Phenylketonuria (PKU), a genetic metabolic disorder that is characterized by the inability to convert phenylalanine to tyrosine, leads to severe intellectual disability and other cerebral complications if left untreated. Dietary treatment, initiated soon after birth, prevents most brain-related complications. A leading hypothesis postulates that a shortage of brain monoamines may be associated with neurocognitive deficits that are observable even in early-treated PKU. However, there is a paucity of evidence as yet for this hypothesis.

We therefore assessed in vivo striatal dopamine D2/3 receptor (D2/3R) availability and plasma monoamine metabolite levels together with measures of impulsivity and executive functioning in 18 adults with PKU and average intellect (31.2 ± 7.4 years, nine females), most of whom were early and continuously treated. Comparison data from 12 healthy controls that did not differ in gender and age were available.

Mean D2/3R availability was significantly higher (13%; p = 0.032) in the PKU group (n = 15) than in the controls, which may reflect reduced synaptic brain dopamine levels in PKU. The PKU group had lower plasma levels of homovanillic acid (p < 0.001) and 3-methoxy-4-hydroxy-phenylglycol (p < 0.0001), the predominant metabolites of dopamine and norepinephrine, respectively. Self-reported impulsivity levels were significantly higher in the PKU group compared with healthy controls (p = 0.033). Within the PKU group, D2/3R availability showed a positive correlation with both impulsivity (r = 0.72, p = 0.003) and the error rate during a cognitive flexibility task (r = 0.59, p = 0.020).

These findings provide further support for the hypothesis that executive functioning deficits in treated adult PKU may be associated with cerebral dopamine deficiency.

Patients with a deletion at chromosome 22q11.2 (22q11DS) have 30% lifetime risk of developing a psychosis. People fulfilling clinical criteria for ultra-high risk (UHR) for psychosis have 30% risk of developing a psychosis within 2 years. Both high-risk groups show white-matter (WM) abnormalities in microstructure and volume compared to healthy controls (HC), which have been related to psychotic symptoms. Comparisons of WM pathology between these two groups may specify WM markers related to genetic and clinical risk factors.

Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) were assessed using diffusion tensor magnetic resonance imaging (MRI), and WM volume with structural MRI, in 23 UHR patients, 21 22q11DS patients, and 33 HC.

Compared to UHR patients 22q11DS patients had (1) lower AD and RD in corpus callosum (CC), cortical fasciculi, and anterior thalamic radiation (ATR), (2) higher FA in CC and ATR, and (3) lower occipital and superior temporal gyrus WM volume. Compared to HC, 22q11DS patients had (1) lower AD and RD throughout cortical fasciculi and (2) higher FA in ATR, CC and inferior fronto-occipital fasciculus. Compared to HC, UHR patients had (1) higher mean MD, RD, and AD in CC, ATR and cortical fasciculi, (2) no differences in FA.

UHR and 22q11DS patients share a susceptibility for developing psychosis yet were characterized by distinct patterns of WM alterations relative to HC. While UHR patients were typified by signs suggestive of aberrant myelination, 22q11DS subjects showed signs suggestive of lower axonal integrity.

Current ultra-high-risk (UHR) criteria appear insufficient to predict imminent onset of first-episode psychosis, as a meta-analysis showed that about 20% of patients have a psychotic outcome after 2 years. Therefore, we aimed to develop a stage-dependent predictive model in UHR individuals who were seeking help for co-morbid disorders.

Baseline data on symptomatology, and environmental and psychological factors of 185 UHR patients (aged 14–35 years) participating in the Dutch Early Detection and Intervention Evaluation study were analysed with Cox proportional hazard analyses.

At 18 months, the overall transition rate was 17.3%. The final predictor model included five variables: observed blunted affect [hazard ratio (HR) 3.39, 95% confidence interval (CI) 1.56–7.35, p < 0.001], subjective complaints of impaired motor function (HR 5.88, 95% CI 1.21–6.10, p = 0.02), beliefs about social marginalization (HR 2.76, 95% CI 1.14–6.72, p = 0.03), decline in social functioning (HR 1.10, 95% CI 1.01–1.17, p = 0.03), and distress associated with suspiciousness (HR 1.02, 95% CI 1.00–1.03, p = 0.01). The positive predictive value of the model was 80.0%. The resulting prognostic index stratified the general risk into three risk classes with significantly different survival curves. In the highest risk class, transition to psychosis emerged on average ⩾8 months earlier than in the lowest risk class.

Predicting a first-episode psychosis in help-seeking UHR patients was improved using a stage-dependent prognostic model including negative psychotic symptoms (observed flattened affect, subjective impaired motor functioning), impaired social functioning and distress associated with suspiciousness. Treatment intensity may be stratified and personalized using the risk stratification.

