Psychosis prediction: stratification of risk estimation with information-processing and premorbid functioning variables

BACKGROUND

The period preceding the first psychotic episode is regarded as a promising period for intervention. We aimed to develop an optimized prediction model of a first psychosis, considering different sources of information. The outcome of this model may be used for individualized risk estimation.

METHODS

Sixty-one subjects clinically at high risk (CHR), participating in the Dutch Prediction of Psychosis Study, were assessed at baseline with instruments yielding data on neuropsychology, symptomatology, environmental factors, premorbid adjustment, and neurophysiology. The follow-up period was 36 months.

RESULTS

At 36 months, 18 participants (29.5%) had made a transition to psychosis. Premorbid adjustment (P = .001, hazard ratio [HR] = 2.13, 95% CI = 1.39/3.28) and parietal P300 amplitude (P = .004, HR = 1.27, 95% CI = 1.08/1.45) remained as predictors in the Cox proportional hazard model. The resulting prognostic score (PS) showed a sensitivity of 88.9% and a specificity of 82.5%. The area under the curve of the PS was 0.91 (95% CI = 0.83-0.98, cross-validation: 0.86), indicating an outstanding ability of the model to discriminate between transition and nontransition. The PS was further stratified into 3 risk classes establishing a prognostic index. In the class with the worst social-personal adjustment and lowest P300 amplitudes, 74% of the subjects made a transition to psychosis. Furthermore, transition emerged on average more than 17 months earlier than in the lowest risk class.

CONCLUSIONS

Our results suggest that predicting a first psychotic episode in CHR subjects could be improved with a model including premorbid adjustment and information-processing variables in a multistep algorithm combining risk detection and stratification.

The distribution of self-reported psychotic-like experiences in non-psychotic help-seeking mental health patients in the general population; a factor mixture analysis

PURPOSE

Factor mixture analysis (FMA) and item response mixture models in the general population have shown that the psychosis phenotype has four classes. This study attempted to replicate this finding in help-seeking people accessing mental health services for symptoms of non-psychotic mental disorders.

METHODS

All patients (18-35 years old) referred for non-psychotic mental health problems to the secondary mental healthcare service in The Hague between February 2008 to February 2010 (N = 3,694), were included. Patients completed the Prodromal Questionnaire (PQ). Hybrid latent class analysis was applied to explore the number, size and symptom profiles of the classes.

RESULTS

The FMA resulted in four classes. Class 1 (N = 1,039, 28.1%) scored high on conceptual disorganization, inattention and mood disorder. Patients in Class 2 (N = 619, 16.8%) endorsed almost all PQ-items, were more often screened as being psychotic or at high risk of developing psychosis, without care takers noticing. In Class 3 (N = 1,747, 47.3%) perplexity, paranoia and negative symptoms were more prevalent. Patients were more often at high risk of developing psychosis. Class 4 (N = 286, 7.7%) represented the 'normative' group with low probabilities for all items.

DISCUSSION

The results support the hypothesis that a representation in four classes of psychotic-like experiences can also be applied in a help-seeking population.

Can quantitative EEG measures predict clinical outcome in subjects at Clinical High Risk for psychosis? A prospective multicenter study

BACKGROUND

Prediction studies in subjects at Clinical High Risk (CHR) for psychosis are hampered by a high proportion of uncertain outcomes. We therefore investigated whether quantitative EEG (QEEG) parameters can contribute to an improved identification of CHR subjects with a later conversion to psychosis.

METHODS

This investigation was a project within the European Prediction of Psychosis Study (EPOS), a prospective multicenter, naturalistic field study with an 18-month follow-up period. QEEG spectral power and alpha peak frequencies (APF) were determined in 113 CHR subjects. The primary outcome measure was conversion to psychosis.

RESULTS

Cox regression yielded a model including frontal theta (HR=1.82; [95% CI 1.00-3.32]) and delta (HR=2.60; [95% CI 1.30-5.20]) power, and occipital-parietal APF (HR=.52; [95% CI .35-.80]) as predictors of conversion to psychosis. The resulting equation enabled the development of a prognostic index with three risk classes (hazard rate 0.057 to 0.81).

CONCLUSIONS

Power in theta and delta ranges and APF contribute to the short-term prediction of psychosis and enable a further stratification of risk in CHR samples. Combined with (other) clinical ratings, EEG parameters may therefore be a useful tool for individualized risk estimation and, consequently, targeted prevention.

