlation (PLSC) method was used to conjointly analyze DTI-derived measures (fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), mode of anisotropy (MO)) and the magnetization transfer ratio (MTR) to identify group differences, and associations with psychopathology. In secondary analyses, we excluded recreational substance users from both groups resulting in 34 patients and 51 healthy controls. The primary PLSC group difference analysis identified a significant pattern of lower FA, AD, MO and higher RD in patients (p = 0.04). This pattern suggests disorganized WM microstructure in patients. The secondary PLSC group difference analysis without recreational substance users revealed a significant pattern of lower FA and higher AD, RD, MO, MTR in patients (p = 0.04). This pattern in the substance free patients is consistent with higher extracellular free-water concentrations, which may reflect neuroinflammation. No significant associations with psychopathology were observed. Recreational substance use appears to be a confounding issue, which calls for attention in future WM studies.

Interview and questionnaire assessment of cognitive impairment in subjects at ultra-high risk for psychosis: Associations with cognitive test performance, psychosocial functioning, and positive symptoms.

Impaired cognitive test performance is well-documented in subjects at ultra-high risk (UHR) for psychosis. However, assessment of cognitive deficits as manifested in real life is a neglected area of UHR research that may add to the understanding of cognitive impairment and its relationship with psychosocial functioning and positive symptomatology. This study applied the interview-based Schizophrenia Cognition Rating Scale (SCoRS) and the questionnaire-based Behavior Rating Inventory of Executive Function - Adult Version (BRIEF-A) in a cross-sectional sample of 39 UHR subjects and 50 healthy controls. Cognitive test performance, psychosocial functioning, and positive symptoms were also assessed. The UHR subjects demonstrated significant cognitive impairment, with large effect sizes for the SCoRS and BRIEF-A composite outcome variables (rs = -0.67 to -0.80) and a neurocognitive composite score (d = -0.97). Within the UHR group, several significant associations between worse cognitive ratings and worse cognitive test performance (rs = -0.210 to -0.343), poorer psychosocial functioning (rs = -0.058 to -0.728), and worse positive symptoms (rs= 0.415 to 0.478) were found. Worse cognitive test performance showed significant associations with more pronounced positive symptoms (rs = -0.299 to -0.457). Interview and questionnaire assessment may hold promise for supplementing traditional performance-based cognitive assessment in identifying treatment targets in the UHR population.

Acute and long-term psychiatric side effects of mefloquine: a follow-up on Danish adverse event reports.

BACKGROUND: The aim of the study was to explore the profile of acute and long-term psychiatric side effects associated with mefloquine. METHODS: Subjects (n = 73) reported to a Danish national register during five consecutive years for mefloquine associated side effects were included. Acute psychiatric side effects were retrospectively assessed using the SCL-90-R and questions based on Present State Examination (PSE). Subjects reporting suspected psychotic states were contacted for a personal PSE interview. Electronic records of psychiatric hospitalizations and diagnoses were cross-checked. Long-term effects were evaluated with SF-36. SCL-90-R and SF-36 data were compared to age- and gender matched controls. RESULTS: In the SCL-90-R, clinically significant scores for anxiety, phobic anxiety and depression were found in 55%, 51%, and 44% of the mefloquine group. Substantial acute phase psychotic symptoms were found in 15% and were time-limited. Illusions/hallucinations were more frequently observed among women. Cases of hypomania/mania in the acute phase were 5.5%. Significant long-term mental health effects were demonstrated for the SF-36 subscales mental health (MH), role emotional (RE), and vitality (VT) in the mefloquine group compared to matched controls. CONCLUSION: The most frequent acute psychiatric problems were anxiety, depression, and psychotic symptoms. Data indicated that subjects experiencing acute mefloquine adverse side effects may develop long-term mental health problems with a decreased sense of global quality of life with lack of energy, nervousness, and depression.

Concurrent functional magnetic resonance imaging and electroencephalography assessment of sensory gating in schizophrenia.

