Neurocognitive predictors of functional outcome two to 13 years after identification as ultra-high risk for psychosis

Background and aim

Little is known about the relationship between neurocognitive performance and functional outcome before the onset of frank psychosis. This longitudinal study aimed to investigate neurocognitive predictors of poor functional outcome in a group identified as ultra-high risk (UHR) for psychosis between two and 13 years prior.

Method

Individuals (N = 230) identified as UHR for psychosis at the PACE Clinic in Melbourne completed assessment of psychopathology, functioning and neurocognition at baseline and follow-up. The mean length of follow-up was 7.26 years (SD 3.05).

Results

Forty-one individuals with the poorest functional outcome were identified. Only 48.8% of this group had transitioned to psychosis. Poor functional outcome was associated with reduced performance at baseline in the specific neurocognitive domains of verbal learning and memory, processing speed and attention, and verbal fluency, but not global cognitive impairment. Reduced performance on a verbal story recall task, in combination with higher negative symptoms at baseline, was the best predictor of later poor outcome. Baseline positive psychotic symptoms and GAF scores were not associated with later poor outcome.

Discussion

To date, this is the longest follow-up study of an UHR sample. Poor functional outcome was associated with specific neurocognitive decrements, regardless of transition to psychosis. The detection of individuals with poor functioning at follow-up, against a background of previously identified risk factors for psychotic disorder, may yield a valid group in which to study biomarkers and treatment of schizophrenia.     

Hippocampal subdivision and amygdalar volumes in patients in an at-risk mental state for schizophrenia

Background

Accumulating evidence from postmortem and magnetic resonance imaging (MRI) studies suggests that abnormalities of medial temporal lobe structures are critically involved in the pathogenesis of schizophrenia. It is still unclear, however, whether certain abnormalities are already present in individuals at ultra high-risk (UHR) for transition into psychosis. Recent studies involving patients at UHR showed contradictory results for hippocampal volume, and only 1 study reported that amygdalar volume was unchanged between healthy patients and those at UHR. Furthermore, no subregions of the hippocampus have been investigated in people at UHR.

Methods

We recruited 29 UHR patients, 23 first-episode patients and 29 age-and sex-matched healthy controls. We measured hippocampal and amygdalar volumes from MRI scans by use of BRAINS2 to manually trace the regions of interest. The hippocampi were divided in 2 regions: head and corpus/tail.

Results

Patients at UHR had significantly smaller volumes of the hippocampus corpus and tail bilaterally, but not of the head, compared with healthy controls. Group differences for the right hippocampus corpus and tail volume remained significant after we controlled for whole brain volume and other covariates. We found that UHR patients who later developed psychosis had smaller right hippocampus corpus and tail volumes than did those who did not develop psychosis. First-episode patients had significantly smaller left amygdalar volumes than did healthy individuals or those at UHR.

Limitations

Our study had a small sample size, and we were unable to control for the effects of medication.

Conclusion

Our findings suggest that parts of the hippocampal–amygdalar complex are involved in the pathogenesis of schizophrenia. Reduction of hippocampus corpus and tail volumes may be indicative of the prodromal phase of schizophrenia and represent risk factors for transition into psychosis. Further investigations are needed to determine whether structural changes of the left amygdala play a role during transition from the prodromal phase to the first manifest episode of schizophrenia.     

A randomized controlled trial of cognitive behavioral therapy for individuals at clinical high risk of psychosis

Background

Symptomatic and functional outcomes in schizophrenia are associated with the duration of untreated psychosis. However, no candidate biomarkers have been adopted in clinical settings. Multichannel near-infrared spectroscopy (NIRS), which can easily and noninvasively measure hemodynamics over the prefrontal cortex, is a candidate instrument for clinical use.

Aims

We intended to explore prefrontal dysfunction among individuals at different clinical stages, including ultra-high-risk (UHR), first-episode psychosis (FEP), and chronic schizophrenia (ChSZ), compared to healthy subjects.

Method

Twenty-two UHR subjects, 27 patients with FEP, 38 patients with ChSZ, and 30 healthy subjects participated. We measured hemodynamic changes during a block-designed letter fluency task using multichannel NIRS instruments.

