Structural neural networks subserving oculomotor function in first-episode schizophrenia

BACKGROUND: Smooth pursuit and antisaccade abnormalities are well documented in schizophrenia, but their neuropathological correlates remain unclear. METHODS: In this study, we used statistical parametric mapping to investigate the relationship between oculomotor abnormalities and brain structure in a sample of first-episode schizophrenia patients (n = 27). In addition to conventional volumetric magnetic resonance imaging, we also used magnetization transfer ratio, a technique that allows more precise tissue characterization. RESULTS: We found that smooth pursuit abnormalities were associated with reduced magnetization transfer ratio in several regions, predominantly in the right prefrontal cortex. Antisaccade errors correlated with gray matter volume in the right medial superior frontal cortex as measured by conventional magnetic resonance imaging but not with magnetization transfer ratio. CONCLUSIONS: These preliminary results demonstrate that specific structural abnormalities are associated with abnormal eye movements in schizophrenia

The Relationship Between IQ, Memory, Executive Function, and Processing Speed in Recent-Onset Psychosis: 1-Year Stability and Clinical Outcome

Studies commonly report poor performance in psychotic patients compared with controls on tasks testing a range of cognitive functions, but, because current IQ is often not matched between these groups, it is difficult to determine whether this represents a generalized deficit or specific abnormalities. Fifty-three first-episode psychosis patients and 53 healthy controls, one-to-one matched for sex, age, and full-scale current IQ, were compared on Wechsler Adult Intelligence Scale (WAIS) subtests representing indices of perceptual organization, verbal comprehension, processing speed, and working memory as well as other tests of executive function and episodic memory. The groups showed an equivalent pattern of performance on all WAIS subtests except digit symbol processing speed, on which the patients were significantly worse. Patients were also worse on measures where performance correlated with digit symbol score, namely working and verbal memory tasks. Standardized residual scores for each subtest were calculated for each patient using the difference between their actual subtest score and a predicted subtest score based on their full-scale IQ and the performance of controls. Scaled scores and residual scores were examined for relationships with clinical measures. Digit symbol–scaled score was significantly correlated with concurrent negative syndrome score at baseline, and digit symbol residual score significantly predicted residual negative symptoms at 1-year follow-up. In summary, our comparison of patients and controls precisely matched for IQ revealed that processing speed was attenuated in recent-onset schizophrenia, contributed significantly to working and episodic memory deficits, and was a prognostic factor for poor outcome at 1 year

Comorbid substance use and age at onset of schizophrenia.

BACKGROUND: Substance use may be a risk factor for the onset of schizophrenia. AIMS: To examine the association between substance use and age at onset in substance use and age at onset in a UK, inner-city sample of people with recent-onset schizophrenia. METHOD: The study sample consisted of 152 people recruited to the West London First-Episode Schizophrenia Study. Self-reported data on drug and alcohol use, as well as information on age at onset of psychosis, were collected. Mental state, cognition (IQ, memory and executive function) and social function were also assessed. RESULTS: In total, 60% of the participants were smokers, 27% reported a history of problems with alcohol use, 35% reported current substance use (not including alcohol), and 68% reported lifetime substance use (cannabis and psychostimulants were most commonly used). Cannabis use and gender had independent effects on age at onset of psychosis, after adjusting for alcohol misuse and use of other drugs. CONCLUSIONS: The strong association between self-reported cannabis use and earlier onset of psychosis provides further evidence that schizophrenia may be precipitated by cannabis use and/or that the early onset of symptoms is a risk factor for cannabis use

Gray and white matter brain abnormalities in first-episode schizophrenia inferred from magnetization transfer imaging

Background: Neuroimaging studies suggest that schizophrenia is associated with gray and possibly white matter changes. It is unclear whether these changes are present at illness onset or which brain structures are selectively affected. New imaging methods such as magnetization transfer imaging may be more sensitive than conventional volumetric imaging to the subtle structural brain changes in schizophrenia.Methods: High-resolution volumetric T1-weighted images and magnetization transfer images were acquired from 30 patients (29 with first-episode schizophrenia and 1 with schizophreniform psychoses) and 30 control subjects. Images were processed using voxel-based morphometry, which allows whole-brain analysis.Results: Compared with controls, the magnetization transfer ratio (an index of signal loss derived from magnetization transfer imaging) was reduced bilaterally in the medial prefrontal cortex (right greater than left) 1 insula (left greater than right), and white matter incorporating the fasciculus uncinatus (left greater than right) in the patient group. Analysis of the T1-weighted images did not reveal significant volumetric differences between patients and controls.Conclusions: Gray and white matter abnormalities are present in schizophrenia at illness onset. The magnetization transfer ratio is sensitive to these abnormalities, which cannot be explained by detectable atrophy in our patient group

Clinical correlates of early medication adherence: West London first episode schizophrenia study.

Objective: Little is known about factors that mediate adherence with medication during the early stages of antipsychotic treatment in schizophrenia. This study sought to identify factors that may be associated with medication adherence in first-episode schizophrenia.Method: In 101 patients, adherence was assessed along with potentially relevant variables, including attitudes toward medication, insight, substance misuse, side effects and psychopathology.Results: In a linear regression analysis, negative attitudes toward medication and a relative lack of insight contributed significantly towards poor adherence. Although poorly adherent patients had significantly higher scores on negative and disorganization syndromes, these did not contribute significantly towards adherence. Adverse medication side effects, subjective well-being and substance misuse showed no significant association with adherence.Conclusion: At the initiation of drug treatment, attitudes toward medication and insight appear more relevant to medication adherence than side effects. Adherence appears to reflect a complex interaction of influences, which may change over time

Naturalistic follow-up of co-morbid substance use in schizophrenia: The West London first-episode study

Background. The impact of co-morbid substance use in first-episode schizophrenia has not been fully explored. Method. This naturalistic follow-up of a cohort of 152 people with first-episode schizophrenia examined substance use and clinical outcome in terms of symptoms and social and neuropsychological function. Results. Data were collected on 85 (56%) of the patient cohort after a median period of 14 months. Over the follow-up period, the proportion of smokers rose from 60% at baseline to 64%. While 30% reported lifetime problem drinking of alcohol at baseline, only 15% had problem drinking at follow-up. Furthermore, while at baseline 63% reported lifetime cannabis use and 32% were currently using the drug, by the follow-up assessment the latter figure had fallen to 18.5%. At follow-up, persistent substance users had significantly more severe positive and depressive symptoms and greater overall severity of illness. A report of no lifetime substance use at baseline was associated with greater improvement in spatial working memory (SWM) at follow-up. Conclusions. Past substance use may impede recovery of SWM performance in people with schizophrenia in the year or so following first presentation to psychiatric services. The prevalence of substance use other than tobacco tends to diminish over this period, in the absence of specific interventions. Persistent substance use in first-episode schizophrenia is associated with more severe positive and depressive symptoms but not negative symptoms, and should be a target for specific treatment intervention. © 2007 Cambridge University Press