Although there is evidence for the effectiveness of interventions for psychosis among ultra-high-risk (UHR) groups, health economic evaluations are lacking. This study aimed to determine the cost effectiveness and cost–utility of cognitive–behavioural therapy (CBT) to prevent first-episode psychosis.

The Dutch Early Detection and Intervention Evaluation study was a randomized controlled trial of 196 UHR patients with an 18-month follow-up. All participants were treated with routine care (RC) for non-psychotic disorders. The experimental group (n = 95) received add-on CBT to prevent first-episode psychosis. We report the intervention, medical and travel costs, as well as costs arising from loss of productivity. Treatment response was defined as psychosis-free survival and quality-adjusted life years (QALYs) gained.

In the cost-effectiveness analysis, the proportion of averted psychoses was significantly higher in the CBT condition (89.5% v. 76.2%). CBT showed a 63.7% probability of being more cost effective, because it was less costly than RC by US$844 (£551) per prevented psychosis. In the cost–utility analysis, QALY health gains were slightly higher for CBT than for RC (0.60 v. 0.57) and the CBT intervention had a 52.3% probability of being the superior treatment because, for equal or better QALY gains, the costs of CBT were lower than those of RC.

Add-on preventive CBT for UHR resulted in a significant reduction in the incidence of first psychosis. QALY gains show little difference between the two conditions. The CBT intervention proved to be cost saving.

There is an increasing interest in cognitive–behavioural therapy (CBT) interventions targeting negative symptoms in schizophrenia. To date, CBT trials primarily focused on positive symptoms and investigated change in negative symptoms only as a secondary outcome. To enhance insight into factors contributing to improvement of negative symptoms, and to identify subgroups of patients that may benefit most from CBT directed at ameliorating negative symptoms, we reviewed all available evidence on these outcomes.

A systematic search of the literature was conducted in PsychInfo, PubMed and the Cochrane register to identify randomized controlled trials reporting on the impact of CBT interventions on negative symptoms in schizophrenia. Random-effects meta-analyses were performed on end-of-treatment, short-term and long-term changes in negative symptoms.

A total of 35 publications covering 30 trials in 2312 patients, published between 1993 and 2013, were included. Our results showed studies’ pooled effect on symptom alleviation to be small [Hedges’ g = 0.093, 95% confidence interval (CI) −0.028 to 0.214, p = 0.130] and heterogeneous (Q = 73.067, degrees of freedom = 29, p < 0.001, τ 2 = 0.081, I 2 = 60.31) in studies with negative symptoms as a secondary outcome. Similar results were found for studies focused on negative symptom reduction (Hedges’ g = 0.157, 95% CI −0.10 to 0.409, p = 0.225). Meta-regression revealed that stronger treatment effects were associated with earlier year of publication, lower study quality and with CBT provided individually (as compared with group-based).

The co-occurring beneficial effect of conventional CBT on negative symptoms found in older studies was not supported by more recent studies. It is now necessary to further disentangle effective treatment ingredients of older studies in order to guide the development of future CBT interventions aimed at negative symptom reduction.

Deep brain stimulation (DBS) is a promising new treatment for patients with treatment-refractory obsessive–compulsive disorder (OCD). However, since most DBS patients only show a partial response, the treatment still needs to be improved. In this study we hypothesized that cognitive–behavioural therapy (CBT) could optimize the post-operative management in DBS and we evaluated the efficacy of CBT as augmentation to DBS targeted at the nucleus accumbens.

A total of 16 patients with treatment-refractory OCD were treated with DBS targeted at the nucleus accumbens. After stabilization of decline in OCD symptoms, a standardized 24-week CBT treatment programme was added to DBS in an open-phase trial of 8 months. Changes in obsessive–compulsive, anxiety and depressive symptoms were evaluated using the Yale–Brown Obsessive Compulsive Scale, Hamilton Anxiety Scale and Hamilton Rating Scale for Depression.

Following the addition of CBT to DBS, a significant decrease in obsessive–compulsive symptoms was observed, but not in anxiety and depressive symptoms. In a subsequent double-blind phase, in which stimulation was discontinued, OCD symptoms returned to baseline (relapse) and anxiety and depressive symptoms worsened (rebound) compared with baseline.

The results of this explorative study suggest that a combined treatment of accumbens DBS and CBT may be optimal for improving obsessive–compulsive symptoms in treatment-refractory OCD. However, a subsequent randomized controlled trial is necessary to draw firm conclusions. It seems that DBS results in affective changes that may be required to enable response prevention in CBT. This may indicate that DBS and CBT act as two complementary treatments.

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).

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.

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.

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.

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.

Participants 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.

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.

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.

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).

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.

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.

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.