Results

We found that the activations of the bilateral ventrolateral prefrontal cortex, and the fronto-polar and anterior parts of the temporal cortical regions in the UHR group were lower than those of the controls, but similar to those of the FEP and ChSZ groups. However, the activations in the bilateral dorsolateral prefrontal cortex regions decrease with advancing clinical stage.

Conclusions

To the best of our knowledge, this is the first study directly comparing differences in hemodynamic changes with respect to the 3 clinical stages of psychosis. Furthermore, this study also demonstrates different patterns of impairment according to the progression of clinical stages using NIRS instruments. NIRS measurements for UHR and FEP individuals may be candidate biomarkers for the early detection of the clinical stages of psychosis.     

Prediction of conversion to psychosis: review and future directions

This article reviews recent findings on predictors of conversion to psychosis among youth deemed at ultra high risk (UHR) based on the presence of subpsychotic-intensity symptoms or genetic risk for psychosis and a recent decline in functioning. Although transition rates differ between studies, the most well powered studies have observed rates of conversion to full psychosis in the 30-40% range over 2-3 years of follow-up. Across studies, severity of subthreshold positive symptoms, poorer social functioning, and genetic risk for schizophrenia appear to be consistent predictors of conversion to psychosis, with algorithms combining these indicators achieving positive predictive power > 80%. Nevertheless, a substantial fraction of UHR cases do not convert to psychosis. Recent work indicates that UHR cases who present with lower levels of negative symptoms and higher levels of social functioning are more likely to recover symptomatically and no longer meet criteria for an at-risk mental state. In general, it appears that about 1/3 of UHR cases convert to psychosis, about 1/3 do not convert but remain symptomatic and functionally impaired, and about 1/3 recover symptomatically and functionally. Continued efforts to detect early risk for psychosis are critical for informing early intervention and provide increasing promise of delaying or even preventing the onset of psychosis.     

Alterations in White Matter Evident Before the Onset of Psychosis

Background

Psychotic disorders are associated with widespread reductions in white matter (WM) integrity. However, the stage at which these abnormalities first appear and whether they are correlates of psychotic illness, as opposed to an increased vulnerability to psychosis, is unclear. We addressed these issues by using diffusion tensor imaging (DTI) to study subjects at ultra high risk (UHR) of psychosis before and after the onset of illness.

Methods

Thirty-two individuals at UHR for psychosis, 32 controls, and 15 patients with first-episode schizophrenia were studied using DTI. The UHR subjects and controls were re-scanned after 28 months. During this period, 8 UHR subjects had developed schizophrenia. Between-group differences in fractional anisotropy (FA) and diffusivity were evaluated cross sectionally and longitudinally using a nonparametric voxel-based analysis.

Results

At baseline, WM DTI properties were significantly different between the 3 groups (P < .001). Relative to controls, first-episode patients showed widespread reductions in FA and increases in diffusivity. DTI indices in the UHR group were intermediate relative to those in the other 2 groups. Longitudinal analysis revealed a significant group by time interaction in the left frontal WM (P < .001). In this region, there was a progressive reduction in FA in UHR subjects who developed psychosis that was not evident in UHR subjects who did not make a transition.

Conclusions

People at UHR for psychosis show alterations in WM qualitatively similar to, but less severe than, those in patients with schizophrenia. The onset of schizophrenia may be associated with a progressive reduction in the integrity of the frontal WM.     

Neurocognitive performance in subjects at ultrahigh risk for schizophrenia: a comparison with first-episode schizophrenia

Objective

The aim of the present study was to explore the neurocognitive performance of patients at ultrahigh risk (UHR) compared with patients with first-episode (FE) schizophrenia and healthy control (HC) subjects.

Method

Twenty-seven subjects at UHR for schizophrenia, 25 patients in their FE of schizophrenia, and 33 HCs were included. All participants completed a neurocognitive battery, including tests of general intelligence, attention and working memory, executive function, and verbal and visual memory.

Results

Of the 3 groups, the FE subjects performed poorest at all neurocognitive tests, encompassing the broad range of impairments. The UHR subjects had a similar pattern of neuropsychological dysfunction but less severe than that of FE patients. The UHR subjects were particularly impaired on measures of attention and working memory, executive function, and verbal memory compared with the HCs.

Conclusion

These findings are consistent with the view that the neurocognitive impairments of schizophrenia are neurodevelopmental in nature and, although less severe, those impairments are mostly in place before the onset of the first frank psychotic episode. Neurocognitive impairments may play an important role in the pathogenesis of early psychosis and could help to clarify individuals at UHR for schizophrenia.     

