Clozapine for the treatment-resistant schizophrenic. A double-blind comparison with chlorpromazine

The treatment of schizophrenic patients who fail to respond to adequate trials of neuroleptics is a major challenge. Clozapine, an atypical antipsychotic drug, has long been of scientific interest, but its clinical development has been delayed because of an associated risk of agranulocytosis. This report describes a multicenter clinical trial to assess clozapine's efficacy in the treatment of patients who are refractory to neuroleptics. DSM-III schizophrenics who had failed to respond to at least three different neuroleptics underwent a prospective, single-blind trial of haloperidol (mean dosage, 61 +/- 14 mg/d) for six weeks. Patients whose condition remained unimproved were then randomly assigned, in a double-blind manner, to clozapine (up to 900 mg/d) or chlorpromazine (up to 1800 mg/d) for six weeks. Two hundred sixty-eight patients were entered in the double-blind comparison. When a priori criteria were used, 30% of the clozapine-treated patients were categorized as responders compared with 4% of chlorpromazine-treated patients. Clozapine produced significantly greater improvement on the Brief Psychiatric Rating Scale, Clinical Global Impression Scale, and Nurses' Observation Scale for Inpatient Evaluation; this improvement included "negative" as well as positive symptom areas. Although no cases of agranulocytosis occurred during this relatively brief study, in our view, the apparently increased comparative risk requires that the use of clozapine be limited to selected treatment-resistant patients.

The Strengths and Difficulties Questionnaire: a pilot study on the validity of the self-report version

The self-report version of the Strengths and Difficulties Questionnaire (SDQ) was administered to two samples of 11-16 year olds: 83 young people in the community and 116 young people attending a mental health clinic. The questionnaire discriminated satisfactorily between the two samples. For example, the clinic mean for the total difficulties score was 1.4 standard deviations above the community mean, with clinic cases being over six times more likely to have a score in the abnormal range. The correlations between self-report SDQ scores and teacher- or parent-rated SDQ scores compared favourably with the average cross-informant correlations in previous studies of a range of measures. The self-report SDQ appears promising and warrants further evaluation.

Using the Strengths and Difficulties Questionnaire (SDQ) to screen for child psychiatric disorders in a community sample

BACKGROUND

Child psychiatric disorders are common and treatable, but often go undetected and therefore remain untreated.

AIMS

To assess the Strengths and Difficulties Questionnaire (SDQ) as a potential means for improving the detection of child psychiatric disorders in the community.

METHOD

SDQ predictions and independent psychiatric diagnoses were compared in a community sample of 7984 5- to 15-year-olds from the 1999 British Child Mental Health Survey.

RESULTS

Multi-informant (parents, teachers, older children) SDQs identified individuals with a psychiatric diagnosis with a specificity of 94.6% (95% Cl 94.1-95.1%) and a sensitivity of 63.3% (59.7-66.9%). The questionnaires identified over 70% of individuals with conduct, hyperactivity, depressive and some anxiety disorders, but under 50% of individuals with specific phobias, separation anxiety and eating disorders. Sensitivity was substantially poorer with single-informant rather than multi-informant SDQs.

CONCLUSIONS

Community screening programmes based on multi-informant SDQs could potentially increase the detection of child psychiatric disorders, thereby improving access to effective treatments.

Mental health of children and adolescents in Great Britain

The findings described in this report and summarized here focus on the prevalence of mental disorders among 5-15 year olds and on the associations between the presence of a mental disorder and biographic, sociodemographic, socio-economic, and social functioning characteristics of the child and the family. Causal relationships should not be assumed for any of the results presented in this report.

Mental health of children and adolescents in Great Britain

The findings described in this report and summarized here focus on the prevalence of mental disorders among 5-15 year olds and on the associations between the presence of a mental disorder and biographic, sociodemographic, socio-economic, and social functioning characteristics of the child and the family. Causal relationships should not be assumed for any of the results presented in this report.

