Could psychedelic drugs have a role in the treatment of schizophrenia? Rationale and strategy for safe implementation.

Schizophrenia is a widespread psychiatric disorder that affects 0.5-1.0% of the world's population and induces significant, long-term disability that exacts high personal and societal cost. Negative symptoms, which respond poorly to available antipsychotic drugs, are the primary cause of this disability. Association of negative symptoms with cortical atrophy and cell loss is widely reported. Psychedelic drugs are undergoing a significant renaissance in psychiatric disorders with efficacy reported in several conditions including depression, in individuals facing terminal cancer, posttraumatic stress disorder, and addiction. There is considerable evidence from preclinical studies and some support from human studies that psychedelics enhance neuroplasticity. In this Perspective, we consider the possibility that psychedelic drugs could have a role in treating cortical atrophy and cell loss in schizophrenia, and ameliorating the negative symptoms associated with these pathological manifestations. The foremost concern in treating schizophrenia patients with psychedelic drugs is induction or exacerbation of psychosis. We consider several strategies that could be implemented to mitigate the danger of psychotogenic effects and allow treatment of schizophrenia patients with psychedelics to be implemented. These include use of non-hallucinogenic derivatives, which are currently the focus of intense study, implementation of sub-psychedelic or microdosing, harnessing of entourage effects in extracts of psychedelic mushrooms, and blocking 5-HT2A receptor-mediated hallucinogenic effects. Preclinical studies that employ appropriate animal models are a prerequisite and clinical studies will need to be carefully designed on the basis of preclinical and translational data. Careful research in this area could significantly impact the treatment of one of the most severe and socially debilitating psychiatric disorders and open an exciting new frontier in psychopharmacology.

Hypnotizability is associated with a protective but not acquisitive self-presentation style.

Self-presentation refers to the behavioral strategies a person adopts to convey desired social images of oneself to other people. The Concern for Appropriateness Scale (CAS) measures a defensive and fearful social approach aimed at avoiding social threats whereas the Revised Self-Monitoring Scale (RSMS) measures an active and flexible social approach aimed at gaining power and status. In this study, a significant correlation was found between hypnotizability, as measured by the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) scores and CAS (r = .43, p = .002) but not between hypnotizability and RSMS (r = .070, p = .631). These results suggest that a protective self-presentation style may incline certain individuals to cooperate with hypnotic suggestions.

Glycine site agonists of the N-methyl-D-aspartate receptor and Parkinson's disease: a hypothesis.

Limitations of current pharmacological approaches to Parkinson's disease (PD) highlight the need for the development of nondopaminergic therapeutic strategies. The potential role of glutamatergic neurotransmission modulators, including those active at the N-methyl-D-aspartate receptor (NMDAR), is presently under investigation. Most literature proposes the use of NMDAR antagonists based on neurodegenerative theories of NMDAR function. Nevertheless, NMDAR antagonism has proven disappointing in clinical trials and may be associated with serious adverse events. More recent theories indicate that NMDAR target selectivity may be a cardinal prerequisite for efficacy, with present efforts being devoted primarily to development of NMDAR-NR2B subunit antagonists. We propose a novel hypothesis according to which NMDAR stimulation, accomplished through allosteric modulation via the glycine modulatory site, may be beneficial in late-phase PD. This hypothesis stems from: (1) meta-analysis of randomized controlled trials performed in schizophrenia, indicating that glycine site agonists (eg, glycine, D-serine) alleviate antipsychotic-induced parkinsonian symptoms; (2) clinical observations indicating that NMDAR hypofunction is associated with motor disturbances; (3) results of a preliminary D-serine trial in PD; (4) data indicating glycine efficacy in a rat tardive dyskinesia model; and (5) no evidence of excitotoxic damage following chronic high-dose glycine nutritional supplementation. This hypothesis is discussed in the context of glycine site agonist effects on intrasynaptic NMDAR subunits and striatal synaptic plasticity.

Hypnotizability and sensorimotor gating: a dopaminergic mechanism of hypnosis.