Quantitative and qualitative symptomatic differences in individuals at Ultra-High Risk for psychosis and healthy controls

Patients at Ultra-High Risk (UHR) for developing a first psychosis vary widely in their symptom presentation and illness course. An important aim in UHR research concerns the characterization of the clinical heterogeneity in this population. We aimed to identify qualitatively and quantitatively different clinical symptom profiles at baseline and at 2-year follow-up in a group of UHR subjects and healthy controls. We employed a Latent Class Factor Analysis (LCFA) to the 19 items of the Structured Interview for Prodromal Syndromes (SIPS) ratings at baseline and at 2-year follow-up in a sample of 147 UHR subjects and 141 controls from the Dutch Prediction of Psychosis Study (DUPS) in the Netherlands. Additionally, a stepwise logistic regression analysis was performed with transition to psychosis as a dependent variable and baseline latent variable scores as predictors. Variation in symptomatology at baseline was explained by both quantitative and qualitative differences; at 2-year follow-up qualitative differences between individuals were no longer observed. Quantitative differences showed moderate stability over time (range=0.109-0.42). Within the UHR sample, transition to psychosis was significantly associated with quantitative differences in baseline SIPS scores. The results of our study suggest a 'quasi'-continuous extended psychosis phenotype, a finding that merits replication in other samples.

Psychosocial outcome in patients at clinical high risk of psychosis: a prospective follow-up

PURPOSE

In patients at clinical high risk (CHR) of psychosis, transition to psychosis has been the focus of recent studies. Their broader outcome has received less attention. We studied psychosocial state and outcome in CHR patients.

METHODS

In the European Prediction of Psychosis Study, 244 young help-seeking CHR patients were assessed with the Strauss and Carpenter Prognostic Scale (SCPS) at baseline, and 149 (61.1%) of them were assessed for the second time at the 18-month follow-up. The followed patients were classified into poor and good outcome groups.

RESULTS

Female gender, ever-married/cohabitating relationship, and good working/studying situation were associated with good baseline SCPS scores. During follow-up, patients' SCPS scores improved significantly. Good follow-up SCPS scores were predicted by higher level of education, good working/studying status at baseline, and white ethnicity. One-third of the followed CHR patients had poor global outcome. Poor working/studying situation and lower level of education were associated with poor global outcome. Transition to psychosis was associated with baseline, but not with follow-up SCPS scores or with global outcome.

CONCLUSION

The majority of CHR patients experience good short-term recovery, but one-third have poor psychosocial outcome. Good working situation is the major indicator of good outcome, while low level of education and non-white ethnicity seem to be associated with poor outcome. Transition to psychosis has little effect on psychosocial outcome in CHR patients. In treating CHR patients, clinicians should focus their attention on a broader outcome, and not only on preventing transition to psychosis.

[Prevention of psychotic disorders; is the time ripe for intervention?]

A growing number of research papers focus on the identification of young individuals meeting 'ultra-high risk criteria' for developing a first episode of psychosis. Intervention in this early phase might possibly prevent or postpone the development of a full-blown psychosis. Different detection and treatment strategies within this target group are being discussed. This is illustrated using three cases. The first is a 20-year-old female with subclinical psychotic symptoms and recent functional decline; however, as her symptoms only presented following drug abuse, she was not considered to be at ultra-high risk for developing a first episode of psychosis. The second case involves a 17-year-old student who did meet at-risk criteria; after seeking help for subclinical psychotic symptoms and increasing social withdrawal behaviour his symptoms decreased with help of CBT. The third case, an 18-year-old male, illustrates that specialized investigation into high-risk symptoms of psychosis are sometimes needed to reveal frank psychotic symptoms.

The Strauss and Carpenter Prognostic Scale in subjects clinically at high risk of psychosis

OBJECTIVE

To investigate the predictive value of the Strauss and Carpenter Prognostic Scale (SCPS) for transition to a first psychotic episode in subjects clinically at high risk (CHR) of psychosis.

METHOD

Two hundred and forty-four CHR subjects participating in the European Prediction of Psychosis Study were assessed with the SCPS, an instrument that has been shown to predict outcome in patients with schizophrenia reliably.