Fatty acid composition in major depression: decreased omega 3 fractions in cholesteryl esters and increased C20: 4 omega 6/C20:5 omega 3 ratio in cholesteryl esters and phospholipids

Recently, there were some reports that major depression may be accompanied by alterations in serum total cholesterol, cholesterol ester and omega 3 essential fatty acid levels and by an increased C20: 4 omega 6/C20: 5 omega 3, i.e., arachidonic acid/eicosapentaenoic, ratio. The present study aimed to examine fatty acid composition of serum cholesteryl esters and phospholipids in 36 major depressed, 14 minor depressed and 24 normal subjects. Individual saturated (e.g., C14:0; C16:0, C18:0) and unsaturated (e.g., C18:1, C18:2, C20:4) fatty acids in phospholipid and cholesteryl ester fractions were assayed and the sums of the percentages of omega 6 and omega 3, saturated, branched chain and odd chain fatty acids, monoenes as well as the ratios omega 6/omega 3 and C20:4 omega 6/C20:5 omega 3 were calculated. Major depressed subjects had significantly higher C20:4 omega 6/C20:5 omega 3 ratio in both serum cholesteryl esters and phospholipids and a significantly increased omega 6/omega 3 ratio in cholesteryl ester fraction than healthy volunteers and minor depressed subjects. Major depressed subjects had significantly lower C18:3 omega 3 in cholesteryl esters than normal controls. Major depressed subjects showed significantly lower total omega 3 polyunsaturated fatty acids in cholesteryl esters and significantly lower C20:5 omega 3 in serum cholesteryl esters and phospholipids than minor depressed subjects and healthy controls. These findings suggest an abnormal intake or metabolism of essential fatty acids in conjunction with decreased formation of cholesteryl esters in major depression.

Identification of vascular structures as a major source of signal contrast in high resolution 2D and 3D functional activation imaging of the motor cortex at 1.5T: preliminary results

We have measured the T2* signal response associated with cortical activation due to finger motion at 1.5 Tesla. Both thin slice 2D and 3D images show signal intensity changes which vary from 2% to 32% depending on volunteer, echo time, slice thickness, and in-plane resolution. The largest signal change occurred for the thinnest slices and highest resolution (2 mm3). This is consistent with reducing partial volume effects and a simple difference in phase between the intravascular signal and surrounding parenchyma. No inflow enhancement was seen on the 2D or 3D scans, confirming the nature of the signal difference for this approach was due to local field inhomogeneity effects. Using 3D imaging, multiple effects can be seen simultaneously. With a 3D MRA method, it was possible to locate the vessel that was the source of the T2* behavior; it was in each case a vein on the surface of the cortical parenchyma.

The National Psychiatric Morbidity surveys of Great Britain--initial findings from the household survey

BACKGROUND

This paper describes the Household Survey from the National Survey of Psychiatric Morbidity. This covered a sample drawn at random from the population of Britain, with the exception of the Highlands and Islands of Scotland.

METHODS

The Postcode Address file was used as the sampling frame. Nearly 13000 adults aged 16-65 were selected for interview, of whom 10108 (79.4%) were successfully interviewed. Eight per cent could not be contacted and 13% refused interview. Psychiatric assessment was carried out by lay interviewers using the CIS-R. Subjects were also screened for psychosis, and screen-positive individuals were examined by psychiatrists using SCAN.

RESULTS

Sixteen per cent of subjects scored above the standard cut-off of 12 on the CIS-R. The overall 1-week prevalence of neurotic disorder was 12.3% in males and 19.5% in females. Unmarried and post-marital groups had high rates of disorder, as did single parents and people living on their own. Respondents in Social Class I had notably lower rates of neurotic disorder than the remainder of the sample. Unemployment was strongly associated with disorder. Subjects living in urban areas had a higher overall prevalence, but there was no significant variation by region. Black respondents had higher rates of disorders that were entirely explained by their age, family type and social class. Individual neurotic disorders were all significantly commoner in women, with the exception of panic disorder. The 1-year prevalence of functional psychoses was 4 per 1000, with no sex difference. Alcohol and drug dependence was considerably more prevalent in men.

CONCLUSIONS

For the first time, the survey provides data on the prevalence and correlates of psychiatric disorder on a nationwide sample that can be used to inform equitable and effective national psychiatric services.

