Don Linszen

Common variants conferring risk of schizophrenia

Schizophrenia is a complex disorder, caused by both genetic and environmental factors and their interactions. Research on pathogenesis has traditionally focused on neurotransmitter systems in the brain, particularly those involving dopamine. Schizophrenia has been considered a separate disease for over a century, but in the absence of clear biological markers, diagnosis has historically been based on signs and symptoms. A fundamental message emerging from genome-wide association studies of copy number variations (CNVs) associated with the disease is that its genetic basis does not necessarily conform to classical nosological disease boundaries. Certain CNVs confer not only high relative risk of schizophrenia but also of other psychiatric disorders. The structural variations associated with schizophrenia can involve several genes and the phenotypic syndromes, or the ‘genomic disorders’, have not yet been characterized. Single nucleotide polymorphism (SNP)-based genome-wide association studies with the potential to implicate individual genes in complex diseases may reveal underlying biological pathways. Here we combined SNP data from several large genome-wide scans and followed up the most significant association signals. We found significant association with several markers spanning the major histocompatibility complex (MHC) region on chromosome 6p21.3-22.1, a marker located upstream of the neurogranin gene (NRGN) on 11q24.2 and a marker in intron four of transcription factor 4 (TCF4) on 18q21.2. Our findings implicating the MHC region are consistent with an immune component to schizophrenia risk, whereas the association with NRGN and TCF4 points to perturbation of pathways involved in brain development, memory and cognition.

Prediction of Psychosis in Adolescents and Young Adults at High Risk: Results From the Prospective European Prediction of Psychosis Study

CONTEXT Indicated prevention is currently regarded as the most promising strategy to attenuate, delay, or even avert psychosis. Existing criteria need improvement in terms of specificity and individual risk assessment to allow for better targeted and earlier interventions. OBJECTIVE To develop a differential predictive clinical model of transition to first-episode psychosis. DESIGN Prospective multicenter, naturalistic field study with a total follow-up time of 18 months. SETTING Six early-detection outpatient centers in Germany, Finland, the Netherlands, and England. PARTICIPANTS Two hundred forty-five help-seeking patients in a putatively prodromal state of psychosis according to either ultra-high-risk (UHR) criteria or the basic symptom-based criterion cognitive disturbances (COGDIS). MAIN OUTCOME MEASURE Incidence of transition to psychosis. RESULTS At 18-month follow-up, the incidence rate for transition to psychosis was 19%. Combining UHR and COGDIS yielded the best sensitivity. A prediction model was developed and included positive symptoms, bizarre thinking, sleep disturbances, a schizotypal disorder, level of functioning in the past year, and years of education. With a positive likelihood ratio of 19.9, an area under the curve of 80.8%, and a positive predictive value of 83.3%, diagnostic accuracy was excellent. A 4-level prognostic index further classifying the general risk of the whole sample predicted instantaneous incidence rates of up to 85% and allowed for an estimation of time to transition. CONCLUSIONS The prediction model identified an increased risk of psychosis with appropriate prognostic accuracy in our sample. A 2-step risk assessment is proposed, with UHR and cognitive disturbance criteria serving as first-step criteria for general risk and the prognostic index as a second-step tool for further risk classification of each patient. This strategy will allow clinicians to target preventive measures and will support efforts to unveil the biological and environmental mechanisms underlying progression to psychosis.

Preventing a first episode of psychosis: Meta-analysis of randomized controlled prevention trials of 12 month and longer-term follow-ups

