Amphetamine challenge test, response to treatment, and lateral ventricle size in schizophrenia

MDMA for the Treatment of Negative Symptoms in Schizophrenia

The profound economic burden of schizophrenia is due, in part, to the negative symptoms of the disease, which can severely limit daily functioning. There is much debate in the field regarding their measurement and classification and there are no FDA-approved treatments for negative symptoms despite an abundance of research. 3,4-Methylenedioxy methamphetamine (MDMA) is a schedule I substance that has emerged as a novel therapeutic given its ability to enhance social interactions, generate empathy, and induce a state of metaplasticity in the brain. This review provides a rationale for the use of MDMA in the treatment of negative symptoms by reviewing the literature on negative symptoms, their treatment, MDMA, and MDMA-assisted therapy. It reviews recent evidence that supports the safe and potentially effective use of MDMA to treat negative symptoms and concludes with considerations regarding safety and possible mechanisms of action.

Systematic review and exploratory meta-analysis of the efficacy, safety, and biological effects of psychostimulants and atomoxetine in patients with schizophrenia or schizoaffective disorder

OBJECTIVE

Our aim was to summarize the efficacy and safety of atomoxetine, amphetamines, and methylphenidate in schizophrenia.

METHODS

We undertook a systematic review, searching PubMed/Scopus/Clinicaltrials.gov for double-blind, randomized, placebo-controlled studies of psychostimulants or atomoxetine in schizophrenia published up to 1 January 2017. A meta-analysis of outcomes reported in two or more studies is presented.

RESULTS

We included 22 studies investigating therapeutic effects of stimulants (k=14) or measuring symptomatic worsening/relapse prediction after stimulant challenge (k=6). Six studies of these two groups plus one additional study investigated biological effects of psychostimulants or atomoxetine. No effect resulted from interventional studies on weight loss (k=1), smoking cessation (k=1), and positive symptoms (k=12), and no improvement was reported with atomoxetine (k=3) for negative symptoms, with equivocal findings for negative (k=6) and mood symptoms (k=2) with amphetamines. Attention, processing speed, working memory, problem solving, and executive functions, among others, showed from no to some improvement with atomoxetine (k=3) or amphetamines (k=6). Meta-analysis did not confirm any effect of stimulants in any symptom domain, including negative symptoms, apart from atomoxetine improving problem solving (k=2, standardized mean difference (SMD)=0.73, 95% CI=0.10-1.36, p=0.02, I2=0%), and trending toward significant improvement in executive functions with amphetamines (k=2, SMD=0.80, 95% CI=-1.68 to +0.08, p=0.08, I2=66%). In challenge studies, amphetamines (k=1) did not worsen symptoms, and methylphenidate (k=5) consistently worsened or predicted relapse. Biological effects of atomoxetine (k=1) and amphetamines (k=1) were cortical activation, without change in β-endorphin (k=1), improved response to antipsychotics after amphetamine challenge (k=2), and an increase of growth hormone-mediated psychosis with methylphenidate (k=2). No major side effects were reported (k=6).

CONCLUSIONS

No efficacy for stimulants or atomoxetine on negative symptoms is proven. Atomoxetine or amphetamines may improve cognitive symptoms, while methylphenidate should be avoided in patients with schizophrenia. Insufficient evidence is available to draw firm conclusions.

A systematic review of psychostimulant treatment of negative symptoms of schizophrenia: challenges and therapeutic opportunities

BACKGROUND

Primary negative symptoms of schizophrenia (NSS) contribute heavily to functional disability and treatment of these symptoms continues to be a major unmet need even when the positive (psychotic) symptoms are controlled. The modified dopamine (DA) hypothesis posits that positive symptoms are associated with increased DA activity in the mesolimbic tract whereas NSS and cognitive symptoms are associated with decreased DA activity in the mesocortical (frontal) region. Several studies have reported improvement in NSS with DA agonist use, but with varying degrees of risk for triggering psychotic symptoms, especially in the absence of concurrent antipsychotic drug treatment. This article aims to examine older and newer evidence suggesting that psychostimulants may have a potential therapeutic role in the treatment of NSS together with a thorough review of the potential risks and benefits of psychostimulant administration in individuals with schizophrenia.

METHODS

A systematic search of relevant literature using electronic databases, reference lists, and data presented at recent meetings was conducted.

