Predictors of cognition in first episode psychosis

Verbal memory measurement towards digital perspectives in first-episode psychosis: A review

BACKGROUND

Even in the early phases of psychotic spectrum illnesses such as schizophrenia, patients can experience cognitive decline or deficits prior to the onset of psychotic symptoms such as delusions and hallucinations. In this systematic review, we assessed which verbal memory assessments are most widely used in first-episode psychosis and may be applied via digital technologies (smartphone applications, etc.) for use in early detection.

METHODS

In November 2019, we searched for studies measuring verbal memory in first episode psychosis or schizophrenia over the past 10 years on PubMed and PsycINFO. We screened abstracts of these studies and excluded review studies. Full-texts of included studies were used to identify the verbal memory measurement tests, follow-up frequencies, and sample sizes.

RESULTS

We screened 233 reports and found that 120 original research studies measured verbal memory in first episode psychosis over the past 10 years. Four of these studies specified using a computer, 24 (20%) used a paper-pen format, 1(1%) used both, and 91 (76%) studies did not specify their administration tools or suggest there were offered in digital formats. Thirty-five (30%) studies had follow-up measurements of verbal memory, while 85 (70%) had only a single verbal memory measurement.

DISCUSSION

While many scales are commonly used to measure verbal memory in first episode psychosis, they are not often administered via digital technology. There is an emerging opportunity to administer these and other tests via digital technologies for expanding access to early detection of cognitive decline in clinical high risk and first-episode psychosis.

Intersection of verbal memory and expressivity on cortical contrast and thickness in first episode psychosis

BACKGROUND

Longitudinal studies of first episode of psychosis (FEP) patients are critical to understanding the dynamic clinical factors influencing functional outcomes; negative symptoms and verbal memory (VM) deficits are two such factors that remain a therapeutic challenge. This study uses white-gray matter contrast at the inner edge of the cortex, in addition to cortical thickness, to probe changes in microstructure and their relation with negative symptoms and possible intersections with verbal memory.

METHODS

T1-weighted images and clinical data were collected longitudinally for patients (N = 88) over a two-year period. Cognitive data were also collected at baseline. Relationships between baseline VM (immediate/delayed recall) and rate of change in two negative symptom dimensions, amotivation and expressivity, were assessed at the behavioral level, as well as at the level of brain structure.

RESULTS

VM, particularly immediate recall, was significantly and positively associated with a steeper rate of expressivity symptom decline (r = 0.32, q = 0.012). Significant interaction effects between baseline delayed recall and change in expressivity were uncovered in somatomotor regions bilaterally for both white-gray matter contrast and cortical thickness. Furthermore, interaction effects between immediate recall and change in expressivity on cortical thickness rates were uncovered across higher-order regions of the language processing network.

CONCLUSIONS

This study shows common neural correlates of language-related brain areas underlying expressivity and VM in FEP, suggesting deficits in these domains may be more linked to speech production rather than general cognitive capacity. Together, white-gray matter contrast and cortical thickness may optimally inform clinical investigations aiming to capture peri-cortical microstructural changes.

The effect of second-generation antipsychotics on basal ganglia and thalamus in first-episode psychosis patients

Patients who have recently experienced a first of episode psychosis (FEP) exhibit considerable heterogeneity in subcortical brain volumes. These results become even more divergent when exploring the effect of antipsychotic medication among other clinical and cognitive features. We aimed to contrast volumetric measures in basal ganglia and thalamus in patients with a FEP treated with different second-generation antipsychotics. T1-weighted magnetic resonance images were obtained and subcortical structures were extracted with MAGeT-Brain. Relationships with cognitive functioning were also explored with a Global Cognitive Index obtained, on average, within one month from the scan. Subgroups included: risperidone (n = 26), aripiprazole (n = 22), olanzapine (n = 19) and controls (n = 80). The olanzapine subgroup displayed significant enlargement of the right globus pallidus volume compared with all other groups. Moreover, despite not exhibiting poorer cognitive capacity than the rest of patients, results from a stepwise multiple-regression linear regression analysis identified a significant negative association between right globus pallidus volume and scores on the Global Cognitive Index among these patients. To our knowledge, this is the first study to associate treatment with olanzapine with an increase in globus pallidus volume in a sample of FEP patients with a relatively short time of antipsychotic monotherapy. Such enlargement was also found to be associated with poorer global cognitive functioning. Exploration of the biological underpinnings of this early medication-induced enlargement should be the focus of future investigations since it may lend insight towards achieving a better clinical outcome for these patients.