Dopaminergic mechanisms have been theorized to influence hypnotizability and sensorimotor gating. In this study, the authors investigated an association between sensorimotor gating, as measured by prepulse inhibition (PPI), and hypnotizability, as assessed by the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C). They found an inverse correlation between the SSHS:C and PPI. This finding, which replicates an earlier study, provides further evidence for a dopaminergic basis for hypnotizability and suggests additional avenues for research, including a method for possibly enhancing hypnotizability through pharmacological interventions.

Defensive self-presentation style is associated with reduced prepulse inhibition.

Prepulse inhibition (PPI) of the startle response is a cross-species measure of sensorimotor gating that provides a valuable tool for assessing the capacity to effectively screen out irrelevant sensory input. Accumulating evidence suggests that PPI deficits may correlate with impairments in social cognition, i.e. the ability to construct representation about others, oneself and the relations between others and oneself. Social cognition deficits are commonly encountered within the framework of psychiatric disorders. In this study 113 healthy volunteers completed psychopyhsiological measures of sensorimotor gating (PPI) and social self-presentation style (the Concern for Appropriate (CAS) and the Revised Self-Monitoring (RSMS) scales). CAS measures a defensive and fearful social approach aiming at avoiding social threats; RSMS measures an active and flexible social approach aiming at gaining power and status. Analyses revealed an inverse correlation between PPI at the 120 ms prepulse-to-pulse interval and total CAS scores (r=-0.19, p=0.04), as well as with the Attention to Social Comparison Information (ASCI) subscale of the CAS (r=-0.23, p=0.01). These findings suggest that reduced PPI may contribute to the tendency to adopt a defensive and fearful "getting along" social approach. This study is, to our knowledge, the first to assess the relationship between sensorimotor gating and self-presentational style in humans. Its findings suggest that very basic perceptual deficits that can be assessed using the PPI paradigm, may reflect information processing abnormalities that impact negatively upon the perception of complex social interactions.

Shiatsu as an adjuvant therapy for schizophrenia: an open-label pilot study.

CONTEXT: Studies have suggested a possible role for shiatsu in treating a variety of mental and physical ailments. OBJECTIVE: To determine if shiatsu can provide clinical benefit to individuals diagnosed with schizophrenia. DESIGN: An open-label pilot study. SETTING: An inpatient psychiatric ward at Herzog Memorial Hospital, Jerusalem, Israel. PATIENTS: Twelve hospitalized patients with chronic schizophrenia. INTERVENTION: Shiatsu treatment provided in a course of eight 40-minute biweekly sessions over 4 weeks. MAIN OUTCOME MEASURES: All subjects were evaluated at baseline, 2 weeks, 4 weeks (end of treatment), and 12 weeks (followup). The tools used for assessment included the Clinical Global Impression (CGI), the Brief Psychiatric Rating Scale (BPRS), the Positive and Negative Syndrome Scale (PANSS), the Hamilton Rating Scale for Depression (HAM-D), the Hamilton Anxiety Rating Scale (HAM-A), and the Nurses' Observation Scale for Inpatient Evaluation (NOSIE). Side effects were measured using the Simpson-Angus Scale for Extrapyramidal Symptoms (SAS) and the Abnormal Involuntary Movement Scale (AIMS). RESULTS: On all scales of psychopathology and side effects, the subjects showed a statistically and clinically significant improvement by the end of treatment. This improvement was maintained at the 12-week follow-up. These findings, while encouraging, must be considered preliminary and require confirmation and cross-validation in larger-scale controlled studies.

Association between arginine vasopressin 1a receptor (AVPR1a) promoter region polymorphisms and prepulse inhibition.