RESULTS

Improvement of NSS after psychostimulant administration is reviewed both in challenge and treatment paradigms with various agents such as methylphenidate, amphetamine, and modafinil or armodafinil. The literature points to evidence that, used adjunctively, DA agonists may improve NSS without worsening of positive symptoms in selected patients who are stable and treated with effective antipsychotic medications. Several areas of inadequate study and limitations are identified including small study samples, single-site trials, varying rigor of bias control, the dose and the duration of adjunctive psychostimulant administration, and the potential for development of tolerance.

CONCLUSION

Large, controlled clinical trials to further characterize effects of psychostimulants on NSS in carefully selected patients are warranted.

Prevalence of psychotic symptoms in substance users: a comparison across substances

BACKGROUND

Psychotic symptoms (delusions and hallucinations) are reported to be increased among persons using illicit substances, but little is known about the comparative frequency with which the symptoms occur with abuse of different substances. To establish this, we interviewed individuals who had wide experience of commonly used drugs.

METHODS

Four hundred seventy-six intravenous drug users, crack-cocaine users, and heroin snorters recruited via street outreach were interviewed using the Composite International Diagnostic Interview-Substance Abuse Model to assess dependence on a number of substances including amphetamines, cannabis, cocaine, and opioids. As a part of this assessment, we assessed a history of delusions and hallucinations in the context of use of, or withdrawal from, these specific substances.

RESULTS

From 27.8% to 79.6% users of amphetamine, cannabis, cocaine, and opiates met Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, dependence for that specific substance. The prevalence of psychotic symptoms associated with each specific substance ranged from users with no diagnosis to users with severe dependence as follows: amphetamines (5.2%-100%), cannabis (12.4%-80.0%), cocaine (6.7%-80.7%), and opiates (6.7%-58.2%). The risk of psychotic symptoms increased for respondents who abused (odds ratio [OR], 12.2) or had mild (OR, 17.1), moderate (OR, 47.0), or severe dependence (OR, 114.0) on cocaine when compared to those who were users with no diagnosis. A similar pattern was evident in cannabis, opiate, and amphetamine users.

CONCLUSIONS

Most users dependent on illicit substances experience psychotic symptoms in the context of use of, or withdrawal from, these substances. Psychotic symptoms increased with the severity of the substance use disorders for all 4 substances. These findings emphasize the importance of developing services to target this population as they are at a heightened risk for developing psychotic symptoms.

Amphetamines for schizophrenia

BACKGROUND

It is estimated that between 10% and 65% of people with schizophrenia use illicit drugs such as amphetamines. This group have an increased rate of hospitalisation, homelessness, unemployment and suicide compared with those with schizophrenia who do not abuse drugs.

OBJECTIVES

To evaluate the effects of amphetamines for people with schizophrenia in terms of clinically meaningful outcomes, cognitive functioning and physiological tests.

SEARCH STRATEGY

We searched the Cochrane Schizophrenia Group's Register (February 2002).

SELECTION CRITERIA

We included all randomised controlled trials investigating the effects of amphetamines on people with schizophrenia, compared with a placebo intervention.

DATA COLLECTION AND ANALYSIS

Working independently, we selected and critically appraised studies, extracted data and analysed on an intention-to-treat basis. Where possible and appropriate we calculated risk ratios (RR) and their 95% confidence intervals (CI), with the number needed to treat (NNT). For continuous data we calculated Weighted Mean Differences (WMD).

MAIN RESULTS

We included four short studies with a total of 83 participants. Data were few and poorly reported. The results indicated a reduction of negative symptoms for people allocated to amphetamines (n = 16, 1 RCT, WMD -3 CI -5.02 to -0.98). No such effect was found for positive symptom change (n = 16, 1 RCT, WMD 0 CI -4.46 to 4.46). Compared with placebo, amphetamines significantly increased metabolism in the left and right cerebellum (n = 23, 1 RCT, WMD 0.12 CI 0.06 to 0.18; n = 23 1 RCT, WMD 0.12 CI 0.06 to 0.18) and left striatum (n = 23, 1 RCT, WMD 0.14 CI 0.00 to 0.28) and also significantly decreased metabolism in the left dorsolateral prefrontal cortex (n = 23, 1 RCT, WMD -0.09 CI -0.17 to -0.01).

REVIEWERS' CONCLUSIONS

Understandably amphetamines are rarely formally evaluated in randomised studies and therefore unpublished work in this area is likely to exist. Addition of more studies may clarify reasons why people with schizophrenia persist in taking these harmful stimulants.

