Negative Symptoms in Schizophrenia

In schizophrenia, an abnormal reduction in neuronal gamma oscillations (30-100 Hz) is associated with negative symptoms such as cognitive dysfunction. The literature suggests that rescuing gamma oscillations through non-invasive brain stimulation may be an accessible and safe add-on strategy to mitigate negative symptoms. Here, a stimulation protocol based on gamma visual stimulation will be tested. This pilot study will follow an uncontrolled clinical trial design: A minimum of ten patients diagnosed with schizophrenia or a schizoaffective disorder and predominant negative symptoms will be recruited at Klinikum rechts der Isar. They will undergo a multisession stimulation protocol, consisting of one hour of 40 Hz visual stimulation per day over five consecutive days, during which they will be encouraged to fall asleep. An equal number of patients will be recruited for a treatment-as-usual group without intervention. Pre- and post-assessments will include EEG, a cognitive test battery (THINC-IT), a mood scale (PANAS), and a schizophrenia symptom scale (PANSS). This study's results will inform on the feasibility of gamma visual stimulation as a potential add-on intervention in schizophrenia.

The purpose of this study is to assess the effectiveness of rTMS on the negative symptoms of schizophrenia in real conditions. It will also provide a regulatory framework to rTMS treatments under these conditions. 4 types of rTMS protocols are proposed, allowing to adapt to patients and their tolerances.Treatment lasts between 2 and 4 weeks, with a follow-up period of 3 months after treatment to observe relapses.To assess the evolution of negative symptoms between baseline and the end of treatment, investigators use SANS (Scale for the Assessment of Negative Symptoms).

This study aims to validate the Lithuanian version of the Brief Negative Symptoms Scale, Calgary Depression Scale for Schizophrenia, and Schizophrenia Cognition Rating Scale in a Lithuanian sample. This will be done by comparing results obtained from the Brief Negative Symptoms Scale, Calgary Depression Scale for Schizophrenia, and Schizophrenia Cognition Rating Scale with results obtained from the Positive and Negative Symptoms Scale, the Montgomery Asberg Depression Rating Scale, and the Montreal Cognitive Assessment test.

There is a clear rationale for developing interventions targeting negative symptoms of schizophrenia as these are a stronger indicator of current and future functioning than positive symptoms and because they respond poorly to medication and existing psychological interventions. This is reflected in the NIMH-MATRICS consensus statement that emphasised that persistent negative symptoms represent an unmet therapeutic need for patients suffering from schizophrenia. The purpose of this study is to evaluate, in a scientific manner, the intervention developed by Swanson et al. 2021: Metacognitive Training (MCT) Minus. The MCT was adapted to target negative symptoms in psychotic disorders (e.g. schizophrenia, schizoaffective or non-affective functional psychosis) as the original version of the intervention focused exclusively on positive symptoms. The specific aim is to study whether MCT Minus is a promising treatment for the intended population in terms of reductions in negative symptoms, severity of defeatist attitudes, internalised stigma, and depression as well as improvements in reflective ability and overall functioning. The research will add to existing research by identifying and measuring potential mechanisms of change for negative symptoms (i.e., defeatist attitudes, reflective functioning, stigma and depression). It will also add to the existing evidence base by measuring whether the cognitive biases addressed in MCT lead to changes in the wider conceptualisation of metacognition used elsewhere and whether the promising results seen in the feasibility study of MCT Minus can be replicated in a randomised controlled trial (RCT) with a control group and a blinded assessor. The researchers also hope to replicate the findings of a previous study, where MCT was found to be related to the modulation of default-mode network (DMN) homogeneity in schizophrenia, an area thought to be involved in self- and other-reflectivity.