Depressive Symptoms and Brain Metabolite Alterations in Subjects at Ultra-high Risk for Psychosis: A Preliminary Study

Objective

Recent neuroimaging studies have suggested that brain changes occur in subjects at ultra-high risk (UHR) for psychosis while experiencing prodromal symptoms, among which depression may increase the risk of developing a psychotic disorder. The goal of this study is to examine brain metabolite levels in the anterior cingulate cortex, the left dorsolateral prefrontal cortex and the left thalamus in subjects at UHR for psychosis and to compare brain metabolite levels between the UHR subjects with comorbid major depressive disorder and healthy controls.

Methods

Proton magnetic resonance spectroscopy was used to examine brain metabolite levels. Twenty UHR subjects and 20 age- and intelligence quotient (IQ)-matched healthy controls were included in this study.

Results

Overall, no significant differences were observed in any metabolite between the UHR and healthy control group. However, UHR subjects with major depressive disorder showed significantly higher myo-inositol (Ins) levels in the left thalamus, compared to the healthy control.

Conclusion

Our results demonstrate that increased thalamic Ins level is associated with prodromal depressive symptoms. Further longitudinal follow-up studies with larger UHR sample sizes are required to investigate the function of Ins concentrations as a biomarker of vulnerability to psychosis.     

Reduced prepulse inhibition in adolescents at risk for psychosis: a 2-year follow-up study

Background

Reduced prepulse inhibition (PPI) of the auditory startle reflex is a hallmark feature of attention-processing deficits in patients with schizophrenia and other psychotic disorders. Recent evidence suggests that these deficits may also be present before the onset of psychosis in individuals at ultra-high risk (UHR) and become progressively worse as psychosis develops. We conducted a longitudinal follow-up study to observe the development of PPI over time in UHR adolescents and healthy controls.

Methods

Two-year follow-up data of PPI measures were compared between UHR adolescents and a matched control group of typically developing individuals.

Results

We included 42 UHR adolescents and 32 matched controls in our study. Compared with controls, UHR individuals showed reduced PPI at both assessments. Clinical improvement in UHR individuals was associated with an increase in PPI parameters.

Limitations

A developmental increase in startle magnitude partially confined the interpretation of the association between clinical status and PPI. Furthermore, post hoc analyses for UHR individuals who became psychotic between assessments had limited power owing to a low transition rate (14%).

Conclusion

Deficits in PPI are present before the onset of psychosis and represent a stable vulnerability marker over time in UHR individuals. The magnitude of this marker may partially depend on the severity of clinical symptoms.     

Fluvoxamine may prevent onset of psychosis: a case report of a patient at ultra-high risk of psychotic disorder

Background

There is emerging evidence that antidepressants may be effective in preventing patients with non-specific and psychotic-like prodromal symptoms, defined as patients at ultra-high risk (UHR) of psychotic disorder, from transitioning to psychosis. However, the mechanism of such an effect is still unknown.

Methods

We report the case of a 19-year-old Japanese man determined to be at UHR of psychotic disorder in whom fluvoxamine (one of the antidepressants with sigma-1 receptor agonism) showed preventive effects on psychotic-like prodromal symptoms.

Results

Our patient's depressive symptoms were reduced and maintained below remission as a result of treatment with 100 mg/day of fluvoxamine. In addition, it is likely that an additional dose of fluvoxamine (50 mg/day) improved his psychotic-like prodromal symptoms directly, independent of its antidepressive effects.

Conclusion

Fluvoxamine, a sigma-1 receptor agonist, may be effective in preventing patients at UHR of psychotic disorder from onset of psychosis via its neuroprotective/neurotropic actions, independent of its antidepressive effects.     

Pituitary volume predicts future transition to psychosis in individuals at ultra-high risk of developing psychosis.

