The early Kraepelin´s dichotomy of schizophrenia and affective disorder - Evidence of separate diseases?ª

Belief updating in psychosis, depression and anxiety disorders: A systematic review across computational modelling approaches

Alterations in belief updating are proposed to underpin symptoms of psychiatric illness, including psychosis, depression, and anxiety. Key parameters underlying belief updating can be captured using computational modelling techniques, aiding the identification of unique and shared deficits, and improving diagnosis and treatment. We systematically reviewed research that applied computational modelling to probabilistic tasks measuring belief updating in stable and volatile (changing) environments, across clinical and subclinical psychosis (n = 17), anxiety (n = 9), depression (n = 9) and transdiagnostic samples (n = 9). Depression disorders related to abnormal belief updating in response to the valence of rewards, evidenced in both stable and volatile environments. Whereas psychosis and anxiety disorders were associated with difficulties adapting to changing contingencies specifically, indicating an inflexibility and/or insensitivity to environmental volatility. Higher-order learning models revealed additional difficulties in the estimation of overall environmental volatility across psychosis disorders, showing increased updating to irrelevant information. These findings stress the importance of investigating belief updating in transdiagnostic samples, using homogeneous experimental and computational modelling approaches.

Is that schizophrenia or frontotemporal dementia? Supporting clinicians in making the right diagnosis

Schizophrenia (SCH) and frontotemporal dementia (FTD) are neurobehavioral syndromes characterized by a profound alteration in personal and social conduct. Differential diagnosis between SCH and FTD remains a challenge. In this short narrative review, we summarize evidences regarding similarities and differences between these disorders to support clinicians in making the right diagnosis. Reports of FTD misdiagnosed as schizophrenia or schizophrenia-like psychosis are frequently reported in the literature. The behavioural variant of FTD (bvFTD) along with familial FTD characterized by delusions and hallucinations represent the medical conditions that best illustrate overlaps between psychiatry and neurology. Neuropsychological patterns of core deficits and anatomical and physiological brain alterations primarily concur in differencing such disorders while additional research on genetic alterations and their reflection on clinical phenotypes should be implemented in the near future. In some cases, a correct diagnosis should be made within an interdisciplinary clinical setting by complementary competences and follow-up visits to evaluate pathology evolution.

Changes in delusional dimensions and emotions over eight weeks of antipsychotic treatment in acute patients

Delusional experiences can be considered on a range of dimensions including conviction, distress, preoccupation, and disruption, which have been shown to be related to depression and anxiety. This study aimed to test the hypotheses that delusional conviction is less responsive to antipsychotic treatment than delusional distress and preoccupation, and that depression and anxiety reduce alongside improvements in delusional dimensions. Forty acutely ill inpatients with delusions were assessed during their early stage of antipsychotic treatment. Interview data were analysed using mixed models for repeated measures. There was a significant reduction in psychotic symptoms over eight weeks, after controlling for baseline dosage of antipsychotics. We found no differential rate of improvement across delusional dimensions, and all dimensions improved over time. However, conviction ratings remained relatively high throughout the eight weeks. There was no significant improvement in anxiety and depression, and delusional preoccupation covaried with anxiety and depression throughout eight weeks, suggesting a relationship between emotional and delusional processes during the early recovery phase of psychosis.

The Concept of Schizophrenia: From Unity to Diversity

After over 100 years of research without clarifying the aetiology of schizophrenia, a look at the current state of knowledge in epidemiology, genetics, precursors, psychopathology, and outcome seems worthwhile. The disease concept, created by Kraepelin and modified by Bleuler, has a varied history. Today, schizophrenia is considered a polygenic disorder with onset in early adulthood, characterized by irregular psychotic episodes and functional impairment, but incident cases occur at all ages with marked differences in symptoms and social outcome. Men’s and women’s lifetime risk is nearly the same. At young age, women fall ill a few years later and less severely than men, men more rarely and less severely later in life. The underlying protective effect of oestrogen is antagonized by genetic load. The illness course is heterogeneous and depressive mood the most frequent symptom. Depression and schizophrenia are functionally associated, and affective and nonaffective psychoses do not split neatly. Most social consequences occur at the prodromal stage. Neither schizophrenia as such nor its main symptom dimensions regularly show pronounced deterioration over time. Schizophrenia is neither a residual state of a neurodevelopmental disorder nor a progressing neurodegenerative process. It reflects multifactorial CNS instability, which leads to cognitive deficits and symptom exacerbations.

[Schizophrenia - a disorder in its own right?: results from 25 years of the ABC study]

BACKGROUND

The ABC schizophrenia study conducted by the same team over 25 years initially aimed at illuminating the onset, prodromal stage and sex differences in age at first hospitalization in schizophrenia. New hypotheses were systematically generated from the results achieved.