RESULTS

At 18-month follow-up, 37 participants had made the transition to psychosis. The SCPS total score was predictive of a first psychotic episode (P < 0.0001). SCPS items that remained as independent predictors in the Cox proportional hazard model were as follows: most usual quality of useful work in the past year (P = 0.006), quality of social relations (P = 0.006), presence of thought disorder, delusions or hallucinations in the past year (P = 0.001) and reported severity of subjective distress in past month (P = 0.003).

CONCLUSION

The SCPS could make a valuable contribution to a more accurate prediction of psychosis in CHR subjects as a second-step tool. SCPS items assessing quality of useful work and social relations, positive symptoms and subjective distress have predictive value for transition. Further research should focus on investigating whether targeted early interventions directed at the predictive domains may improve outcomes.

The validity of the 16-item version of the Prodromal Questionnaire (PQ-16) to screen for ultra high risk of developing psychosis in the general help-seeking population

In order to bring about implementation of routine screening for psychosis risk, a brief version of the Prodromal Questionnaire (PQ; Loewy et al., 2005) was developed and tested in a general help-seeking population. We assessed a consecutive patient sample of 3533 young adults who were help-seeking for nonpsychotic disorders at the secondary mental health services in The Hague with the PQ. We performed logistic regression analyses and CHi-squared Automatic Interaction Detector decision tree analysis to shorten the original 92 items. Receiver operating characteristic curves were used to examine the psychometric properties of the PQ-16. In the general help-seeking population, a cutoff score of 6 or more positively answered items on the 16-item version of the PQ produced correct classification of Comprehensive Assessment of At-Risk Mental State (Yung et al., 2005) psychosis risk/clinical psychosis in 44% of the cases, distinguishing Comprehensive Assessment of At-Risk Mental States (CAARMS) diagnosis from no CAARMS diagnosis with high sensitivity (87%) and specificity (87%). These results were comparable to the PQ-92. The PQ-16 is a good self-report screen for use in secondary mental health care services to select subjects for interviewing for psychosis risk. The low number of items makes it quite appropriate for screening large help-seeking populations, thus enhancing the feasibility of detection and treatment of ultra high-risk patients in routine mental health services.

Cognitive behavioral therapy for subjects at ultrahigh risk for developing psychosis: a randomized controlled clinical trial

BACKGROUND

Evidence for the effectiveness of treatments for subjects at ultrahigh risk (UHR) for developing psychosis remains inconclusive.

OBJECTIVE

A new cognitive behavioral intervention specifically targeted at cognitive biases (ie, Cognitive Behavioral Therapy [CBT] for UHR patients plus treatment as usual [TAU] called CBTuhr) is compared with TAU in a group of young help-seeking UHR subjects.

METHODS

A total of 201 patients were recruited at 4 sites and randomized. In most cases, CBTuhr was an add-on therapy because most people were seeking help for a comorbid disorder. The CBT was provided for 6 months, and the follow-up period was 18 months.

RESULTS

In the CBTuhr condition, 10 patients transitioned to psychosis compared with 22 in the TAU condition (χ(2) (1) = 5.575, P = .03). The number needed to treat (NNT) was 9 (95% confidence interval [CI]: 4.7-89.9). At 18-month follow-up the CBTuhr group was significantly more often remitted from an at-risk mental state, with a NNT of 7 (95% CI: 3.7-71.2). Intention-to-treat analysis, including 5 violations against exclusion criteria, showed a statistical tendency (χ(2) (1) = 3.338, P = .06).

CONCLUSIONS

Compared with TAU, this new CBT (focusing on normalization and awareness of cognitive biases) showed a favorable effect on the transition to psychosis and reduction of subclinical psychotic symptoms in subjects at UHR to develop psychosis.

Detection of people at risk of developing a first psychosis: comparison of two recruitment strategies

OBJECTIVE

Better recruitment strategies are needed to improve the identification of people at ultra-high risk of developing psychosis. This study explores the effectiveness of two recruitment strategies: a screening method in a consecutive help-seeking population entering secondary mental health services for non-psychotic problems vs. a population referred to the diagnostic center of an early-psychosis clinic.

METHOD

From February 2008 to February 2010, all general practitioner and self-referrals (aged 18-35 years) to the secondary mental healthcare service in The Hague and Zoetermeer were screened with the Prodromal Questionnaire; patients who scored above the cutoff of 18 and had a decline in social functioning were assessed using the Comprehensive Assessment of At-Risk Mental States (CAARMS). All referrals (aged 14-35 years) to the diagnostic center in Amsterdam were also assessed with the CAARMS.

