Pregnenolone as an adjunct to risperidone for treatment of women with schizophrenia: A randomized double-blind placebo-controlled clinical trial

Multimodal electrophysiological analyses reveal that reduced synaptic excitatory neurotransmission underlies seizures in a model of NMDAR antibody-mediated encephalitis

Seizures are a prominent feature in N-Methyl-D-Aspartate receptor antibody (NMDAR antibody) encephalitis, a distinct neuro-immunological disorder in which specific human autoantibodies bind and crosslink the surface of NMDAR proteins thereby causing internalization and a state of NMDAR hypofunction. To further understand ictogenesis in this disorder, and to test a potential treatment compound, we developed an NMDAR antibody mediated rat seizure model that displays spontaneous epileptiform activity in vivo and in vitro. Using a combination of electrophysiological and dynamic causal modelling techniques we show that, contrary to expectation, reduction of synaptic excitatory, but not inhibitory, neurotransmission underlies the ictal events through alterations in the dynamical behaviour of microcircuits in brain tissue. Moreover, in vitro application of a neurosteroid, pregnenolone sulphate, that upregulates NMDARs, reduced established ictal activity. This proof-of-concept study highlights the complexity of circuit disturbances that may lead to seizures and the potential use of receptor-specific treatments in antibody-mediated seizures and epilepsy.

Efficacy and safety of anti-inflammatory agents in treatment of psychotic disorders - A comprehensive systematic review and meta-analysis

OBJECTIVE

Antipsychotic effects of immunomodulating drugs have been suggested; however, a thorough, comprehensive meta-analysis on the effect and safety of anti-inflammatory add-on treatment on psychotic disorders is lacking.

METHOD

Multiple databases were searched up until February 2020. Only double-blinded, randomized, placebo-controlled clinical trials (RCTs) were included. Primary outcomes were change in total psychopathology and adverse events. Secondary outcomes included, amongst others, positive and negative symptoms, general psychopathology and cognitive domains. We performed random-effects meta-analyses estimating mean differences (MD) and standardized mean differences (SMD) for effect sizes.

RESULTS

Seventy RCTs (N = 4104) were included, investigating either primarily anti-inflammatory drugs, i.e. drugs developed for immunomodulation, such as NSAIDs, minocycline and monoclonal antibodies (k = 15), or drugs with potential anti-inflammatory properties (k = 55), e.g. neurosteroids, N-acetyl cysteine, estrogens, fatty acids, statins, and glitazones. Antipsychotics plus anti-inflammatory treatment, compared to antipsychotics plus placebo, was associated with a PANSS scale MD improvement of -4.57 (95%CI = -5.93 to -3.20) points, corresponding to a SMD effect size of -0.29 (95%CI = -0.40 to -0.19). Trials on schizophrenia (MD = -6.80; 95%CI, -9.08 to -4.52) showed greater improvement (p < 0.01) than trials also including other psychotic disorders. However, primarily anti-inflammatory drugs (MD = 4.00; 95%CI = -7.19 to -0.80) were not superior (p = 0.69) to potential anti-inflammatory drugs (MD = 4.71; 95%CI = -6.26 to -3.17). Furthermore, meta-regression found that smaller studies showed significantly larger effect sizes than the larger studies (p = 0.0085), and only 2 studies had low risk of bias on all domains. Small but significant effects were found on negative symptoms (MD = -1.29), positive symptoms (MD = -0.53), general psychopathology (MD = -1.50) and working memory (SMD = 0.21). No differences were found regarding adverse events, but only 26 studies reported hereon.

CONCLUSIONS

Anti-inflammatory add-on treatment to antipsychotics showed improvement of psychotic disorders; however, no superiority was found in primarily anti-inflammatory drugs, raising the question of the mechanism behind the effect, and treatment effect might be overestimated due to the large number of small studies.

Vortioxetine as adjunctive therapy to risperidone for treatment of patients with chronic schizophrenia: A randomised, double-blind, placebo-controlled clinical trial

INTRODUCTION AND OBJECTIVES

Vortioxetine, a novel antidepressant, may be an interesting candidate for adjunctive therapy of schizophrenia. Our primary objective was to investigate the effect of vortioxetine on negative symptoms, with the assessment of positive, general psychopathology and total symptoms as our secondary goal.