METHODS

A population-based sample of 276 first admission cases (232 first episodes, age 12-59 years), including a subsample of 130 first admissions (115 first episodes), were assessed to study prodromal stage, first illness episode, medium and long-term course and symptom dimensions in schizophrenia. The samples were compared with age and sex-matched healthy controls and with patients first admitted for unipolar depression. A total of 1,109 consecutive first admissions for schizophrenia spectrum disorders independent from the other study samples were assessed to study changes in symptomatology across the age range.

RESULTS

Before the onset of psychotic symptoms the prodromal stages of schizophrenia and severe and moderately severe depression are difficult to distinguish. The most frequent symptom in the course of schizophrenia, depressed mood, also represents the most frequent initial symptom in both disorders. Prodromal depression is a predictor of more depressive and positive symptoms in the first episode but not in the further course of the illness. Psychosis incidence for men, diagnosed according to ICD 9 (295, 297, 298.3/4), shows a pronounced peak at age 15-24 years, for women a lower peak at age 15-29 years and a second, still lower peak at the menopausal age of 45-49 years. The explanation, confirmed in animal experiments, lies in a protective effect of estrogen due to reduced D2 receptor sensitivity. The effect is antagonized by an elevated genetic risk. Functional and social impairment emerge even at the prodromal stage and the severity depends on sex and social status. Young men with schizophrenia show a less favorable social course because of the earlier age of onset and socially adverse illness behavior. Late onset is associated with a milder, primarily paranoid symptomatology and less severe social impairment. Schizophrenia is a disorder of all ages showing roughly equal life time incidence rates for men and women but considerable difference in certain periods of age. The symptom dimensions show a plateau-like course 2-5 years after the first episode. Hidden behind this picture are irregular symptom exacerbations which vary in duration. Schizophrenia conveys the picture of recurrent vulnerability to crisis and not of a stable residual state of disordered brain development or of a progressive neurodegenerative process.

Anxiety and depression in psychosis: a systematic review of associations with positive psychotic symptoms

OBJECTIVE

This review explores the influence of anxiety and depression on the experience of positive psychotic symptoms, and investigates the possibility of a causal role for anxiety and depression in the emergence and persistence of psychosis.

METHOD

A systematic literature search was undertaken, producing a number of papers which comment on the links between anxiety and depression, and the experience of delusions and hallucinations. In addition, evidence which could contribute to our understanding of the causal role of anxiety and depression was highlighted.

RESULTS

The findings show that both anxiety and depression are associated in meaningful ways with the severity of delusions and hallucinations, the distress they elicit and their content. However, the cross-sectional nature of the majority of studies and the focus on certain symptom subtypes tempers the validity of the findings. Data from non-clinical samples, studies which track the longitudinal course of psychosis and those which examine the impact of anxiety and depression on the prognosis for people experiencing psychosis, offer some support for the possibility of an influential role for anxiety and depression.

CONCLUSION

We conclude that anxiety and depression are related to psychotic symptom severity, distress and content and are also linked with sub-clinical experiences, symptom development, prognosis and relapse. These links may imply that anxiety and depression could be targets for therapeutic intervention. The article concludes with suggestions for further research, highlighting avenues which may circumvent the limitations of the body of work as it stands.

ABC Schizophrenia study: an overview of results since 1996

PURPOSE

The ABC Schizophrenia study, led by a single research team, investigated a schizophrenia sample systematically over quarter of a century. This paper summarises results from 1996 onwards. The initial goals were to explain the considerably higher age at first admission in women, and to obtain precise information on the onset and early course of schizophrenia as a prerequisite for early intervention.

METHOD

The study was hypothesis-driven. People with schizophrenia were compared in the prodrome and at first admission to those with unipolar depression and to healthy controls. We analysed the medium-term (5-year) and the long-term (12-year) course of schizophrenia, its symptom dimensions, social parameters and predictors.

SAMPLES

(1) 276 population-based first admissions (232 first episodes) of schizophrenia (age range 12-59 years); (2) a subsample of 130 first admissions for schizophrenia; (3) 130 first admissions for unipolar depression; (4) 130 healthy population controls and (5) 1,109 consecutive first admissions for schizophrenia spectrum disorder without an age limit.

RESULTS

The prodromal stages of schizophrenia and depression were very similar until positive symptoms appeared. The most frequent symptom in schizophrenia was depressed mood. The course of psychosis from prodrome to 12 years following first admission was very variable. From 5 to 12 years after first admission the course was characterised by irregular exacerbations of the main symptom dimensions, with no overall deterioration or improvement.

CONCLUSIONS

Schizophrenic psychosis and severe affective disorder, rather than representing discrete illnesses, probably mark different stages in the manifestation of psychopathology produced by various degrees of brain dysfunction.