Something out of nothing: the placebo effect

The Canadian Network for Mood and Anxiety Treatments (CANMAT) Task Force Report: Serotonergic Psychedelic Treatments for Major Depressive Disorder

OBJECTIVE

Serotonergic psychedelics are re-emerging as potential novel treatments for several psychiatric disorders including major depressive disorder. The Canadian Network for Mood and Anxiety Treatments (CANMAT) convened a task force to review the evidence and provide a consensus recommendation for the clinical use of psychedelic treatments for major depressive disorder.

METHODS

A systematic review was conducted to identify contemporary clinical trials of serotonergic psychedelics for the treatment of major depressive disorder and cancer-related depression. Studies published between January 1990 and July 2021 were identified using combinations of search terms, inspection of bibliographies and review of other psychedelic reviews and consensus statements. The levels of evidence for efficacy were graded according to the Canadian Network for Mood and Anxiety Treatments criteria.

RESULTS

Only psilocybin and ayahuasca have contemporary clinical trials evaluating antidepressant effects. Two pilot studies showed preliminary positive effects of single-dose ayahuasca for treatment-resistant depression (Level 3 evidence). Small randomized controlled trials of psilocybin combined with psychotherapy showed superiority to waitlist controls and comparable efficacy and safety to an active comparator (escitalopram with supportive psychotherapy) in major depressive disorder, with additional randomized controlled trials showing efficacy specifically in cancer-related depression (Level 3 evidence). There was only one open-label trial of psilocybin in treatment-resistant unipolar depression (Level 4 evidence). Small sample sizes and functional unblinding were major limitations in all studies. Adverse events associated with psychedelics, including psychological (e.g., psychotomimetic effects) and physical (e.g., nausea, emesis and headaches) effects, were generally transient.

CONCLUSIONS

There is currently only low-level evidence to support the efficacy and safety of psychedelics for major depressive disorder. In Canada, as of 2022, psilocybin remains an experimental option that is only available through clinical trials or the special access program. As such, Canadian Network for Mood and Anxiety Treatments considers psilocybin an experimental treatment and recommends its use primarily within clinical trials, or, less commonly, through the special access program in rare, special circumstances.

Risperidone versus placebo for schizophrenia

BACKGROUND

Risperidone is the first new-generation antipsychotic drug made available in the market in its generic form.

OBJECTIVES

To determine the clinical effects, safety and cost-effectiveness of risperidone compared with placebo for treating schizophrenia.

SEARCH METHODS

On 19th October 2015, we searched the Cochrane Schizophrenia Group Trials Register, which is based on regular searches of CINAHL, BIOSIS, AMED, EMBASE, PubMed, MEDLINE, PsycINFO, and registries of clinical trials. We checked the references of all included studies and contacted industry and authors of included studies for relevant studies and data.

SELECTION CRITERIA

Randomised clinical trials (RCTs) comparing oral risperidone with placebo treatments for people with schizophrenia and/or schizophrenia-like psychoses.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened studies, assessed the risk of bias of included studies and extracted data. For dichotomous data, we calculated the risk ratio (RR), and the 95% confidence interval (CI) on an intention-to-treat basis. For continuous data, we calculated mean differences (MD) and the 95% CI. We created a 'Summary of findings table' using GRADE (Grading of Recommendations Assessment, Development and Evaluation).