Using the Strengths and Difficulties Questionnaire (SDQ) to screen for child psychiatric disorders in a community sample

Child psychiatric disorders are common and treatable, but often go undetected and therefore remain untreated. To assess the Strengths and Difficulties Questionnaire (SDQ) as a potential means for improving the detection of child psychiatric disorders in the community, SDQ predictions and independent psychiatric diagnoses were compared in a community sample of 7984 5-15 year olds from the 1999 British Child Mental Health Survey. Multi-informant (parents, teachers, older children) SDQs identified individuals with a psychiatric diagnosis with a specificity of 94.6% (95% Cl, 94.1-95.1%) and a sensitivity of 63.3% (59.7-66.9%). The questionnaires identified over 70% of individuals with conduct, hyperactivity, depressive, and some anxiety disorders, but fewer than 50% of individuals with specific phobias, separation anxiety and eating disorders. Sensitivity was substantially poorer with single-informant rather than multi-informant SDQs. Community screening programmes based on multi-informant SDQs could potentially increase the detection of child psychiatric disorders, thereby improving access to effective treatments.

The influence of age and sex on the prevalence of depressive conditions: report from the National Survey of Psychiatric Morbidity

BACKGROUND

Women are consistently reported to have a greater prevalence of depressive disorders than men. The reason for this is unclear, and is as likely to be social as biological. There is some evidence that the excess of depression is greater during women's reproductive lives. Data from the National Survey of Psychiatric Morbidity were used to test the hypothesis that the excess disappeared in the post-menopausal years and that obvious social explanations for this were inadequate.

METHOD

Subjects (N = 9792) from a random sample of the British population provided data for the analysis. Psychiatric assessment was carried out by lay interviewers using the CIS-R. Subjects with ICD-10 depressive episode or mixed anxiety/depression were compared with the remainder. Social variables that were likely to contribute to a post-menopausal decline in depressive disorders were controlled in logistic regression analyses.

RESULTS

There was a clear reversal of the sex difference in prevalence of depression in those over age 55. This could not be explained in terms of differential effects of marital status, child care, or employment status.

CONCLUSIONS

This large and representative survey adds considerably to the increasingly held view that the sex difference in prevalence of depression is less apparent in later middle age. This may be linked to the menopause, and our attempts to explain it in terms of obvious conditions among social variables were not successful. More specific studies are required to clarify the finding.

Prevalence of obsessive-compulsive disorder in the British nationwide survey of child mental health

BACKGROUND

Obsessive-compulsive disorder (OCD) is a disorder that appears to be underdiagnosed and undertreated, despite the evidence for effective treatments. There are variable estimates of OCD prevalence in the under-16s and published rates give little indication of age trends.

AIMS

To establish the prevalence and associates of OCD in young people aged 5-15 years.

METHOD

A nationwide (UK) epidemiological study of rates of psychiatric disorder in 5- to 15-year-olds (1999 British Child Mental Health Survey): 10 438 children were assessed.

RESULTS

Twenty-five children with OCD were identified (weighted overall prevalence 0.25%; 95% CI 0.14-0.35), with prevalence rising exponentially with increasing age. Compared with normal controls, children with OCD were more likely to be from lower socio-economic class and of lower intelligence. Only three of these children had been seen by specialist children's services.

CONCLUSIONS

Although OCD is rare in young children, the rate increases towards the adult rates at puberty. Children with OCD have additional psychosocial disadvantage. The majority of the childhood cases identified in this survey appear to have been undetected and untreated.

Concomitants of paranoia in the general population

BACKGROUND

Paranoia is an unregarded but pervasive attribute of human populations. In this study we carried out the most comprehensive investigation so far of the demographic, economic, social and clinical correlates of self-reported paranoia in the general population.

METHOD

Data weighted to be nationally representative were analysed from the Adult Psychiatric Morbidity Survey in England (APMS 2007; n=7281).

RESULTS

The prevalence of paranoid thinking in the previous year ranged from 18.6% reporting that people were against them, to 1.8% reporting potential plots to cause them serious harm. At all levels, paranoia was associated with youth, lower intellectual functioning, being single, poverty, poor physical health, poor social functioning, less perceived social support, stress at work, less social cohesion, less calmness, less happiness, suicidal ideation, a great range of other psychiatric symptoms (including anxiety, worry, phobias, post-traumatic stress and insomnia), cannabis use, problem drinking and increased use of treatment and services.

CONCLUSIONS

Overall, the results indicate that paranoia has the widest of implications for health, emotional well-being, social functioning and social inclusion. Some of these concomitants may contribute to the emergence of paranoid thinking, while others may result from it.

Nicotine, alcohol and drug dependence and psychiatric comorbidity. Results of a national household survey

BACKGROUND

There is a well-recognised relationship between substance use disorders and other psychiatric disorders. This relationship has been well documented in a range of population-based studies.