RESULTS

The screening detected a three-fold higher prevalence of at-risk mental states: these subjects were older and more often female. manova showed significantly higher scores for the screened population on depression, social anxiety, distress with positive symptoms, and a higher rate of transition to psychosis within 12 months.

CONCLUSION

The screening method detects more patients with at-risk mental states than the referral method. The latter method is biased to young male patients in an earlier prodromal stage and a lower transition rate.

Ethnicity and baseline symptomatology in patients with an At Risk Mental State for psychosis

BACKGROUND

Ethnicity has been associated with different incidence rates and different symptom profiles in young patients with psychotic-like disorders. No studies so far have examined the effect of ethnicity on symptoms in people with an At Risk Mental State (ARMS).

METHOD

In this cross-sectional study, we analysed the relationship between ethnicity and baseline data on the severity of psychopathology scores in 201 help-seeking patients who met the ARMS criteria and agreed to participate in the Dutch Early Detection and Intervention (EDIE-NL) trial. Eighty-seven of these patients had a non-Dutch ethnicity. We explored the possible mediating role of ethnic identity.

RESULTS

Higher rates of negative symptoms, and of anhedonia in particular, were found in the ethnic minority group. This result could be attributed mainly to the Moroccan-Dutch and Turkish-Dutch subgroups, who also presented with more depression symptoms when the groups were examined separately. The ethnic minority group displayed a lower level of ethnic group identity compared to the immigrants of the International Comparative Study of Ethnocultural Youth (ICSEY). Ethnic identity was inversely related to symptoms in the Moroccan-Dutch patient group.

CONCLUSIONS

The prevalence of more severe negative symptoms and depression symptoms in ethnic minority groups deserves more attention, as the experience of attenuated positive symptoms when accompanied by negative symptoms or distress has proven to be predictive for transition to a first psychotic episode.

Cannabis use and age at onset of symptoms in subjects at clinical high risk for psychosis

OBJECTIVE

Numerous studies have found a robust association between cannabis use and the onset of psychosis. Nevertheless, the relationship between cannabis use and the onset of early (or, in retrospect, prodromal) symptoms of psychosis remains unclear. The study focused on investigating the relationship between cannabis use and early and high-risk symptoms in subjects at clinical high risk for psychosis.

METHOD

Prospective multicenter, naturalistic field study with an 18-month follow-up period in 245 help-seeking individuals clinically at high risk. The Composite International Diagnostic Interview was used to assess their cannabis use. Age at onset of high risk or certain early symptoms was assessed retrospectively with the Interview for the Retrospective Assessment of the Onset of Schizophrenia.

RESULTS

Younger age at onset of cannabis use or a cannabis use disorder was significantly related to younger age at onset of six symptoms (0.33 < r(s) < 0.83, 0.004 < P < 0.001). Onset of cannabis use preceded symptoms in most participants.

CONCLUSION

Our results provide support that cannabis use plays an important role in the development of psychosis in vulnerable individuals. Cannabis use in early adolescence should be discouraged.

Semantic fluency deficits and reduced grey matter before transition to psychosis: a voxelwise correlational analysis

Early identification of subjects with an increased risk of psychosis is necessary to develop interventions to delay or prevent disease onset. We recently reported that decreased semantic verbal fluency performance in ultra high risk (UHR) subjects predicts the development of psychosis (Becker et al., 2010). The present study investigated whether semantic and verbal fluency scores correlate with grey matter density in UHR subjects. Thirty-seven UHR subjects underwent structural MRI scanning and verbal fluency assessment after which they were followed up for 2 years. Using voxel-based morphometry, we investigated whether grey matter density correlated with verbal fluency scores in 10 UHR subjects who developed psychosis during follow-up and 27 UHR subjects who did not develop psychosis. In UHR subjects developing psychosis, lower semantic fluency scores correlated significantly with reduced grey matter density in the right superior and middle temporal gyrus, the right insula, and the left anterior cingulate cortex. This study shows that a correlation between semantic fluency performance and grey matter density in task-related areas can differentiate between UHR subjects who subsequently will develop psychosis and those who will not. Combining these two measures could improve psychosis prediction in UHR subjects.