Gender differences in correlates of cognition in first-episode psychosis

Studies of gender cognitive differences in schizophrenia have reported mixed results. This study examined cognitive correlates including demographics, symptoms and functioning in men and women in a large sample of first-episode adult-onset psychosis patients. Detailed demographic, clinical and functioning data were collected from 360 first-episode patients upon admission into an early intervention service for psychotic disorders. They were also administered a comprehensive neurocognitive battery. Correlation analyses showed that memory and working memory were more significantly associated with onset age, negative symptoms and side effects in women. Processing speed correlated with antipsychotic dosage in men and side effects in women. Selective attention correlated with reality distortion and negative symptoms in women, and onset age and education in men. Executive function correlated with onset age and reality distortion in women. All cognitive domains significantly correlated with educational level and functioning in both genders. Negative symptoms explained significant variability in cognition in both genders, while reality distortion, side effects and affective symptoms were significant factors that differentiated between genders. Although there are similarities in cognitive deficits, considerable heterogeneity exists in associations of symptoms and cognition in men and women. Results facilitate individualised tailoring of interventions, including cognitive remediation therapy.

Pathways to functional outcomes following a first episode of psychosis: The roles of premorbid adjustment, verbal memory and symptom remission

OBJECTIVE

Most studies have investigated either the singular or relative contributions of premorbid adjustment, verbal memory and symptom remission to functional outcomes in first-episode psychosis. Fewer studies have examined the pathways of these factors in impacting functioning. Our study addresses this gap. The objective was to determine whether the relationship between premorbid adjustment and functional outcomes was mediated by verbal memory and symptom remission.

METHOD

A total of 334 first-episode psychosis participants (aged 14-35 years) were assessed on premorbid adjustment, verbal memory upon entry, and positive and negative symptom remission and functioning at multiple time points over a 2-year follow-up.

RESULTS

Mediation analyses showed that over the first year, the relationship between premorbid adjustment and functioning was mediated by verbal memory and positive symptom remission (β = -0.18; 95% confidence interval = [-0.51, -0.04]), as well as by verbal memory and negative symptom remission (β = -0.41; 95% confidence interval = [-1.11, -1.03]). Over 2 years, the relationship between premorbid adjustment and functioning was mediated by verbal memory and only negative symptom remission (β = -0.38; 95% confidence interval = [-1.46, -0.02]).

CONCLUSION

Comparatively less malleable factors (premorbid adjustment and verbal memory) may contribute to functional outcomes through more malleable factors (symptoms). Promoting remission may be an important parsimonious means to achieving better functional outcomes.

Duration of untreated psychosis and neurocognitive functioning in first-episode psychosis: a systematic review and meta-analysis

BACKGROUND

Previous reviews suggest there is minimal evidence for an association between duration of untreated psychosis (DUP) and neurocognition. This is based on tallied findings of studies with small samples and neurocognition viewed as a single construct. We aimed to conduct a systematic review and meta-analysis examining the association between DUP and individual neurocognitive domains and tests in first-episode psychosis (FEP).

METHOD

MOOSE and PRISMA guidelines were followed. Forty-three studies involving 4647 FEP patients were included. For studies providing correlations between DUP and neurocognition, 12 separate meta-analyses were performed based on neurocognitive domains/indices. The influence of demographic/clinical variables was tested using weighted linear meta-regression analyses.

