Dynamic and Static Cognitive Deficits in Schizophrenia and Bipolar Disorder After the First Episode.

Few studies have comprehensively examined the profile of cognitive functioning in first episode psychosis patients throughout the lifespan, and from first episode to chronic stage. We assessed functioning in general and specific cognitive functions, comparing both schizophrenia (N = 64) and bipolar I (N = 19) patients to controls (N = 103). Participants were from a population-based, case-control study of first episode psychosis patients, who were followed prospectively up to 10 years post first admission.

Cognitive Change in Schizophrenia and Other Psychoses in the Decade Following the First Episode.

Objective: Schizophrenia is associated with a marked cognitive impairment that is widely believed to remain stable after illness onset. Yet, to date, 10-year prospective studies of cognitive functioning following the first episode with good methodology are rare. The authors examined whether schizophrenia patients experience cognitive decline after the first episode, whether this decline is generalized or confined to individual neuropsychological functions, and whether decline is specific to schizophrenia.

Neuropsychological function at first episode in treatment-resistant psychosis: findings from the ÆSOP-10 study.

Background: Neuropsychological investigations can help untangle the aetiological and phenomenological heterogeneity of schizophrenia but have scarcely been employed in the context of treatment-resistant (TR) schizophrenia. No population-based study has examined neuropsychological function in the first-episode of TR psychosis.

Methods: We report baseline neuropsychological findings from a longitudinal, population-based study of first-episode psychosis, which followed up cases from index admission to 10 years.

Gender differences in neuropsychological performance across psychotic disorders--a multi-centre population based case-control study.

Background: Patients with schizophrenia and other psychoses exhibit a wide range of neuropsychological deficits. An unresolved question concerns whether there are gender differences in cognitive performance.

Methods: Data were derived from a multi-centre population based case-control study of patients with first-episode psychosis.

Differential relationship between neurological and cognitive dysfunction in first episode psychosis patients and in healthy individuals.

The minor neurological and cognitive deficits consistently reported in psychoses may reflect the same underlying brain dysfunction. Still, even in healthy individuals minor neurological abnormalities are associated with worse cognitive function. Therefore, establishing which neurological and cognitive deficits are specific to psychosis is essential to inform the pathophysiology of this disorder.

Linear and non-linear associations of symptom dimensions and cognitive function in first-onset psychosis.

Background: Associations between symptom dimensions and cognition have been mainly studied in non-affective psychosis. The present study investigated whether previously reported associations between cognition and four symptom dimensions (reality distortion, negative symptoms, disorganisation and depression) in non-affective psychosis generalise to a wider spectrum of psychoses. It also extended the research focus to mania, a less studied symptom dimension.

Is there a link between childhood trauma, cognition, and amygdala and hippocampus volume in first-episode psychosis?

Patients with psychosis have higher rates of childhood trauma, which is also associated with adverse effects on cognitive functions such as attention, concentration and mental speed, language, and verbal intelligence. Although the pathophysiological substrate for this association remains unclear, these cognitive deficits may represent the functional correlate of changes observed in relation to trauma exposure in structures such as the amygdala and the hippocampus. Interestingly, these structures are often reported as altered in psychosis.

Childhood trauma and cognitive function in first-episode affective and non-affective psychosis.

Background: A history of childhood trauma is reportedly more prevalent in people suffering from psychosis than in the general population. Childhood trauma has also been linked to cognitive abnormalities in adulthood, and cognitive abnormalities, in turn, are one of the key clinical features of psychosis. Therefore, this study investigated whether there was a relationship between childhood trauma and cognitive function in patients with first-episode psychosis.

Criminal offending and distinguishing features of offenders among persons experiencing a first episode of psychosis.

Aims: Persons with severe mental illness (SMI) are at increased risk of criminal offending, particularly violent offending, as compared with the general population. Most offenders with SMI acquire convictions prior to contact with mental health services. This study examined offending among 301 individuals experiencing their first episode of psychosis.

Specific and generalized neuropsychological deficits: a comparison of patients with various first-episode psychosis presentations.

Objective: Overwhelming evidence suggests that compromised neuropsychological function is frequently observed in schizophrenia. Neurocognitive dysfunction has often been reported in other psychotic disorders, although there are inconsistencies in the literature. In the context of four distinct diagnostic groups, the authors compared neuropsychological performance among patients experiencing their first psychotic episode.

Neuropsychological functioning in first-episode schizophrenia.

Background: Identifying neurocognitive subtypes in schizophrenia may help establish neurobiologically meaningful subtypes of the disorder, but is frequently confounded by differences in intellectual function between individuals with schizophrenia and controls.

Aims: To examine neuropsychological performance in individuals with epidemiologically based, first-onset schizophrenia and intellectually matched controls.