Stimulant psychosis: systematic review

BACKGROUND

Psychosis associated with stimulant use is an increasing problem, but there is little research evidence about the nature of the problem and its management.

AIMS

To critically review the literature on stimulant psychosis and sensitisation.

METHOD

Systematic review of studies that have investigated stimulant use and psychosis in humans. The main outcome measures were increases in psychosis with stimulant use, and differences between stimulant users and non-users.

RESULTS

Fifty-four studies met the inclusion criteria. Experimental studies show that a single dose of a stimulant drug can produce a brief increase in psychosis ratings (a "response") in 50-70% of participants with schizophrenia and pre-existing acute psychotic symptoms, unaffected by the presence of antipsychotic medication. Those with schizophrenia who do not have acute psychotic symptoms respond, but less frequently (30%). There has been little research into the longer-term effects of use.

CONCLUSIONS

Compliance with antipsychotic medication by someone with schizophrenia will not prevent a relapse or worsening of psychotic symptoms if stimulants are used. Low-dose antipsychotic treatment may be beneficial in stimulant users, to prevent sensitisation.

MRI correlates of treatment response in first episode psychosis

It is not known whether the magnitude of the structural brain abnormalities that underlie schizophrenia is a determinant of the extent to which patients respond to antipsychotic medication. This study was undertaken in order to explore this relationship. Twenty-six patients receiving treatment for a first episode of psychosis were involved in both a study measuring treatment response and a magnetic resonance imaging (MRI) study. In the treatment study, haloperidol dose was increased weekly beginning at 2 mg/day until patients showed evidence of a response or extrapyramidal symptoms. MRI scans were analyzed using a computerized volumetric approach to yield estimates of cerebrospinal fluid (CSF), gray-matter and white-matter volumes. Improvement in positive and negative symptoms after 1 week of treatment was significantly correlated with cortical gray-matter volumes. Those patients who were maintained on 2 mg/day of haloperidol had greater cortical gray-matter volume than those who were treated with higher doses. The severity of structural brain abnormalities at the onset of psychosis may contribute to individual variation in response to antipsychotic medication. It remains to be determined whether the degree to which particular domains of symptomatology can improve is related to the severity of structural brain pathology in specific brain regions.

A placebo-controlled trial of selegiline (L-deprenyl) in the treatment of tardive dyskinesia

The goal of this study was to determine whether selegiline (L-deprenyl), a selective monoamine oxidase B inhibitor and antioxidant, would improve neuroleptic-induced tardive dyskinesia (TD). Thirty-three patients with TD were randomly assigned to selegiline 10 mg/day or placebo for 6 weeks and were assessed at baseline and at weeks 1, 2, 4, and 6 for TD, parkinsonism, akathisia, depression, and positive and negative symptoms. Examinations for TD were videotaped and scored by a rater unaware of the temporal sequence of examination. Twenty-eight subjects completed at least 1 week of treatment; all five dropouts were receiving selegiline. When baseline score and gender were controlled, the group receiving selegiline displayed significantly less improvement of TD compared with the placebo group. The two treatment groups did not differ in any other outcome measure. Selegiline was less effective than placebo in reducing symptoms of TD over a 6-week trial. This may be the result of the dopamine agonist effects associated with selegiline.

Prefrontal sulcal prominence is inversely related to response to clozapine in schizophrenia

The object of this study was to determine if brain computed tomography (CT) scan measures are related to treatment response to clozapine, an atypical antipsychotic drug that is effective in some therapy-resistant schizophrenic patients. Thirty-four therapy-resistant patients were evaluated with the Brief Psychiatric Rating Scale (BPRS) before and after 6 weeks of treatment with clozapine. The patients were classified into Nonresponders, Moderate Responders, and Good Responders based on the percent change in BPRS. Comparison of these groups on prefrontal sulcal prominence (PSP) indicated a statistically significant linear trend, with nonresponders having the highest, moderate responders an intermediate degree, and good responders the least PSP. There were no linear trends for the ventricular-brain ratio (VBR), and no quadratic trends for either brain measure. A similar linear trend relating PSP to four of five BPRS subscales, including both positive and negative symptoms, was observed. The relationship between PSP and treatment response was also assessed with multiple linear regression, and PSP significantly contributed to prediction of BPRS at 6 weeks. The results are discussed with regards to the hypothesis that the effect of clozapine on psychopathology depends on prefrontal cortical function.