METHODS

This was an eight-week randomised, double-blind, placebo-controlled, parallel-group clinical trial, in which 78 inpatients with chronic schizophrenia were stabilised with risperidone (4-6 mg/day) for two months before being assigned to adjunctive vortioxetine (10 mg b.i.d.) or placebo. The patients were assessed using the Positive and Negative Syndrome Scale (PANSS), Extrapyramidal Symptom Rating Scale and Hamilton Depression Rating Scale during the study course. All participants had a PANSS negative symptoms subscale score of ⩾16 at baseline. Sixty-eight patients completed the trial.

RESULTS

Vortioxetine improved the negative symptoms score as the primary outcome and total PANSS score as a secondary outcome significantly better than placebo from baseline to end point at week 8, accompanied by significant time × treatment interactions and effect sizes (negative symptoms: mean difference (95% confidence interval (CI)) = -1.82 (-2.73 to -0.92); total scores: mean difference (95% CI) = -2.09 (-3.16 to -1.01). No significant difference was detected for changes in positive symptoms score or PANSS general psychopathology score as the other secondary outcomes from baseline to end point between the two treatment arms. The incidence of adverse events was comparable between groups.

CONCLUSIONS

This is the first study to provide evidence for the therapeutic effect of vortioxetine on negative symptoms as an adjunctive to treatment with antipsychotics in patients with schizophrenia.

Role of the Endocannabinoid System in the Pathophysiology of Schizophrenia: Implications for Pharmacological Intervention

The term schizophrenia describes a group of multifaceted psychiatric conditions causing significant impairment of the quality of life of affected patients. Although multiple pharmacological treatment options exist, e.g. first- or second-generation antipsychotics, these therapeutics often cause disturbing side effects, such as extrapyramidal symptoms, prolactin increase, sexual dysfunction and/or metabolic syndrome. Furthermore, cognitive impairments and negative symptoms, two factors significantly influencing the course and outcome, are not sufficiently addressed by the available antipsychotics. Since its discovery, multiple clinical and preclinical studies have linked the endocannabinoid system to schizophrenia. Both the endocannabinoid anandamide and the cannabinoid CB₁ receptor are deeply linked to underlying disease processes. Based hereon, clinical trials in schizophrenia have explored cannabidiol, a primary component of Cannabis sativa, and rimonabant, a partial antagonist to the CB₁ receptor. While the latter did not reveal positive results, cannabidiol significantly ameliorated psychotic symptoms, which was associated with an increase in anandamide serum levels. However, the exact mechanisms of the antipsychotic effects of cannabidiol are not fully understood, and, furthermore, only a limited number of clinical trials in humans have been concluded to date. Thus, the level of proof of safety and efficacy required to approve the therapeutic use of cannabidiol in schizophrenia is currently lacking. However, cannabidiol is a promising candidate as an effective and mechanistically different antipsychotic treatment with a favourable side-effect profile. We therefore conclude that further studies are urgently needed to clarify the antipsychotic effects and safety profile of cannabidiol, and to fully explore its potential antipsychotic mechanism.

L-carnosine as an add-on to risperidone for treatment of negative symptoms in patients with stable schizophrenia: A double-blind, randomized placebo-controlled trial

Since l-carnosine has shown effectiveness in improvement of cognition in patients with schizophrenia, this 8-week, randomized, double-blind, placebo-controlled pilot study was conducted. Sixty-three patients with chronic schizophrenia, who were clinically stable on a stable dose of risperidone, entered the study. The patients were randomly assigned to l-carnosine (2 gr/day in two divided doses) or placebo for eight weeks. The patients were assessed using the positive and negative syndrome scale (PANSS), extrapyramidal symptom rating scale (ESRS), and Hamilton depression rating scale (HDRS) during the study course. Sixty patients completed the trial. L-carnosine resulted in greater improvement of negative scores as well as total PANSS scores but not positive subscale scores compared to placebo. HDRS scores and its changes did not differ between the two groups. Both groups demonstrated a constant ESRS score during the trial course. Frequency of other side effects was not significantly different between the two groups. In a multiple regression analysis model (controlled for positive, general psychopathology, depressive and extrapyramidal symptoms, as well as other variables), the treatment group significantly predicted changes in primary negative symptoms. In conclusion, l-carnosine add-on therapy can safely and effectively reduce the primary negative symptoms of patients with schizophrenia.