BACKGROUND: We examined pituitary volume before the onset of psychosis in subjects who were at ultra-high risk (UHR) for developing psychosis. METHODS: Pituitary volume was measured on 1.5-mm, coronal, 1.5-T magnetic resonance images in 94 UHR subjects recruited from admissions to the Personal Assessment and Crisis Evaluation Clinic in Melbourne, Australia and in 49 healthy control subjects. The UHR subjects were scanned at baseline and were followed clinically for a minimum of 1 year to detect transition to psychosis. RESULTS: Within the UHR group, a larger baseline pituitary volume was a significant predictor of future transition to psychosis. The UHR subjects who later went on to develop psychosis (UHR-P, n = 31) had a significantly larger (+12%; p = .001) baseline pituitary volume compared with UHR subjects who did not go on to develop psychosis (UHR-NP, n = 63). The survival analysis conducted by Cox regression showed that the risk of developing psychosis during the follow-up increased by 20% for every 10% increase in baseline pituitary volume (p = .002). Baseline pituitary volume of the UHR-NP subjects was smaller not only compared with UHR-P (as described above) but also compared with control subjects (-6%; p = .032). CONCLUSIONS: The phase before the onset of psychosis is associated with a larger pituitary volume, suggesting activation of the HPA axis.     

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. Key words: cognitive behavioral therapy, ultrahigh risk, cognitive biases, prevention, psychosis, schizophrenia     

White matter connectivity and psychosis in ultra-high-risk subjects: A diffusion tensor fiber tracking study

This study assessed with diffusion tensor imaging (DTI) whether ultra-high-risk subjects who later develop a psychotic disorder (UHR-P) show abnormalities in association white matter fiber tracts as compared to UHR subjects who do not convert to psychosis (UHR-NP) and healthy controls. Participants comprised 17 male UHR subjects and 10 male healthy controls, who received baseline DTI scans before clinical follow-up. The uncinate and arcuate fasciculi, anterior and dorsal cingulate, and subdivisions of the corpus callosum were calculated and visualized, and tract-specific measurements were performed. At 24-month follow-up seven UHR subjects had developed a first psychotic episode. Fractional anisotropy in baseline DTI scans, including left-right asymmetry measures, did not differ between the groups. Thus, DTI measures of these association white matter tracts were not biological markers of psychosis in our UHR sample. Abnormalities of these fiber tracts may develop around or after onset of psychosis. However, further DTI studies in UHR subjects are needed in larger samples.     

Temperament and character in individuals at ultra-high risk for psychosis and with first-episode schizophrenia: Associations with psychopathology,psychosocial functioning,and aspects of psychological health

Objective

The psychobiological model of temperament and character indicates that personality traits are heritable and, during development, constantly influence one’s susceptibility to schizophrenia. Our objective was to evaluate temperament and character in subjects at ultra-high risk (UHR) for psychosis and individuals with first-episode schizophrenia.

Methods

UHR for psychosis subjects (n = 50), first-episode schizophrenia patients (n = 33), and normal controls (n = 120) were compared on temperament and character dimensions, and correlation analysis of each personality dimension with psychopathologies, global and social functioning, and self-esteem. General and social self-efficacy reports were conducted. UHR subjects were followed-up for 24 months and the baseline personality dimensions were compared between the converted and non-converted groups.

Results

Both clinical groups showed abnormal personality traits in terms of temperament (higher harm avoidance, lower reward dependence and persistence) and character (lower self-directedness and cooperativeness). Psychosocial functioning and psychological health components were found to be correlated with some personality dimensions. The conversion rate of overt psychotic disorder was 25.0% at the 24-month follow-up. Baseline cooperativeness dimension was a significant predictive dimension for conversion into overt psychosis in the UHR group during the follow-up period.

Conclusion

Patients with first episode schizophrenia have a pervasively altered personality profile from normal controls. More importantly, this altered personality profile already emerged in putative prodromal, UHR individuals. The present findings indicate that certain personality traits can play a protective or vulnerable role in developing schizophrenia.     

Auditory gamma oscillations predict global symptomatic outcome in the early stages of psychosis: A longitudinal investigation

Objectives

The gamma-band auditory steady-state response (ASSR) is thought to reflect the function of parvalbumin-positive γ-aminobutyric acid (GABA)-ergic interneurons and may be a candidate biomarker in early psychosis. Although previous cross-sectional studies have shown that gamma-band ASSR is reduced in early psychosis, whether reduced gamma-band ASSR could be a predictor of the long-term prognosis remains unknown.

Progressive structural brain changes during development of psychosis

Background:

Ultra-high risk (UHR) for psychosis has been associated with widespread structural brain changes in young adults. The onset of these changes and their subsequent progression over time are not well understood.