Over the last decade many studies were conducted to assess the feasibility of early detection of people at risk of developing psychosis and intervention to prevent or delay a first psychotic episode. Most of these studies were small and underpowered. A meta-analysis can demonstrate the effectiveness of the efforts to prevent or postpone a first episode of psychosis. A search conducted according the PRISMA guideline identified 10 studies reporting 12-month follow-up data on transition to psychosis, and 5 studies with follow-ups varying from 24 to 48 months. Both random and fixed effects meta-analyses were conducted. The quality of the studies varied from poor to excellent. Overall the risk reduction at 12 months was 54% (RR=0.463; 95% CI=0.33-0.64) with a Number Needed to Treat (NNT) of 9 (95% CI=6-15). Although the interventions differed, there was only mild heterogeneity and publication bias was small. All sub-analyses demonstrated effectiveness. Also 24 to 48-month follow-ups were associated with a risk reduction of 37% (RR=.635; 95% CI=0.44-0.92) and a NNT of 12 (95% CI=7-59). Sensitivity analysis excluding the methodologically weakest study showed that the findings were robust. Early detection and intervention in people at ultra-high risk of developing psychosis can be successful to prevent or delay a first psychosis. Antipsychotic medication showed efficacy, but more trials are needed. Omega-3 fatty acid needs replication. Integrated psychological interventions need replication with more methodologically sound studies. The findings regarding CBT appear robust, but the 95% confidence interval is still wide.

Baseline differences in clinical symptomatology between ultra high risk subjects with and without a transition to psychosis.

BACKGROUND The chance of transition to psychosis in patients at Ultra High Risk for developing psychosis (UHR) is 10-15%. The aim of present study was to investigate differences in baseline clinical symptomatology, general level of functioning (GAF-score) and genetic risk between UHR patients who did (UHR+T) or did not (UHR+NT) make a transition to psychosis. Sharpening UHR inclusion criteria may aid in improving prediction of transition to psychosis. METHOD The study sample was taken from 285 patients who were examined within the Dutch Prediction of Psychosis Study (DUPS) at the Academic Medical Center of the University of Amsterdam, the Netherlands. Out of 73 included UHR subjects, 18 made a transition to psychosis. Psychopathology was investigated with the Structured Interview for Prodromal Syndromes, Bonn Scale for the Assessment of Basic Symptoms and GAF-score. The follow-up period of the study was three years. RESULTS The UHR+T group showed more social anhedonia and withdrawal, more bizarre thinking and a lower GAF score at baseline than the UHR+NT group. CONCLUSIONS In agreement with the results of Cannon et al. [Cannon, T.D., Cadenhead, K., Cornblatt, B., Woods, S.W., Addington, J., Walker, E., Seidman, L.J., Perkins, D., Tsuang, M., McGlashan, T., Heinssen, R., 2008. Prediction of Psychosis in Youth at High Clinical Risk: A Multisite Longitudinal Study in North America. Arch. Gen. Psychiat. 65 (1) 28-37.], our study indicates that severity of specific symptoms at baseline is related to transition to psychosis in UHR subjects. These findings may contribute to a more accurate prediction of a first psychotic episode. Furthermore, symptoms that are increased at baseline in the UHR+T group could be a focus of cognitive behavioural therapy in the UHR period.

Early intervention and a five year follow up in young adults with a short duration of untreated psychosis: ethical implications

In a Dutch treatment intervention study of patients (n=76) with first psychotic episodes of schizophrenia the hypothesis tested was whether early differential treatment after an acute psychotic break improved outcome as compared with other studies. Patients had a relatively short duration of untreated psychosis. No significant effect between two treatment conditions on relapse rate was found. The 15-month intervention program kept the psychotic relapse rate as low as 15%; lower than comparable studies. Thus, the initial results were in support of the hypothesis. After completion of the 15 months study, patients were referred to other agencies and followed for five years. Results of the follow up study showed that the low relapse rate could not be maintained. Of the remaining 71 patients of the initial sample, 52% had one or more psychotic relapses, 25% developed chronic positive symptoms and 23% did not have another psychotic episode. In addition, the level of social functioning turned out to be low: the majority of patients were dependent upon their parents, few held down a skilled or paid job and also their quality of life seemed low, results indicate that early intervention may improve short term but not long term outcome in schizophrenia. Our results also suggest that referral to other mental health agencies after intervention is not sufficient. Continuity of outpatient care, including continuity of a professional relationship, continuity of support for the family, and the continuity in management of illness, medication and stress may be a key issue in the first five years after the onset of psychosis in schizophrenia. Early recognition and intervention may not nearly be as important for outcome as continuity in care and caregivers. At present, however, it remains questionable whether early intervention programs in first-episode patients with a short duration of untreated psychosis can offer the prospect of altering the course of schizophrenia without a sustained comprehensive treatment program.