Auditory ERP components before and after transition to a first psychotic episode

We investigated the course of Event Related Potentials (ERP) from prior to until shortly after a first psychotic episode in subjects at Ultra High Risk (UHR) for psychosis. N1, N2, N2b, P2 and P3 amplitudes were assessed using an auditory active oddball paradigm in 15 UHR subjects who made a transition to psychosis (UHR+T) at follow up, 23 subjects without a transition (UHR+NT) and 17 matched healthy controls at inclusion and again after approximately 18 months. Repeated-measures analyses revealed no significant time effects for any of the ERP components. However, an interaction effect was found for N1 amplitudes. Post-hoc analyses showed that N1 amplitudes were smaller at follow up compared to baseline only in UHR+T subjects. P3 amplitudes showed no further reduction after psychotic onset. These findings suggest that discernable ERP components behave differently during progression from the prodromal phase to the first psychotic episode. These findings may give insight in pathophysiological mechanisms underlying the genesis of psychosis.

Treating prolactinoma and psychosis: medication and cognitive behavioural therapy

The patient in this case report had two severe medical conditions that require oppositional treatment: prolactinoma and psychosis. A prolactinoma is a benign tumour of the pituitary gland that produces prolactin. Dopamine agonist medication is the first-line treatment in patients with prolactinoma. The psychotic symptoms started after a dosage increase of a dopamine D2-receptor agonist. Several antipsychotic medications were tried with and without the dopamine D2-receptor agonist, but severe command hallucinations remained. Cognitive behavioural therapy (CBT) was added which reduced the impact of the hallucinations to a great extent, indicating that CBT can have an additional positive effect in prolactinoma patients with psychosis that shows incomplete recovery after antipsychotic medication. Future research should be aimed at the severe and prolonged side effects of dopamine agonists in the treatment of prolactinoma patients with multiple risk factors for a psychotic decompensation.

Factor analysis of the scale of prodromal symptoms: differentiating between negative and depression symptoms

BACKGROUND

This study examines the ability of the Scale of Prodromal Symptoms (SOPS) to differentiate between negative and depression symptoms in a young help-seeking ultrahigh risk (UHR) group.

METHODS

SOPS data of 77 help-seeking patients at UHR for psychosis were analyzed with an exploratory factor analysis. The extracted Depression factor was validated with the Beck Depression Inventory (BDI). The extracted SOPS Negative symptoms factor was validated with the Negative symptoms subscale of the Positive and Negative Syndrome Scale (PANSS).

RESULTS

Four factors were extracted from the SOPS: a negative, depression, disorganized and positive factor. The Negative symptom factor consisted of three items (N1: social anhedonia and withdrawal, N3: decreased expression of emotion; N4: decreased experience of emotions and self), and could be validated with the PANSS Negative symptoms subscale. The Depression factor was also made up of three items (G2: dysphoric mood, G4: impaired tolerance to normal stress, and D4: personal hygiene/social attentiveness), and could be validated with the BDI.

CONCLUSIONS

Our results suggest that 3 items of the Negative symptoms subscale of the SOPS, 2 items of the General and 1 item of the Disorganization subscale differentiate validly between negative and depression symptoms in an UHR population.

Three-year course of clinical symptomatology in young people at ultra high risk for transition to psychosis

OBJECTIVE

The investigation into the course of ultra high risk (UHR) symptomatology of those patients who eventually do not meet the psychosis-threshold criteria within the 3-year timeframe of the study.

METHOD

The course of UHR symptoms, GAF score and employment status was investigated in 57 patients who did not make a transition to psychosis and who were examined within the Dutch Prediction of Psychosis Study in Amsterdam, the Netherlands.

RESULTS

At the 3-year follow-up, 75% of the patients who did not make a transition to psychosis had remitted from UHR status. With a Generalized Estimation Equation Model it was shown that this group recovered from positive (F = 52.7, P < 0.0001), negative (F = 24.3, P < 0.0001), disorganization (F = 14.4, P < 0.0001) and general symptoms (F = 25.0, P < 0.0001) within the timeframe of the study. In addition, the level of global functioning and likelihood of having a job and/or education significantly improved. The largest improvements occurred within the first year. UHR symptoms did not re-occur after improvement.

CONCLUSION

With the current UHR criteria, a large percentage of the included subjects appear to have transitory complaints and dysfunctioning. A refinement of the UHR criteria may diminish the chance of including 'false positives' in future UHR studies.