Methods:

Rate of brain change over time was investigated in 43 adolescents at UHR for psychosis compared with 30 healthy controls. Brain volumes (total brain, gray matter, white matter [WM], cerebellum, and ventricles), cortical thickness, and voxel-based morphometry were measured at baseline and at follow-up (2 y after baseline) and compared between UHR individuals and controls. Post hoc analyses were done for UHR individuals who became psychotic (N = 8) and those who did not (N = 35).

Results:

UHR individuals showed a smaller increase in cerebral WM over time than controls and more cortical thinning in the left middle temporal gyrus. Post hoc, a more pronounced decrease over time in total brain and WM volume was found for UHR individuals who became psychotic relative to controls and a greater decrease in total brain volume than individuals who were not psychotic. Furthermore, UHR individuals with subsequent psychosis displayed more thinning than controls in widespread areas in the left anterior cingulate, precuneus, and temporo-parieto-occipital area. Volume loss in the individuals who developed psychosis could not be attributed to medication use.

Conclusion:

The development of psychosis during adolescence is associated with progressive structural brain changes around the time of onset. These changes cannot be attributed to (antipsychotic) medication use and are therefore likely to reflect a pathophysiological process related to clinical manifestation of psychosis.     

Rates and predictors of 18-months remission in an epidemiological cohort of 661 patients with first-episode psychosis

Objectives

Most first episode psychosis (FEP) outcome studies are based on patient samples enrolled through an informed consent procedure, which may induce important biases. Our aim was to study the 18-month outcome of FEP in an epidemiological sample of patients treated at the Early Psychosis Prevention and Intervention Centre (EPPIC).

Methods

The files of 661 FEP patients treated for up to 18 months between 1998 and 2000 were assessed. Symptomatic remission was defined as receiving a score ≤3 on the Clinical Global Impressions (CGI) scales, and functional remission as concurrent fulfillment of occupation/employment and independent living. Predictors were analyzed using stepwise logistic regression models.

Results

At endpoint, 63% of FEP patients had reached symptomatic remission and 44% functional remission. Duration of untreated psychosis, baseline symptom intensity, time in service and decrease or remission of substance use, predicted both symptomatic and functional outcome. A history of suicide attempt or non-adherence to medication was linked to lower likelihood to reach symptomatic remission while pre-morbid GAF and employment at baseline were linked to functional outcome.

Conclusions

The development of early intervention strategies should be pursued, in order both to provide treatment before symptoms reach a high intensity and to maintain social integration. Specific strategies need to promote engagement, facilitate adherence to medication and to create a framework where key issues such as substance abuse co-morbidity can be addressed.

     

Patterns of referral in first-episode schizophrenia and ultra high-risk individuals: results from an early intervention program in Italy

Purpose

This study set out to investigate the patterns of referral in a sample (n = 206) of patients having first-time access to an Italian comprehensive program that targets the early detection of and early intervention on subjects at the onset of psychosis. The primary goal of the study was to investigate the duration of untreated illness (DUI) and/or the duration of untreated psychosis (DUP) in the sample since the implementation of the program.

Method

Data on pathways of referrals prospectively collected over a 11-year period, from 1999 to 2010; data referred to patients from a defined catchment area, and who met ICD-10 criteria for a first episode of a psychotic disorder (FEP) or were classified to be at ultra-high risk of psychosis (UHR) according to the criteria developed by the Personal Assessment and Crisis Evaluation (PACE) Clinic in Melbourne. Changes over time in the DUI and DUP were investigated in the sample.

Results

Referrals increased over time, with 20 subjects enrolled per year in the latter years of the study. A large majority of patients contacted a public or private mental health care professional along their pathway to treatment, occurring more often in FEP than in UHR patients. FEP patients who had contact with a non-psychiatric health care professional had a longer DUP. Over time, DUP and DUI did not change in FEP patients, but DUI increased, on average, in UHR patients.

Conclusions

The establishment of an EIP in a large metropolitan area led to an increase of referrals from people and agencies that are not directly involved in the mental health care system; over time, there was an increase in the number of patients with longer DUI and DUP than those who normally apply for psychiatric services.     