Arginine vasopressin and the arginine vasopressin 1a (AVPR1a) gene contribute to a range of social behaviors both in lower vertebrates and in humans. Human promoter-region microsatellite repeat regions (RS1 and RS3) in the AVPR1a gene region have been associated with autism spectrum disorders, prosocial behavior and social cognition. Prepulse inhibition (PPI) of the startle response to auditory stimuli is a largely autonomic response that resonates with social cognition in both animal models and humans. Reduced PPI has been observed in disorders including schizophrenia that are distinguished by deficits in social skills. In the current investigation association was examined between PPI and the AVPR1a RS1 and RS repeat regions and PPI in a group of 113 nonclinical subjects. Using a robust family-based strategy, association was observed between AVPR1a promoter-region repeat length, especially RS3) and PPI (30 ms: global p=0.04; 60 ms p=0.006; 120 ms p=0.008). Notably, longer RS3 alleles were associated with greater levels of prepulse inhibition. Using a short/long classification scheme for the repeat regions, significant association was also observed between all three PPI intervals (30, 60 and 120 ms) and both RS1 and RS3 polymorphisms (PBAT: FBAT-PC(2) statistic p=0.047). Tests of within-subject effects (SPSS GLM) showed significant sexxRS3 interactions at 30 ms (p=0.045) and 60 ms (p=0.01). Longer alleles, especially in male subjects, are associated with significantly higher PPI response, consistent with a role for the promoter repeat region in partially molding social behavior in both animals and humans. This is the first report in humans demonstrating a role of the AVPR1a gene in contributing to the PPI response to auditory stimuli.

Hypnotizability and blink rate: a test of the dopamine hypothesis.

Evidence suggests a role for central dopaminergic activity in determining an individual's level of hypnotizability. The authors measured the correlation between blink rate, which has been shown to correlate with central dopaminergic activity, and hypnotizability. Forty-eight healthy participants were evaluated for hypnotizability by the Harvard Group Scales of Hypnotic Susceptibility and the Stanford Hypnotic Susceptibility Scale: Form C. Blink rate was assessed under conditions of conversation, staring at a cross, listening to music, and resting. Contrary to their hypothesis, the authors found a negative correlation between hypnotizability and blink rate, accounted for primarily by the higher blink rates at rest in medium as compared to high hypnotizables. The results do not provide evidence for a role of dopamine in determining hypnotizability.

Reduced prepulse inhibition is associated with increased hypnotizability.

Hypnosis involves the manipulation of conscious attentional discrimination. The prepulse inhibition (PPI) paradigm assesses primary unconscious information processing. We investigated the correlation between hypnotizability and PPI of the startle reflex. Forty-eight healthy subjects were evaluated with the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) and acoustic PPI. Subjects were divided into low, medium, and high hypnotizable groups. The low-hypnotizable group showed a significantly higher inhibition of the startle response, at lead intervals 60 ms and 120 ms, than did the medium- and high-hypnotizable groups. We conclude that hypnotizability and PPI may be negatively correlated. These findings lend further support for the role of dopaminergic neurotransmission mechanisms in the determination of hypnotizability levels.

Placebo-controlled trial of lamotrigine added to conventional and atypical antipsychotics in schizophrenia.

BACKGROUND: Lamotrigine, a novel anticonvulsant drug having modulatory effects on glutamatergic neurotransmission, improves mood and cognition parameters in bipolar disorder. Recent studies suggest that when added to clozapine, lamotrigine treatment may result in significant positive symptoms reductions in schizophrenia. Similar effects were not observed in an open trial in which lamotrigine was used as adjuvant to nonclozapine antipsychotics. METHODS: Thirty-eight treatment-resistant schizophrenia inpatients receiving conventional and atypical antipsychotics enrolled in a 10-week, double-blind, placebo-controlled study, in which they were randomized in a 2:1 ratio to receive adjuvant treatment with lamotrigine, gradually titrated to a 400 mg/day dose, or placebo. Of these, 31 completed the trial. Measures of clinical efficacy and side effects were determined every other week. Serum levels of amino acids were assessed at the beginning and end of the study. RESULTS: In primary last observation carried forward analysis, no statistically significant between-group differences were observed; however, the completers' analyses revealed that lamotrigine treatment resulted in significant (p < or = .05) reductions in positive and general psychopathology symptoms, as measured by the Positive and Negative Syndrome Scale. No significant differences in lamotrigine effects were noted between conventional versus atypical antipsychotics. Lamotrigine treatment was well tolerated, and glutamate serum levels remained stable throughout the study. CONCLUSIONS: These preliminary findings 1) support the hypothesis that lamotrigine adjuvant treatment may improve positive symptoms and general psychopathology in schizophrenia, 2) suggest that beneficial effects may be achieved when lamotrigine is added to both conventional and atypical antipsychotics, and 3) warrant additional, larger scale trials.