RESULTS

The relationship between DUP and most neurocognitive domains/indices was not significant. Longer DUP was associated with a larger cognitive deterioration index, i.e. current minus premorbid intellectual functioning (N = 4; mean ES -0.213, 95% confidence interval (CI) (-0.344 to -0.074), p = 0.003). Findings were homogeneous, with no evidence of publication bias or significant influence from moderators. For studies providing mean and standard deviations for neurocognitive measures and DUP, 20 meta-regressions were performed on individual neurocognitive tests. One significant finding emerged showing that longer DUP was associated with fewer Wisconsin Card Sorting Test-perseverative errors (mean ES -0.031, 95% CI (-0.048 to -0.013), p < 0.001). Exploratory meta-regressions in studies with mean DUP <360 days showed longer DUP was significantly associated with poorer performance on Trail Making Test A and B and higher Full-Scale IQ.

CONCLUSION

There may not be a generalised association between DUP and neurocognition, however, specific cognitive functions may be associated with longer DUP or delayed help-seeking.

Duration of untreated psychosis and neurocognition in first-episode psychosis: A meta-analysis

Neurocognitive impairment is a well-established feature of first-episode psychosis (FEP). Neurotoxicity hypothesis of psychosis suggests that untreated psychosis before the initiation of first effective treatment is associated with loss of acquired cognitive abilities. However, the outcome of the studies investigating the relationship between duration of untreated psychosis (DUP) and cognitive impairment in FEP remains inconclusive. No previous meta-analysis investigating the relationship between DUP and cognitive impairment in FEP has been published. Following the systematic review of FEP studies, a random-effects meta-analysis of the relationship between DUP and neurocognition in schizophrenia was conducted. Current meta-analysis included 27 studies including 3127 patients with first-episode psychosis. Overall, DUP and cognitive abilities were not significantly related, with the exception of evidence for a weak relationship with a single cognitive domain. There was a very small but significant association between longer DUP and reduced performance in planning/problem-solving ability (r=-0.09, CI=-0.14 to -0.03). Current findings do not provide support for the neurotoxicity hypothesis of psychosis.

The effects of cannabis on memory function in users with and without a psychotic disorder: findings from a combined meta-analysis

BACKGROUND

Effect of cannabis use on memory function is a contentious issue, with effects being different in healthy individuals and patients with psychosis.

METHOD

Employing a meta-analytic approach we investigated the effects of cannabis use on memory function in patients with psychosis and healthy individuals, and the effect of diagnosis, memory dimension and moderating factors. A total of 88 studies were identified through a systematic literature search, investigating healthy (n = 7697) and psychotic (n = 3261) individuals. Standardized mean differences between the cannabis user and non-user groups on memory tasks were estimated using random-effects models and the effect-size statistic Cohen's d. Effects of potential moderating factors were tested using mixed-effects models and subgroup analyses.

RESULTS

We found that cannabis use was associated with significantly (p ⩽ 0.05) impaired global (d = 0.27) and prospective memory (d = 0.61), verbal immediate (d = 0.40) and delayed (d = 0.36) recall as well as visual recognition (d = 0.41) in healthy individuals, but a better global memory (d = -0.11), visual immediate recall (d = -0.73) and recognition (d = -0.42) in patients. Lower depression scores and younger age appeared to attenuate the effects of cannabis on memory. Cannabis-using patients had lower levels of depression and were younger compared with non-using patients, whilst healthy cannabis-users had higher depression scores than age-matched non-users. Longer duration of abstinence from cannabis reduced the effects on memory in healthy and patient users.

CONCLUSIONS

These results suggest that cannabis use is associated with a significant domain-specific impairment in memory in healthy individuals but not in cannabis-using patients, suggesting that they may represent a less developmentally impaired subgroup of psychotic patients.

