Innovative screening models for the discovery of new schizophrenia drug therapies: an integrated approach

Introduction: Schizophrenia is a severe psychiatric disorder affecting millions worldwide. However, available treatment options do not fully address the disease. Whereas current antipsychotics may control psychotic symptoms, they seem notoriously ineffective in improving negative and cognitive symptoms or in preventing functional decline. As the etiology of schizophrenia eludes us, the development of valid animal models for screening new drug targets appears to be a strenuous task.Areas covered: In this review, the authors present the key concepts that validate animal models of schizophrenia, as well as the different screening approaches for novel schizophrenia treatments. The models covered are either based on major neurotransmitter systems or neurodevelopmental, immune, and genetic approaches.Expert opinion: Sadly, due to inertia, research focuses on developing 'anti-psychotics', instead of 'anti-schizophrenia' drugs that would tackle the entire syndrome of schizophrenia. Whereas no perfect model may ever exist, combining different experimental designs may enhance validity, as the over-reliance on a single model is inappropriate. Multi-model approaches incorporating vulnerability, the 'two-hit' hypothesis, and endophenotypes offer a promise for developing new strategies for schizophrenia treatment. Forward and reverse translation between preclinical and clinical research will increase the probability of success and limit failures in drug development.

Avatar Therapy for people with schizophrenia or related disorders

BACKGROUND

Many people with schizophrenia do not achieve satisfactory improvements in their mental state, particularly the symptom of hearing voices (hallucinations), with medical treatment.

OBJECTIVES

To examine the effects of Avatar Therapy for people with schizophrenia or related disorders.

SEARCH METHODS

In December 2016, November 2018 and April 2019, the Cochrane Schizophrenia Group's Study-Based Register of Trials (including registries of clinical trials) was searched, review authors checked references of all identified relevant reports to identify more studies and contacted authors of trials for additional information.

SELECTION CRITERIA

All randomised clinical trials focusing on Avatar Therapy for people with schizophrenia or related disorders.

DATA COLLECTION AND ANALYSIS

We extracted data independently. For binary outcomes, we calculated risk ratio (RR) and 95% confidence intervals (CI), on an intention-to-treat basis. For continuous data, we estimated the mean difference (MD) between groups and 95% CIs. We employed a fixed-effect model for analyses. We assessed risk of bias for included studies and created 'Summary of findings' tables using GRADE. Our main outcomes of interest were clinically important change in; mental state, insight, global state, quality of life and functioning as well as adverse effects and leaving the study early.

MAIN RESULTS

We found 14 potentially relevant references for three studies (participants = 195) comparing Avatar Therapy with two other interventions; treatment as usual or supportive counselling. Both Avatar Therapy and supportive counselling were given in addition (add-on) to the participants' normal care. All of the studies had high risk of bias across one or more domains for methodology and, for other risks of bias, authors from one of the studies were involved in the development of the avatar systems on trial and in another trial, authors had patents on the avatar system pending. 1. Avatar Therapy compared with treatment as usual When Avatar Therapy was compared with treatment as usual average endpoint Positive and Negative Syndrome Scale - Positive (PANSS-P) scores were not different between treatment groups (MD -1.93, 95% CI -5.10 to 1.24; studies = 1, participants = 19; very low-certainty evidence). A measure of insight (Revised Beliefs about Voices Questionnaire; BAVQ-R) showed an effect in favour of Avatar Therapy (MD -5.97, 95% CI -10.98 to -0.96; studies = 1, participants = 19; very low-certainty evidence). No one was rehospitalised in either group in the short term (risk difference (RD) 0.00, 95% CI -0.20 to 0.20; studies = 1, participants = 19; low-certainty evidence). Numbers leaving the study early from each group were not clearly different - although more did leave from the Avatar Therapy group (6/14 versus 0/12; RR 11.27, 95% CI 0.70 to 181.41; studies = 1, participants = 26; low-certainty evidence). There was no clear difference in anxiety between treatment groups (RR 5.54, 95% CI 0.34 to 89.80; studies = 1, participants = 19; low-certainty evidence). For quality of life, average Quality of Life Enjoyment and Satisfaction Questionnaire-Short Form (QLESQ-SF) scores favoured Avatar Therapy (MD 9.99, 95% CI 3.89 to 16.09; studies = 1, participants = 19; very low-certainty evidence). No study reported data for functioning. 2. Avatar Therapy compared with supportive counselling When Avatar Therapy was compared with supportive counselling (all short-term), general mental state (Psychotic Symptom Rating Scale (PSYRATS)) scores favoured the Avatar Therapy group (MD -4.74, 95% CI -8.01 to -1.47; studies = 1, participants = 124; low-certainty evidence). For insight (BAVQ-R), there was a small effect in favour of Avatar Therapy (MD -8.39, 95% CI -14.31 to -2.47; studies = 1, participants = 124; low-certainty evidence). Around 20% of each group left the study early (risk ratio (RR) 1.06, 95% CI 0.59 to 1.89; studies = 1, participants = 150; moderate-certainty evidence). Analysis of quality of life scores (Manchester Short Assessment of Quality of Life (MANSA)) showed no clear difference between groups (MD 2.69, 95% CI -1.48 to 6.86; studies = 1, participants = 120; low-certainty evidence). No data were available for rehospitalisation rates, adverse events or functioning.

AUTHORS' CONCLUSIONS

Our analyses of available data shows few, if any, consistent effects of Avatar Therapy for people living with schizophrenia who experience auditory hallucinations. Where there are effects, or suggestions of effects, we are uncertain because of their risk of bias and their unclear clinical meaning. The theory behind Avatar Therapy is compelling but the practice needs testing in large, long, well-designed, well-reported randomised trials undertaken with help from - but not under the direction of - Avatar Therapy pioneers.

Effects of antipsychotic drugs on insight in schizophrenia

Lack of insight is predominant in schizophrenia though the causes are still unclear. The present study was carried on to investigate the effect of three Second Generation Antipsychotics (SGAs) and Haloperidol on insight and the associations among different clusters of symptoms and insight. Fifty-five patients have been recruited at the moment of pharmacological switch needed for psychotic exacerbation, from other antipsychotic drugs to Olanzapine, Aripiprazole, Ziprasidone and Haloperidol. Patients have been followed for 6 months and evaluated at baseline, after 3 months and after 6 months. Regarding the insight improvement, all SGAs resulted more effective than Haloperidol, while no difference was detected among different SGAs. Concerning psychopathology, all SGAs showed a better efficacy than Haloperidol, positive symptoms apart. All SGAs showed a similar efficacy on all domains, except for negative symptoms which resulted less responsive to ziprasidone and haloperidol. An association between improvement of insight and psychopathology was detected. Furthermore, insight appears to be related to psychopathology severity, particularly to negative symptoms. However, the observed different effectiveness of Ziprasidone on negative symptoms and insight suggests that these psychopathological features may be not strictly related and, thus, they may be sustained by different psychopathological processes.