Environmental factors and social adjustment as predictors of a first psychosis in subjects at ultra high risk

BACKGROUND

The onset of schizophrenia is associated with genetic, symptomatic, social and environmental risk factors. The aim of the present study was to determine which environmental factors may contribute to a prediction of a first psychotic episode in subjects at Ultra High Risk (UHR) for developing psychosis.

METHOD

We included 72 UHR subjects and followed them over a period of 36 months, of whom nineteen (26.4%) made a transition to psychosis. We applied survival analyses to determine associations between a transition to psychosis and environmental factors and social adjustment. To determine which items are the best predictors of transition to a first psychotic episode, Cox Regression analyses were applied.

RESULTS

Urbanicity, receiving state benefits and poor premorbid adjustment (PMA) significantly influenced the transition to psychosis. Urbanicity (Wald=10.096, p=.001, HR=30.97), social-sexual aspects (Wald=8.795, p=.003, HR=1.91) and social-personal adjustment (Wald=10.794, p=.001, HR=4.26) appeared to be predictors for developing psychosis in our UHR group.

CONCLUSIONS

Environmental characteristics and social adjustment are predictive of transition to a psychosis in subjects at UHR. These characteristics should be implemented in a model for prediction of psychosis. Such a model would be more specific than current models and may lead to patient-specific preventive interventions.

Disability in people clinically at high risk of psychosis

BACKGROUND

Decline in social functioning occurs in individuals who later develop psychosis.

AIMS

To investigate whether baseline differences in disability are present in those who do and those who do not make a transition to psychosis in a group clinically at high risk and whether disability is a risk factor for transition.

METHOD

Prospective multicentre, naturalistic field study with an 18-month follow-up period on 245 help-seeking individuals clinically at high risk. Disability was assessed with the Disability Assessment Schedule of the World Health Organization (WHODAS-II).

RESULTS

At baseline, the transition group displayed significantly greater difficulties in making new friends (z = -3.40, P = 0.001), maintaining a friendship (z =-3.00, P = 0.003), dealing with people they do not know (z =-2.28, P = 0.023) and joining community activities (z =-2.0, P = 0.05) compared with the non-transition group. In Cox regression, difficulties in getting along with people significantly contributed to the prediction of transition to psychosis in our sample (β = 0.569, s.e. = 0.184, Wald = 9.548, P = 0.002, hazard ratio (HR) = 1.767, 95% CI 1.238-2.550).

CONCLUSIONS

Certain domains of social disability might contribute to the prediction of psychosis in a sample clinically at high risk.

Neurocognitive functioning before and after the first psychotic episode: does psychosis result in cognitive deterioration?

BACKGROUND

Cognitive impairment is considered to be a core characteristic of schizophrenia. The relationship between psychosis and cognitive deterioration, however, remains unclear. This longitudinal study investigated the neuropsychological functioning of patients before and after their first psychotic episode. Cognitive functioning of participants who later developed a psychosis was compared to that of people at ultra-high risk (UHR) for psychosis who did not develop psychosis at follow-up and healthy controls.MethodParticipants were 41 persons at UHR for psychosis (the UHR group), of whom 17 developed psychosis between the first and second assessment. Seventeen healthy controls were included in the study. Cognitive performance was assessed at intake (T0) and again after 18 months (T1). The areas of cognitive functioning assessed include verbal memory and learning, visuospatial working memory, executive function, sustained attention and motor speed.

RESULTS

The transition group did not perform significantly worse at the second assessment than at the first on any of the outcome measures. The UHR group performed better on a verbal learning and memory test at T1 compared to T0. At T0, the control group scored significantly better than the UHR group and the transition group on the verbal learning and memory test and the verbal fluency test.

CONCLUSIONS

The results indicate that no cognitive deterioration occurs during the first psychotic episode. Problems in verbal memory may be present before the first episode of psychosis.

Reduced parietal P300 amplitude is associated with an increased risk for a first psychotic episode

BACKGROUND

P300 abnormalities indicate changes in information processing and are one of the most reliable biological markers of schizophrenia. We sought to investigate whether abnormalities in P300 (P3) or other event-related potentials are also present in subjects at ultra high risk (UHR) for developing psychosis and whether they are helpful in predicting transition to psychosis.