Relationship between neurocognition and functional recovery in first-episode schizophrenia: Results from the second year of the Oslo multi-follow-up study

Lack of control of confounding variables, high attrition rate, and too few neurocognitive domains completed at each assessment point are some of the limitations identified in studies of the relationship between cognition and functional outcome in schizophrenia. In the ongoing Oslo multi-follow-up study 28 first episode schizophrenia patients and a pairwise matched control group (N=28) are assessed with the MATRICS Consensus Cognitive Battery (MCCB), a clinical interview, an inventory on social and role functioning and criteria of remission and recovery at several follow-up points. The current paper describes the rate of remission and full recovery, and investigates the relationship between neurocognition and functional outcome. At 2-year follow-up, 80.0% of the patients were in remission and 16.0% of them fulfilled the criteria for full recovery. The attrition rate was very low. In the follow-up period, there was a statistically significant decline in Verbal Learning and a significant improvement on Reasoning/Problem Solving and Social Cognition in the schizophrenia group, but not in the control group. This indicates a differentiated neurocognitive course. In the schizophrenia group, Attention/Vigilance and years of education at baseline were significant predictors of social and role functioning 2 years later.

Cognition and the prediction of functioning in patients with a first treated episode of psychosis: a prospective study

Past research on the role of cognitive performance in predicting later psychosocial functioning for individuals with first treated episode of a psychotic disorder has yielded inconsistent results. Several factors have been suggested as determining the strength of any such relationship including the type of functioning measured, time of the cognitive assessment, covariates included and the use of global versus specific measures of cognitive functioning. In the current study, we examined the importance of these factors in a five year prospective study of individuals with first episode psychotic disorders. Just over 80% of the sample had a schizophrenia spectrum disorder. Cognitive assessments were carried out after initiation of treatment on 113 patients, and at one year for 79 patients. There was evidence that cognition predicted occupational functioning and use of a disability pension, but not a summary index of functioning or use of supervised housing, at follow-up. Overall I.Q. was a more consistent predictor than measures of specific cognitive functions, and there was evidence that cognition assessed after presentation for treatment, particularly after a year of treatment, was more predictive of later functioning than premorbid I.Q. Cognitive functioning, however, did not add to the prediction of outcomes beyond the level possible using past educational achievement or academic premorbid adjustment.

A longitudinal study on the relationship between duration of untreated psychosis and executive function in early-onset first-episode psychosis

BACKGROUND

The relationship between duration of untreated psychosis (DUP) and executive function (EF) in patients with first-episode psychosis (FEP) is controversial. We aim to assess the influence of DUP on changes in EF over a 2-year period in subjects with early-onset FEP (first psychotic symptom before age 18) and less than 6 months of positive symptoms.

METHODS

A total of 66 subjects were included in the study (19 females [28.8%], mean age 16.2 ± 1.6 years). The influence of DUP on changes in EF over the 2-year follow-up (expressed as a composite score of 5 cognitive abilities: attention, working memory, cognitive flexibility, response inhibition, and problem solving) was estimated using a multivariate linear regression model after removing the effect of intelligence quotient and controlling for age, gender, diagnosis, premorbid adjustment, severity of positive and negative symptoms at baseline, global functioning at baseline, and mean daily antipsychotic dosage during follow-up.

RESULTS

Mean DUP was 65.0 ± 6.9 days (95% confidence interval [CI], 51.2, 78.8). Median DUP was 47.5 days (range 2-180 days). Negative symptoms at baseline was the only variable significantly associated with EF at baseline (10.9% of explained variance [e.v. 10.9%], p=0.007). Only shorter DUP (e.v. 8.7%, p=0.013) and greater severity of baseline negative symptoms (e.v. 10.0%, p=0.008) were significantly associated with greater improvement in EF.

CONCLUSIONS

In early-onset FEP, shorter DUP was associated with greater improvement in EF over a 2-year follow-up period.