Anomalous self-experiences and neurocognitive functioning in adolescents at risk for psychosis: Still no significant associations found between these two vulnerability markers.

BACKGROUND: Anomalous self-experiences (ASEs) and neurocognitive impairments are considered essential domains of vulnerability for developing psychotic disorders. However, little research exists of possible associations between ASEs and neurocognitive functions in individuals at-risk for psychosis. The interconnections between ASEs and neurocognitive impairments should therefore be clarified as much as possible, especially in young individuals at risk. No previous studies have investigated these two fundamental domains in non-help-seeking adolescents at risk for developing psychosis. METHODS: This study is based on the Norwegian Mother, Father and Child Cohort Study (MoBa). Adolescents (N = 48, 94% females, mean age = 15.3) were invited to participate after completing a 14-year-old survey distributed by MoBA. At-risk adolescents were selected based on the 0.4% highest scores on 19 items assessing both psychotic-like experiences and ASEs. Five specifically selected and formulated items measuring ASEs were computed to an ASEs total score. Neurocognitive functioning was assessed using the MATRICS Consensus Cognitive Battery. RESULTS: Regression analyses revealed no significant relationships between ASEs and any neurocognitive domain. CONCLUSIONS: We did not find any significant associations between ASEs and neurocognitive functions in non-help-seeking adolescents at risk for psychotic disorders, which is in line with reports from other types of cohorts. Thus, ASEs and neurocognitive functions may be understood as two relatively separate domains that co-exist in at-risk states. These results underline the need for a wider scope when making predictions about future trajectories, e.g. the development of psychotic disorders. Including both ASEs and neurocognitive functioning in at-risk populations may increase the specificity of vulnerability criteria in this population and enhance our understanding of early psychosis psychopathology.

Perinatal complications and executive dysfunction in early-onset schizophrenia.

BACKGROUND: The present study examined the association between perinatal obstetric complications and executive dysfunction in early-onset schizophrenia (EOS), compared to healthy controls. Higher incidences of obstetric complications and more severe executive dysfunctions characterize EOS. Research shows extensive brain maturation in newborns, suggesting them to be particularly vulnerable for perinatal insults. Executive function is mainly mediated by the prefrontal cortex, an area that matures last during pregnancy. Thus, exposure to perinatal complications may influence executive dysfunction in EOS. METHODS: The participants were 19 EOS patients and 54 healthy controls. Executive function was assessed with the D-KEFS Color Word Interference Test and the Wisconsin Card Sorting Test. Information on perinatal obstetric complications and Apgar 5-min scores were obtained from the Norwegian Medical Birth Registry. Associations between perinatal conditions and executive function were studied using stepwise regression analyses. RESULTS: Perinatal complications, and especially shorter gestational lengths, were significantly associated with significant executive dysfunctions in EOS. Perinatal complications did not affect executive function among healthy controls. A significant relationship between lower Apgar 5-min scores and executive dysfunction was found among both EOS patients and healthy controls. CONCLUSIONS: Exposure to perinatal complications, and particularly a shorter gestational length, was associated with increased executive dysfunction in EOS. Exposed healthy controls did not exhibit similar executive difficulties, suggesting that the EOS patients seemed especially vulnerable for executive deficits due to perinatal insults. The findings indicate that EOS youths learn more slowly and experience more difficulty with problem-solving, which carry important implications for clinical practice. Lower Apgar 5-min scores were associated with executive dysfunction in both groups. Low Apgar score at 5 min may therefore be an important early indicator of executive difficulties among adolescents, independent of diagnosis.

Do clinical characteristics predict the cognitive course in early-onset schizophrenia-spectrum disorders?

BACKGROUND: Being in a period with extensive brain maturation, adolescents with early-onset schizophrenia-spectrum disorders (EOS) provide unique neurodevelopmental data that may contribute to a better understanding of schizophrenia at all ages. Cognitive dysfunction is a central feature of schizophrenia and is more pronounced in EOS than in later onset illness. However, there is limited research on both the long-term course of global cognition in EOS, and how cognition over time is influenced by clinical characteristics during the early illness period. METHODS: Thirty-one EOS patients and 73 controls (age 12-18) were assessed on clinical variables at baseline (PANSS, duration of untreated psychosis [DUP], hospitalizations, suicide attempts, and remission). Neuropsychological assessments with the MATRICS Consensus Cognitive Battery (MCCB) were conducted at baseline and after both 1 and 2 years, and composite scores of total performances were calculated. The analyses were performed with a linear mixed model. RESULTS: The present study found that global cognition followed a stable course over the first years of the disease in EOS, though at a significantly lower level in EOS compared with the controls. We did not detect a relationship between DUP, remission, positive/negative symptoms, and hospitalizations on one hand, and long-term cognition on the other hand, but PANSS-general and suicide attempt history at baseline were identified as risk factors of longitudinal cognitive function. CONCLUSIONS: Though at different levels, the EOS group and the controls had a similar cognitive course over 2 years. Some baseline characteristics (psychotic symptoms, DUP, remission, and hospitalization) had no influence on cognition within the first 2 years of illness. In contrast, general symptoms and a history of suicide attempts at baseline were more potent risk factors of the cognitive course than the psychotic-specific symptoms, and should, therefore, be subject to specific attention in the evaluation and treatment of patients with early-onset psychosis.