AIMS

This study aims to report on consumption patterns of and dependence on nicotine, alcohol and non-prescribed drugs and to report on the levels of psychiatric morbidity in these groups.

METHOD

A national household study of psychiatric morbidity was conducted in England and Wales. Psychiatric assessment was based on the Clinical Interview Schedule-Revised (CIS-R). Measures of nicotine, alcohol and drug use and dependence were obtained. This paper compares the levels of psychiatric morbidity in the non-dependent and the nicotine-, alcohol- and drug-dependent cases.

RESULTS

Twelve per cent of the non-dependent population were assessed as having any psychiatric disorder compared with 22% of the nicotine-dependent, 30% of the alcohol-dependent and 45% of the drug-dependent population.

CONCLUSIONS

There is a clear relationship between dependence on nicotine, alcohol and drugs and other psychiatric morbidity.

The Strengths and Difficulties Questionnaire: a pilot study on the validity of the self-report version

The self-report version of the Strengths and Difficulties Questionnaire (SDQ) was administered to two samples of 11-16 year olds: 83 young people in the community and 116 young people attending a mental health clinic. The questionnaire discriminated satisfactorily between the two samples. For example, the clinic mean for the total difficulties score was 1.4 standard deviations above the community mean, with clinic cases being over six times more likely to have a score in the abnormal range. The correlations between self-report SDQ scores and teacher--or parent rated SDQ scores--compared favourably with the average cross informant correlations in previous studies of a range of measures. The self-report SDQ appears promising and warrants further evaluation.

Debt, income and mental disorder in the general population

BACKGROUND

The association between poor mental health and poverty is well known but its mechanism is not fully understood. This study tests the hypothesis that the association between low income and mental disorder is mediated by debt and its attendant financial hardship.

METHOD

The study is a cross-sectional nationally representative survey of private households in England, Scotland and Wales, which assessed 8580 participants aged 16-74 years living in general households. Psychosis, neurosis, alcohol abuse and drug abuse were identified by the Clinical Interview Schedule--Revised, the Schedule for Assessment in Neuropsychiatry (SCAN), the Alcohol Use Disorder Identification Test (AUDIT) and other measures. Detailed questions were asked about income, debt and financial hardship.

RESULTS

Those with low income were more likely to have mental disorder [odds ratio (OR) 2.09, 95% confidence interval (CI) 1.68-2.59] but this relationship was attenuated after adjustment for debt (OR 1.58, 95% CI 1.25-1.97) and vanished when other sociodemographic variables were also controlled (OR 1.07, 95% CI 0.77-1.48). Of those with mental disorder, 23% were in debt (compared with 8% of those without disorder), and 10% had had a utility disconnected (compared with 3%). The more debts people had, the more likely they were to have some form of mental disorder, even after adjustment for income and other sociodemographic variables. People with six or more separate debts had a six-fold increase in mental disorder after adjustment for income (OR 6.0, 95% CI 3.5-10.3).

CONCLUSIONS

Both low income and debt are associated with mental illness, but the effect of income appears to be mediated largely by debt.

Prevalence of pervasive developmental disorders in the British nationwide survey of child mental health

OBJECTIVE

The prevalence of pervasive developmental disorders (PDD) is not well established and needs monitoring. The prevalence of PDD in the 1999 nationwide British survey of child and adolescent mental health was investigated.

METHOD

A randomized, stratified sample of children (N= 12,529) aged 5 to 15 years was generated from the Child Benefit Register. Trained interviewers interviewed parents and youths aged 11 or older with a standardized diagnostic interview (Development and Well-Being Assessment), and questionnaire data (Strengths and Difficulties Questionnaire) were obtained from teachers and parents, who also completed self-report measures of psychological distress. Final diagnostic determination was achieved by a team of experienced clinicians using all data sources.

RESULTS

A total of 10,438 (83%) interviews were conducted. There were 2 girls with Rett syndrome (weighted prevalence: 3.8/10,000 girls) and 27 children with other PDD (weighted prevalence: 26.1/10,000). Compared with children with a psychiatric disorder other than PDD, social but not behavioral problems were more frequent in the PDD group. Parents of children with PDD had higher rates of psychological distress than those from the two comparison groups.

CONCLUSIONS

Consistent with other recent surveys, PDD rates are higher than those reported 30 years ago. The burden associated with PDD is very high.