Schizophrenia is frequently accompanied by deficits in basic information processing, such as sensory gating. The sources behind deficient sensory gating in schizophrenia patients are, however, still largely unclear. The aim of the current study was to identify the brain structures involved in deficient sensory gating in schizophrenia patients. Twenty healthy male volunteers and 23 male schizophrenia patients were initially assessed in a somatosensory P50 suppression paradigm using concurrent electroencephalography (EEG)/functional magnetic resonance imaging (fMRI) methodology. The trials consisted of single stimuli or pairs of identical stimuli with either 500 ms or 1,000 ms interstimulus intervals. Not all subjects showed a P50 waveform as a result of the somatosensory stimuli: It was detected in 13 schizophrenia patients and 15 control subjects. Significant P50 suppression was found in the 500 ms trials in controls only. Region of interest analyses were performed for a priori chosen regions. Significant negative correlations between P50 ratios and the BOLD response were found bilaterally in the hippocampus, thalamus, anterior and posterior superior temporal gyrus (STG), and in the left inferior frontal gyrus pars opercularis. However, significant group differences were found in the hippocampus and the thalamus only. This is the first study in which P50 suppression was assessed in schizophrenia patients with concurrent fMRI/EEG methodology. The data support that the STG, thalamus, inferior frontal gyrus, and the hippocampus are involved in P50 suppression. However, of these structures only the hippocampus and thalamus appeared involved in the altered sensory processing found in schizophrenia.

Association of antipsychotic polypharmacy with health service cost: a register-based cost analysis.

OBJECTIVE: To investigate the association of antipsychotic polypharmacy in schizophrenia with cost of primary and secondary health service use. METHOD: Comparative analysis of health service cost for patients prescribed antipsychotic polypharmacy versus antipsychotic monotherapy. Resource utilisation and costs were described using central Danish registers for a 2 year period (2007-2008). We included patients attached to one of two Danish psychiatric referral centres in 1 January 2008 and/or 1 January 2009. Their prescribed treatment with either antipsychotic polypharmacy or monotherapy at the two cross-sectional dates was recorded and used as proxy of polypharmacy exposure during the preceding year. A multivariate generalised linear model was fitted with total costs of primary and secondary health service use as dependent variable, and antipsychotic polypharmacy, diagnosis, age, gender, disease duration, psychiatric inpatient admissions, and treatment site as covariates. RESULTS: The sample consisted of 736 outpatients with a diagnosis in the schizophrenia spectrum. Antipsychotic polypharmacy was associated with significantly higher total health service costs compared with monotherapy (2007: 25% higher costs; 2008: 17% higher costs) when adjusting for potential confounders and risk factors. A subgroup analysis suggested that the excessive costs associated with antipsychotic polypharmacy were partly accounted for by the functional level of the patients. CONCLUSION: The results demonstrate that antipsychotic co-prescribing is associated with increased use of health care services, even though no causal relations can be inferred from an observational study.

Assessment of auditory sensory processing in a neurodevelopmental animal model of schizophrenia--gating of auditory-evoked potentials and prepulse inhibition.

The use of translational approaches to validate animal models is needed for the development of treatments that can effectively alleviate cognitive impairments associated with schizophrenia, which are unsuccessfully treated by the current available therapies. Deficits in pre-attentive stages of sensory information processing seen in schizophrenia patients, can be assessed by highly homologues methods in both humans and rodents, evident by the prepulse inhibition (PPI) of the auditory startle response and the P50 (termed P1 here) suppression paradigms. Treatment with the NMDA receptor antagonist PCP on postnatal days 7, 9, and 11 reliably induce cognitive impairments resembling those presented by schizophrenia patients. Here we evaluate the potential of early postnatal PCP (20mg/kg) treatment in Lister Hooded rats to induce post-pubertal deficits in PPI and changes, such as reduced gating, in the P1 suppression paradigm in the EEG. The results indicate that early postnatal PCP treatment to rats leads to a reduction in PPI of the acoustic startle response. Furthermore, treated animals were assessed in the P1 suppression paradigm and produced significant changes in auditory-evoked potentials (AEP), specifically by an increased P1 amplitude and reduced P2 (P200 in humans) gating. However, the treatment neither disrupted normal P1 gating nor reduced N1 (N100 in humans) amplitude, representing two phenomena that are usually found to be disturbed in schizophrenia. In conclusion, the current findings confirm measures of early information processing to show high resemblance between rodents and humans, and indicate that early postnatal PCP-treated rats show deficits in pre-attentional processing, which are distinct from those observed in schizophrenia patients.