Adolescents at ultra-high risk of psychosis in Italian neuropsychiatry services: prevalence,psychopathology and transition rate

Studies in adolescents on ultra-high risk (UHR) and basic symptoms (BS) criteria for psychosis prediction are scarce. In Italy, early interventions in psychosis are less widespread than in other European countries. In the present study, we (1) assessed the clinical relevance of a UHR diagnosis [according to the comprehensive assessment of at-risk mental states (CAARMS) criteria] to promote the implementation of specific services for UHR adolescents into the Italian health care system; (2) described severity of positive, negative, general, and basic symptoms in UHR adolescents compared to adolescents with first-episode psychosis (FEP) and non-UHR adolescents (i.e., individuals who did not meet CAARMS criteria for UHR or FEP); and (3) investigated the predictive validity of UHR criteria in relation to BS criteria. Seventy-nine adolescents (aged 13–18 years) were assessed with the CAARMS, the positive and negative syndrome scale (PANSS), and the schizophrenia proneness instrument, child and youth version (SPI-CY). Both UHR (n = 25) and FEP (n = 11) had significantly higher PANSS subscale scores compared to non-UHR (n = 43). UHR had significantly lower PANSS-positive symptom scores than FEP, but similar global functioning and PANSS-negative symptoms and general psychopathology scores. Compared to non-UHR, both FEP and UHR had more severe thought and perception BS disturbances, and significantly more often met BS criteria. After 12 months, 2 of 20 (10%) UHR had transitioned to psychosis. They also met both BS criteria. Given the uncertain outcome of UHR adolescents, future research is needed to determine whether the combined assessment of BS with UHR symptoms can improve the accuracy of psychosis prediction in adolescence.     

Sexual Trauma Increases the Risk of Developing Psychosis in an Ultra High-Risk “Prodromal” Population

Studies indicate a high prevalence of childhood trauma in patient cohorts with established psychotic disorder and in those at risk of developing psychosis. A causal link between childhood trauma and development of psychosis has been proposed. We aimed to examine the association between experience of childhood trauma and the development of a psychotic disorder in a large “Ultra High Risk” (UHR) for psychosis cohort. The data were collected as part of a longitudinal cohort study of all UHR patients recruited to research studies at the Personal Assessment and Clinical Evaluation clinic between 1993 and 2006. Baseline data were collected at recruitment to these studies. The participants completed a comprehensive follow-up assessment battery (mean time to follow-up 7.5 years, range 2.4–14.9 years), which included the Childhood Trauma Questionnaire (CTQ), a self-report questionnaire that assesses experience of childhood trauma. The outcome of interest was transition to a psychotic disorder during the follow-up period. Data were available on 233 individuals. Total CTQ trauma score was not associated with transition to psychosis. Of the individual trauma types, only sexual abuse was associated with transition to psychosis (P = .02). The association remained when adjusting for potential confounding factors. Those with high sexual abuse scores were estimated to have a transition risk 2–4 times that of those with low scores. The findings suggest that sexual trauma may be an important contributing factor in development of psychosis for some individuals.Key words: trauma, psychosis, ultra high risk     

Functional Outcome in People at High Risk for Psychosis Predicted by Thalamic Glutamate Levels and Prefronto-Striatal Activation

Little is known about the neurobiological factors that determine functional outcome in people at high risk for psychosis. We use multimodal neuroimaging to investigate whether cortical responses during a cognitive task and thalamic glutamate levels were associated with subsequent functional outcome. Sixty subjects participated: 27 healthy controls (CTRL) and 33 at ultrahigh risk (UHR) for psychosis. At baseline, cortical responses during a verbal fluency task were measured using functional Magnetic Resonance Imaging (fMRI) and proton Magnetic Resonance Spectroscopy (1H-MRS) was used to measure thalamic glutamate levels. The UHR subjects were then followed clinically for a mean duration of 18 months, and subdivided into “good” and “poor” functional outcome subgroups according to their Global Assessment of Function score at follow-up. UHR subjects with a poor functional outcome showed greater cortical and subcortical activation than UHR subjects with a good functional outcome. They also had lower levels of thalamic glutamate and showed a negative relationship between thalamic glutamate levels and prefrontal-striatal activation that was not present in the good functional outcome or control groups. In people at high risk for psychosis, their subsequent level of functioning may depend on the extent to which neurophysiological and neurochemical function is perturbed when they first present to clinical services.Key words: psychosis, ultra-high risk, functional outcomes, functional MRI, spectroscopy, glutamate