Unequal access and unmet need: neurotic disorders and the use of primary care services

BACKGROUND

In this paper we use data from the National Survey of Psychiatric Morbidity to examine how many people with neurotic disorders receive professional evaluation, and how this is affected by clinical and sociodemographic differences. We hypothesized that psychiatric symptoms and attendant dysfunctions would both have an effect on contacting, and that key demographic variables would not.

METHOD

The household component of the British National Surveys of Psychiatric Morbidity was based on a random sample of > 10,000 subjects. Psychiatric symptoms and ICD-10 diagnosis were established by lay interviewers using the CIS-R. Social dysfunction was tapped by asking about difficulties in performing seven types of everyday activity. We examined symptom score, ADL deficit score and demographic variables in relation to contact with primary care physicians for psychiatric symptoms.

RESULTS

The major determinant of contacting a primary care physician was severity, mainly due to the level of psychiatric symptoms, but with an independent contribution from social dysfunction. There were also significant contributions from sex, marital status, age, employment status and whether the subject had a physical condition as well.

CONCLUSIONS

The major influence on whether people seek the help of their family doctors for mental health problems is the severity of disorder. Although there are some social inequalities in access to family doctors, these are less important. The most salient finding from our study is that even people suffering from high levels of psychiatric symptoms very often do not have contact with professionals who might help them.

Urban-rural mental health differences in great Britain: findings from the national morbidity survey

BACKGROUND

Studies of urban-rural differences in prevalence of non-psychotic mental disorder have not given consistent findings. Such differences have received relatively little study in Great Britain.

METHODS

Data from 9777 subjects in the Household Survey of the National Morbidity Survey of Great Britain were analysed for differences between urban, semi-rural and rural areas. Psychiatric morbidity was assessed by scores on the Revised Clinical Interview Schedule (CIS-R), together with alcohol dependence, drug dependence, receipt of treatment from general practitioners. Associations with other characteristics were examined by logistic regression.

RESULTS

Urban subjects had higher rates than rural of CIS-R morbidity, alcohol dependence and drug dependence, with semi-rural subjects intermediate. Urban subjects also tended to be members of more deprived social groups, with more adverse living circumstances and greater life stress, factors themselves associated with disorder. Urban-rural differences in alcohol and drug dependence were no longer significant after adjustment for these factors by logistic regression, and differences on CIS-R morbidity were considerably reduced. There were no differences in treatment.

CONCLUSIONS

There are considerable British urban rural differences in mental health, which may largely be attributable to more adverse urban social environments.

2D and 3D high resolution gradient echo functional imaging of the brain: venous contributions to signal in motor cortex studies

Recent emphasis on high resolution gradient echo studies in functional imaging has led to the conclusion that there are likely three domains of response to the blood circulation in the brain when considering field inhomogeneity effects of the venous blood pre- and during activation. The first is a coherent effect due to large or macroscopic vessels on the order of the size of the voxel (ca 200-500 microns in most studies). These can lead to very large signal changes (up to 100%). The second is at the venule level (ca 50-200 microns) and is associated with smaller parenchymal changes (usually ca 10% or less). The third is at the capillary level and is associated with much smaller signal changes at 1.5 T and even up to 4 T. The actual signal changes depend on field strength and sequence design. In this paper, we present our experience in detecting the first two domains with 2D and 3D gradient echo imaging at 1.5 T. We find that high resolution enables visualization of the larger small veins in motor cortex studies and that, on occasion, it is possible to see the venule effects as well. We suggest a simple model to explain the large signal changes based on susceptibility changes and partial volume effects. Comparisons of the functional imaging data to this model and to MR angiographic studies are also shown as evidence of the venous sources of the susceptibility changes.

A general population comparison of the Composite International Diagnostic Interview (CIDI) and the Schedules for Clinical Assessment in Neuropsychiatry (SCAN)

BACKGROUND

In psychiatric surveys of the general population, there has been considerable discrepancy between diagnoses obtained by fully structured interviews and those established by systematic semi-structured clinical evaluation. The Composite International Diagnostic Interview (CIDI) is an example of the first type of interview widely used in general population surveys. We compared its performance in diagnosing current depressive and anxiety disorders with the Schedules for Clinical Assessment in Neuropsychiatry (SCAN), a semi-structured diagnostic interview administered by clinically trained interviewers.