Method: Using standard IQ and reading tests, we examined the proportions of 101 people with epidemiologically derived, first-onset schizophrenia/schizoaffective disorder and 317 community controls, falling into three a priori defined intellectual categories: 'stable good', 'deteriorated poor' and 'stable poor'.

Neuropsychological correlates of eye movement abnormalities in schizophrenic patients and their unaffected relatives.

Impairments on neuropsychological and eye movement tasks have been demonstrated in schizophrenic patients and also reported in their unaffected relatives. However, it is not clear to what extent these phenotypes overlap. This study examined the relationship between specific eye movement and neuropsychological measures.

Selective deficits in semantic verbal fluency in patients with a first affective episode with psychotic symptoms and a positive history of mania.

Objectives: Neurocognitive dysfunction is likely to represent a trait characteristic of bipolar disorder, but the extent to which it comprises 'core' deficits as opposed to those secondary to longstanding illness or intellectual decline is unclear. We investigated neuropsychological performance in an epidemiologically derived sample of patients with a first affective episode with psychotic symptoms and a positive history of mania, compared to community controls.

Methods: Using a nested case-control, population-based study, measures of episodic and working memory, executive function, processing speed, and visual-spatial perception were compared between 35 patients with a first affective episode with psychotic symptoms and a positive history of mania, and 274 community controls, as well as a subgroup of 105 controls matched on current IQ ('good' versus 'poor') and IQ trajectory ('stable', 'declined', or 'improved') with the patients (three controls per case).

Neurological abnormalities and cognitive ability in first-episode psychosis.

Background: It remains unclear if the excess of neurological soft signs, or of certain types of neurological soft signs, is common to all psychoses, and whether this excess is simply an epiphenomenon of the lower general cognitive ability present in psychosis.

Aims: To investigate whether an excess of neurological soft signs is independent of diagnosis (schizophrenia v. affective psychosis) and cognitive ability (IQ).

Duration of untreated psychosis and neuropsychological function in first episode psychosis.

Purpose: We investigated whether duration of untreated psychosis (DUP) prior to first presentation was associated with cognitive function in first episode psychosis (FEP) subjects. We predicted that longer DUP would be associated with greater neurocognitive impairment.

Method: 180 subjects with schizophrenia (and 93 subjects with Other Psychoses) performed a neurocognitive battery assessing IQ, verbal learning, working memory, visual learning and speed of processing.

Saccadic distractibility is elevated in schizophrenia patients, but not in their unaffected relatives.

Background: Saccadic distractibility, as measured by the antisaccade task, has attracted attention as a putative endophenotypic marker for schizophrenia. Some studies have suggested that this measure is elevated in the unaffected relatives of schizophrenia patients. However, recent studies have called this into question and the topic remains controversial.

Eye tracking in schizophrenia: does the antisaccade task measure anything that the smooth pursuit task does not?

Smooth pursuit and antisaccade eye-tracking abnormalities have been proposed as endophenotypes for schizophrenia. However, it is not clear whether these tasks measure the same underlying abnormality. We hypothesised that these measures would be correlated.

The relationship between eye movement and brain structural abnormalities in patients with schizophrenia and their unaffected relatives.

Schizophrenia is associated with subtle eye movement and brain structural abnormalities, but the extent to which these abnormalities occur in the same individuals is unclear. The relationship between quantitative measures of eye movement task performance (smooth pursuit and antisaccade) and MRI volumetric measurements (whole brain volume, prefrontal region, lateral ventricles, third ventricle, hippocampus, and cerebellum) was assessed in 70 patients with schizophrenia or schizoaffective disorder, 105 of their unaffected first-degree relatives and 68 controls. There was a lack of correlation between eye movement and morphometric abnormalities suggesting largely separable neurobiological pathways underlying the morphological and the eye movement deviations that have previously been identified in these patients.

A developmental model for similarities and dissimilarities between schizophrenia and bipolar disorder.

Schizophrenia and mania have a number of symptoms and epidemiological characteristics in common, and both respond to dopamine blockade. Family, twin and molecular genetic studies suggest that the reason for these similarities may be that the two conditions share certain susceptibility genes. On the other hand, individuals with schizophrenia have more obvious brain structural and neuropsychological abnormalities than those with bipolar disorder; and pre-schizophrenic children are characterised by cognitive and neuromotor impairments, which are not shared by children who later develop bipolar disorder.

Meta-analysis of magnetic resonance imaging brain morphometry studies in bipolar disorder.

Background: Several studies assessing volumetric measurements of regional brain structure in bipolar disorder have been published in recent years, but their results have been inconsistent. Our aim was to complete a meta-analysis of regional morphometry in bipolar disorder as assessed using magnetic resonance imaging (MRI).

Methods: We conducted a systematic literature search of MRI studies of bipolar disorder and identified studies which reported volume measurements in a selected number of regions.