Glycine and D-cycloserine attenuate vacuous chewing movements in a rat model of tardive dyskinesia.

Presently there is no established treatment for antipsychotic drugs-induced tardive dyskinesia (TD), which remains a major clinical issue in psychiatry. Based on the principles of the glutamatergic hypothesis of schizophrenia, the amino acid glycine (GLY) and the antituberculosis drug D-cycloserine (DCS) have been assessed, during the last decade, as adjuvants to antipsychotic drugs. Observations stemming from these studies suggest that, in addition to improving schizophrenia symptoms, these compounds may also be beneficial against drug-induced dyskinesias. In order to investigate this hypothesis, GLY and DCS effects were studied using the putative TD analogue vacuous chewing movements (VCM) rat model. Following 24 weeks of treatment with haloperidol decanoate (0.38 mg/kg/4 weeks) rats (N=40) were randomized to receive one intraperitoneal injection with 1.6 g/kg GLY, 10 mg/kg ("low dose") DCS; 100 mg/kg ("high dose") DCS or saline ("placebo"), respectively. Behavior was videotaped at intervals during the experiment and all VCM, rearing, grooming and immobility episodes were analyzed and scored. A control group (N=9) received saline for 24 weeks. Haloperidol administration decreased motor activity and significantly induced VCM. High dose DCS significantly reduced VCM without affecting other motor parameters. GLY treatment resulted in significantly less VCM but also reduced rearing, grooming and mobility. In contrast, low dose DCS and placebo did not significantly affect any of these parameters. These findings indicate that the use of GLY and DCS results in attenuation of VCM in rats and may have an effect on TD in humans. Clinical trials with this type of compounds for patients suffering from TD are warranted.

High-dose glycine added to olanzapine and risperidone for the treatment of schizophrenia.

BACKGROUND: Clinical trials indicate that glycine site agonists of the N-methyl-D-aspartate (NMDA) receptors may reduce negative and cognitive symptoms in treatment-resistant schizophrenia when used as adjuvants to conventional antipsychotics but possibly not to clozapine. In this study, we assessed whether high-dose glycine may also be therapeutically beneficial when added to olanzapine and risperidone treatment. METHODS: Seventeen olanzapine- or risperidone-treated schizophrenia patients participated in a double-blind, placebo-controlled, 6-week crossover treatment trial with.8 g/kg/day glycine added to their ongoing antipsychotic medication. Clinical assessments were performed biweekly throughout the study. Clinical laboratory parameters and amino acid serum levels were monitored. RESULTS: Glycine treatment was well tolerated and resulted in a significant (p <.0001) 23% +/- 8% reduction in negative symptoms. Significant improvements were also registered in cognitive and positive symptoms. The negative symptoms improvement remained significant even following covariation for changes in other symptom clusters and extrapyramidal side effects. High posttreatment glycine serum levels significantly predicted (r =.60) clinical response. CONCLUSIONS: These findings indicate that the efficacy of olanzapine and risperidone may be augmented using high-dose adjuvant glycine treatment and suggest that these atypical antipsychotics may affect NMDA receptor-mediated neurotransmission differently than clozapine.

[Hypnosis: clinical applications].

BACKGROUND: Hypnosis has a wide variety of applications in medicine. In recent years, recognition has grown for the need to subject the effectiveness of hypnosis to accepted research standards of clinical medicine. PURPOSE: This article aims to review salient studies of the effectiveness of hypnosis in several areas of medicine where hypnosis is commonly employed: analgesia, preparation for medical and surgical procedures, asthma, digestive disturbances, dermatological disorders, bleeding disorders, postsurgical and post-chemotherapeutic nausea and vomiting, and smoking cessation. METHODS: This survey emphasizes studies that fulfill accepted standards of clinical research, including randomization, control groups, and adequate sample size. RESULTS: Firm empirical evidence is to be found for the effectiveness of hypnosis in analgesia. In the other areas reviewed there is also some evidence for the possible clinical value for hypnosis. CONCLUSIONS: Additional research will be necessary to determine the proper place of hypnosis in clinical medical care.