METHODS

Household addresses in Leicestershire, UK, were randomly sampled and 860 adults were screened with the Revised Clinical Interview Schedule. Adults with too few symptoms to fulfil diagnostic criteria for study disorders were excluded to increase the proportion re-interviewed who met such criteria. Repeat diagnostic interviews with the CIDI and SCAN, ordered randomly, were sought from eligible screen positive respondents. Recalibrated CIDI prevalence estimates were derived from the SCAN classification using Bayesian statistics.

RESULTS

Concordance ranged between 'poor' and 'fair' across almost all types of study disorders, and for co-morbidity. Concordance was somewhat better for severity of depression and when lower diagnostic thresholds were used for depression. Interview order effects were suggested with lower concordance when CIDI followed SCAN. Recalibration reduced the prevalence of depressive or anxiety disorder from 9.0 to 6.2%.

CONCLUSIONS

Community psychiatric surveys using structured diagnostic interview data must be interpreted cautiously. They should include an element of clinical re-appraisal so findings can be adjusted for estimation differences between fully structured and clinical assessments.

The influence of age and sex on the prevalence of depressive conditions: report from the National Survey of Psychiatric Morbidity

Women are consistently reported to have a greater prevalence of depressive disorders than men. The reason for this is unclear, and is as likely to be social as biological. There is some evidence that the excess of depression is greater during women's reproductive lives. Data from the National Survey of Psychiatric Morbidity were used to test the hypothesis that the excess disappeared in the post-menopausal years and that obvious social explanations for this were inadequate. Subjects (n = 9792) from a random sample of the British population provided data for the analysis. Lay interviewers using the CIS-R carried out psychiatric assessment. Subjects with ICD-10 depressive episode or mixed anxiety/depression were compared with the remainder. Social variables that were likely to contribute to a post-menopausal decline in depressive disorders were controlled in logistic regression analyses. There was a clear reversal of the sex difference in prevalence of depression in those over age 55. This could not be explained in terms of differential effects of marital status, childcare, or employment status. This large and representative survey adds considerably to the increasingly held view that the sex difference in prevalence of depression is less apparent in later middle age. This may be linked to the menopause, and our attempts to explain it in terms of obvious conditions among social variables were not successful. More specific studies are required to clarify the finding.

Psychosis and drug dependence: results from a national survey of prisoners

BACKGROUND

The links between drug use and psychosis are of major aetiological and prognostic significance. Psychosis and drug dependence frequently co-occur within the prison population, providing the opportunity to study this link more closely.

AIMS

To explore the relationship between psychosis and drug dependence in a sample of prisoners.

METHOD

A total of 3142 prisoners were surveyed nationally, and structured clinical data were obtained from a subsample of 503 respondents. Psychiatric assessment was based on the Schedules for Clinical Assessment in Neuropsychiatry (version 1.0). Measures of amphetamine, cannabis, cocaine and heroin use and dependence were obtained through self-report.

RESULTS

Logistic regression analyses indicated that first use of amphetamines or cocaine before the age of 16 years and severe cannabis or cocaine dependence were related to an increased risk of psychosis. In contrast, severe dependence on heroin was associated with a reduced risk of this classification.

CONCLUSIONS

Severe dependence on cannabis and psychostimulants is associated with a higher risk of psychosis and is in contrast to severe dependence on heroin, which has a negative relationship with psychosis.

Cortical localization of human sustained attention: detection with functional MR using a visual vigilance paradigm

PURPOSE

Our goal was to determine whether functional MRI on a standard 1.5 T system can localize activation during a visual vigilance sustained attention task and whether this corresponds to results described in a PET investigation of a similar task.

METHOD

Sixteen volunteers were studied on a 1.5 T system using a gradient echo technique. A single axial section was oriented within a stereotaxic coordinate space, 40 mm superior to the anterior-posterior commissure line. Images with eyes closed were followed by images during subject concentration on a small dim spot. Motion correction and pixel-by-pixel statistical analysis were performed. Talairach grids were applied for summary statistical analysis and comparison to PET data, with analysis using a series of planned contrasts within a repeated measures analysis of variance.

RESULTS

Predominantly right-sided frontal and parietal activation was observed, with statistical significance across subjects in the right frontal lobe (F > or = 5.9, p < or = 0.041). Comparison with previously reported PET data yielded a very similar pattern of activation (F = 13.2; df = 1,8; p = 0.007).

CONCLUSION

Activation of the right middle frontal gyrus and right parietal lobe during visual vigilance is detectable across functional imaging modalities.