METHODS

The N1, N2, N2b, P2, and P3 amplitudes were assessed in 61 UHR subjects, of whom 18 subjects (30%) made a transition to psychosis over a 3-year follow-up period (UHR + T: age 20.4 years) and 43 (70%) did not (UHR + NT: age 19.3 years), and 28 age- and intelligence-matched healthy control subjects (age 20.0 years). Psychopathology was also assessed.

RESULTS

The UHR + T subjects showed smaller parietal P3 amplitudes, compared with control subjects and UHR + NT subjects. Moreover, the N2b was higher in control subjects compared with both UHR groups. We found no differences in N1 or P2 components between the groups, and our UHR subjects did not exhibit bilateral P3 asymmetry. Reduced P3 amplitudes were the best predictor for subsequent psychosis in the UHR group. The P3 reduction was related to increased social anhedonia and withdrawal and a lower global assessment of social functioning and social personal adjustment.

CONCLUSIONS

The UHR + T subjects showed reduced parietal P3 amplitudes. In addition, a reduced P3 amplitude was the best predictor for subsequent psychosis. If replicated, these findings might contribute to a more accurate prediction of a first psychotic episode. Furthermore, reduced social functioning might be related to information processing deficits in UHR subjects.

White-matter markers for psychosis in a prospective ultra-high-risk cohort

BACKGROUND

Subjects at 'ultra high risk' (UHR) for developing psychosis have differences in white matter (WM) compared with healthy controls. WM integrity has not yet been investigated in UHR subjects in relation to the development of subsequent psychosis. Hence, we investigated a prospective cohort of UHR subjects comparing whole brain fractional anisotropy (FA) of those later developing psychosis (UHR-P) to those who did not (UHR-NP).

METHOD

We recruited 37 subjects fulfilling UHR criteria and 10 healthy controls. Baseline 3 Tesla magnetic resonance imaging (MRI) scans and Positive and Negative Syndrome Scale (PANSS) ratings were obtained. UHR subjects were assessed at 9, 18 and 24 months for development of frank psychosis. We compared baseline FA of UHR-P to controls and UHR-NP subjects. Furthermore, we related clinical data to MRI outcome in the patient population.

RESULTS

Of the 37 UHR subjects, 10 had transition to psychosis. UHR-P subjects showed significantly lower FA values than control subjects in medial frontal lobes bilaterally. UHR-P subjects had lower FA values than UHR-NP subjects, lateral to the right putamen and in the left superior temporal lobe. UHR-P subjects showed higher FA values, compared with UHR-NP, in the left medial temporal lobe. In UHR-P, positive PANSS negatively correlated to FA in the left middle temporal lobe. In the total UHR group positive PANSS negatively correlated to FA in the right superior temporal lobe.

CONCLUSIONS

UHR subjects who later develop psychosis have differences in WM integrity, compared with UHR subjects who do not develop psychosis and to healthy controls, in brain areas associated with schizophrenia.

Increased saccadic rate during smooth pursuit eye movements in patients at Ultra High Risk for developing a psychosis

Abnormalities in eye tracking are consistently observed in schizophrenia patients and their relatives and have been proposed as an endophenotype of the disease. The aim of this study was to investigate the performance of patients at Ultra High Risk (UHR) for developing psychosis on a task of smooth pursuit eye movement (SPEM). Forty-six UHR patients and twenty-eight age and education matched controls were assessed with a task of SPEM and psychiatric questionnaires. Our results showed that both the corrective and non-corrective saccadic rates during pursuit were higher in the UHR group. There were however no differences in smooth pursuit gain between the two groups. The saccadic rate was related to positive UHR symptoms. Our findings indicate that abnormalities in SPEM are already present in UHR patients, prior to a first psychotic episode. These abnormalities occur only in the saccadic system.

Reduced context effects on retrieval in first-episode schizophrenia

Background

A recent modeling study by the authors predicted that contextual information is poorly integrated into episodic representations in schizophrenia, and that this is a main cause of the retrieval deficits seen in schizophrenia.

Methodology/Principal Findings

We have tested this prediction in patients with first-episode schizophrenia and matched controls. The benefit from contextual cues in retrieval was strongly reduced in patients. On the other hand, retrieval based on item cues was spared.

Conclusions/Significance

These results suggest that reduced integration of context information into episodic representations is a core deficit in schizophrenia and one of the main causes of episodic memory impairment.