Ultra high-risk state for psychosis and non-transition: a systematic review

BACKGROUND Most effort in ultra high-risk (UHR) research has been directed at defining the clinical and neurobiological characteristics of those UHR subjects who go on to develop psychosis. The characteristics and outcome of the remaining UHR subjects have remained relatively unexplored. METHOD We performed a systematic review of clinical UHR studies to investigate whether information was available on the characteristics and outcome of UHR subjects who did not convert to psychosis. RESULTS Of 2462 potentially relevant papers, 31 met inclusion criteria, i.e. 20 naturalistic and 11 intervention studies. On average 76% (range 46-92.6%) of the UHR patients made no transition to psychosis during follow-up (range 6 to 40 months). Nearly half of the studies provided no characteristics of those UHR subjects who did not develop psychosis. Six studies reported remission rates from initial UHR status (range 15.4% to 54.3%). Linear regression showed that more recent studies reported significantly lower transition rates as compared to earlier publications. An older mean age at baseline was associated with significant lower transition rates in publications with follow-ups exceeding 1 year. CONCLUSIONS Our review illustrates that the long-term outcome of UHR subjects that do not develop psychosis is to date under-investigated. The studies reporting remission rates suggest that UHR criteria capture a non-negligible proportion of subjects that do not convert to psychosis.

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.

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.

White matter fibertracking in first-episode schizophrenia, schizoaffective patients and subjects at ultra-high risk of psychosis

There is increasing evidence of white matter pathology in schizophrenia. The aim of this study was to examine whether white matter abnormalities found with diffusion tensor imaging (DTI) in previous schizophrenia studies are present in the early phase of the illness. DTI was performed at 3 T on 10 male patients with a first (n = 8) or second (n = 2) psychotic episode of schizophrenia or schizoaffective disorder, 10 male patients at ultra-high risk of psychosis with (pre)psychotic symptoms and 10 healthy controls. Fibertracts found to be abnormal in other DTI studies (uncinate and arcuate fasciculus, anterior and dorsal cingulum, subdivisions of the corpus callosum) were calculated and visualized; tract-specific measurements (fractional anisotropy and trace) were performed. No differences were found between the healthy subjects and the 2 patient groups. These preliminary findings suggest that there is no white matter pathology of these association tracts detectable with DTI in the early stages of schizophrenic illness in males. Our findings are in contrast with DTI abnormalities found in some other first-episode studies. This discrepancy in findings may be related to differences in subject characteristics and DTI methodology. Possible effects of age, gender, level of education and illicit substance use on DTI findings in schizophrenia are discussed.

Cognitive deficits associated with schizophrenia in velo-cardio-facial syndrome

Velo-cardio-facial syndrome (VCFS) is a genetic disorder associated with 22q11 deletion, a characteristic clinical phenotype, behavourial problems, specific cognitive deficits and a high rate of psychosis (particularly schizophrenia). The study of VCFS provides a unique opportunity to identify susceptibility genes for schizophrenia and its associated cognitive deficits. To date, there have been no studies investigating the impact of schizophrenia on cognitive function in adults with VCFS. Therefore we studied the neuropsychological profile of 28 adults with VCFS; 13 with schizophrenia (mean age (+/-S.D.) 34 years +/-11, IQ 71+/-11) and 15 without a history of psychosis (mean age 33 years +/-11, IQ 75+/-11). The VCFS group with schizophrenia compared to the VCFS group without schizophrenia performed significantly (P<0.05) worse on tests of: (1) spatial working memory and strategy formation; (2) the similarities sub-test of the Weschler Adult Intelligence Scale (WAIS); (3) visual recognition; (4) and attention. These deficits may reflect differences in the development and function of frontal brain regions, and this might increase the risk of developing schizophrenia in VCFS. Future studies will need to address how haploinsufficiency of genes on chromosome 22q11 might affect cognition and its relation to the development of psychosis.