Cognitive functioning in a group of adolescents at risk for psychosis.

Cognitive deficits are a core feature of schizophrenia, and impairments are present in groups at-risk for psychosis. Most at-risk studies include young adults and not younger age-groups, such as adolescents. Participants are usually help-seeking individuals, even though risk factors may also be present in non-help seeking adolescents. We aim to explore cognitive functions in a group of non-help-seeking 15-year-old adolescents at risk for psychosis compared to age- and gender matched controls, including particular focus on specific cognitive domains. Hundred participants (mean age = 15.3) were invited after completing the 14-year-old survey distributed by the Norwegian Mother-, Father- and Child Study. At-risk adolescents were selected based on high scores on 19 items assessing both psychotic experiences and anomalous self-experiences. Matched controls were selected from the same sample. Cognitive functioning was assessed using the MATRICS Consensus Cognitive Battery and IQ using Wechsler's Abbreviated Test of Intelligence. We found that the adolescents at-risk for psychosis had significantly poorer scores than controls on the composite score of the MCCB. IQ scores were also significantly lower in the at-risk group. The results highlight general cognitive deficits as central in a group of non-help-seeking adolescents at-risk for psychosis. Results indicate that the development of cognitive impairments starts early in life in at-risk groups. It is still unclear whether specific cognitive domains, such as verbal learning, are related to psychotic symptoms or may be specifically vulnerable to symptoms of depression and anxiety.

A systematic review of premorbid cognitive functioning and its timing of onset in schizophrenia spectrum disorders.

Cognitive impairments are core features of established schizophrenia spectrum disorders (SSD). However, it remains unclear whether specific cognitive functions are differentially impaired pre-onset and at what age these impairments can be detected. The purpose of this review was to elucidate these issues through a systematic summary of results from longitudinal studies investigating impairment in specific cognitive domains as antecedents of SSD. Relevant studies were identified by electronic and manual literature searches and included any original study of cognitive domains any time pre-onset of SSDs that included a control group. Effect sizes were calculated by domain for studies comparing high-risk participants who developed SSD with those who did not. The strongest evidence for impairment pre-onset was for mental processing speed, verbal learning and memory, executive function, and social cognition. Some verbal impairments, like language abilities at age 3 and verbal learning and memory at age 7, may develop as static deficits. Conversely, some non-verbal impairments, like mental processing speed, visuospatial abilities, and visual working memory manifest as developmental lag and become significant later in life. Most effect sizes were small to moderate, except for verbal fluency (d' = 0,85), implying this impairment as central in high-risk participants who develop SSD. The present review documents extensive cognitive impairments pre-onset of SSD, and that these impairments start early in life, in line with the neurodevelopmental hypothesis of schizophrenia. Increased knowledge about cognitive impairments preonset can provide a better basis for understanding the complex pathogenesis of SSD as well as informing cognitive remediation programs.

Gestational length affects neurocognition in early-onset schizophrenia.

Obstetric complications (OC) have been linked to an increased risk for schizophrenia in offspring, especially in early-onset schizophrenia (EOS). Extensive cognitive deficits occur in EOS, although no study has yet to investigate the relationship between OC and cognition in EOS. This study aims to examine the frequency of OC in EOS compared to controls, and also investigates the relationship between OC and neurocognitive dysfunction in the two groups. Nineteen EOS patients and 53 healthy controls were tested with the MATRICS Consensus Cognitive Battery (MCCB), and the cognitive measures were combined with OC data from the Norwegian Birth Registry. The results indicated no group differences in OC in EOS and healthy controls, but a shorter gestational length in the EOS group led to significant decreases in the overall neurocognitive composite score, and in processing speed. This suggests that the poorer neuropsychological performances commonly found in EOS may be partly attributable to the length of gestation. The worsened neurocognitive functioning did not appear among controls, so gestational length had a different impact on the two groups. Our findings indicated that a shorter gestational length did not increase the risk for developing EOS, but did significantly affect the cognitive difficulties in this group.