MAIN RESULTS

The review includes 15 studies (N = 2428). Risk of selection bias is unclear in most of the studies, especially concerning allocation concealment. Other areas of risk such as missing data and selective reporting also caused some concern, although not affected on the direction of effect of our primary outcome, as demonstrated by sensitivity analysis. Many of the included trials have industry sponsorship of involvement. Nonetheless, generally people in the risperidone group are more likely to achieve a significant clinical improvement in mental state (6 RCTs, N = 864, RR 0.64, CI 0.52 to 0.78, very low-quality evidence). The effect withstood, even when three studies with >50% attrition rate were removed from the analysis (3 RCTs, N = 589, RR 0.77, CI 0.67 to 0.88). Participants receiving placebo were less likely to have a clinically significant improvement on Clinical Global Impression scale (CGI) than those receiving risperidone (4 RCTs, N = 594, RR 0.69, CI 0.57 to 0.83, very low-quality evidence). Overall, the risperidone group was 31% less likely to leave early compared to placebo group (12 RCTs, N = 2261, RR 0.69, 95% CI 0.62 to 0.78, low-quality evidence), but Incidence of significant extrapyramidal side effect was more likely to occur in the risperidone group (7 RCTs, N = 1511, RR 1.56, 95% CI 1.13 to 2.15, very low-quality evidence).When risperidone and placebo were augmented with clozapine, there is no significant differences between groups for clinical response as defined by a less than 20% reduction in PANSS/BPRS scores (2 RCTs, N = 98, RR 1.15, 95% CI 0.93 to 1.42, low-quality evidence) and attrition (leaving the study early for any reason) (3 RCTs, N = 167, RR 1.13, 95% CI 0.53 to 2.42, low quality evidence). One study measured clinically significant responses using the CGI, no effect was evident (1 RCT, N = 68, RR 1.12 95% CI 0.87 to 1.44, low quality evidence). No data were available for extrapyramidal adverse effects.

AUTHORS' CONCLUSIONS

Based on low quality evidence, risperidone appears to be benefitial in improving mental state compared with placebo, but it also causes more adverse events. Eight out of the 15 included trials were funded by pharmaceutical companies. The currently available evidence isvery low to low quality.

Zuclopenthixol versus placebo for schizophrenia

BACKGROUND

Zuclopenthixol is an older antipsychotic that has three distinct formulations (zuclopenthixol dihydrochloride, zuclopenthixol acetate or Acuphase and zuclopenthixol decanoate). Although it has been in common use for many years no previous systematic review of its efficacy compared to placebo in schizophrenia has been undertaken.

OBJECTIVES

To evaluate the effectiveness of all formulations of zuclopenthixol when compared with a placebo in schizophrenia.

SEARCH METHODS

On 6 November 2013 and 20 October 2015, we searched the Cochrane Schizophrenia Group Trials Register, which is based on regular searches of MEDLINE, EMBASE, CINAHL, BIOSIS, AMED, PubMed, PsycINFO, and registries of clinical trials. We also checked the references of all included studies and contacted authors of included studies for relevant studies and data.

SELECTION CRITERIA

We included all randomised controlled trials comparing zuclopenthixol of any form with placebo for treatment of schizophrenia or schizophrenia-like psychoses.

DATA COLLECTION AND ANALYSIS

We extracted and cross-checked data independently. We identified only a small number of studies so we cross checked all studies. We calculated fixed-effect relative risks (RR) and 95% confidence intervals (CI) for dichotomous data. We analysed by intention-to-treat. Where possible we converted continuous outcomes into dichotomous outcomes. When this was not possible we used mean differences (MD) for continuous variables. We assessed risk of bias for included studies and used GRADE (Grading of Recommendations Assessment, Development and Evaluation) to create a 'Summary of findings' table.

MAIN RESULTS

Only two studies, with a total of 65 participants, were eligible for inclusion in the review. Overall the quality of the two studies was low, with small study populations and significant sources of bias, so we were not able to use all the data in our comparisons. . The studies were old from 1968 and 1972, and would be unlikely to pass modern peer review standard. We were only able to find short-term data and only trials randomising zuclopenthixol dihydrochloride. We also hoped to identify data for zuclopenthixol acetate versus placebo and zuclopenthixol decanoate versus placebo comparisons. We were unable to identify any studies that included data on these two fairly widely used drugs.For our primary outcome of interest, clinically significant improvement, we found one study that provided useable data. Global state measured by clinical global impression scale (CGI) improvement showed different ratings when assessed by a psychiatrist or a nurse.The psychiatrist scores failed to achieve statistical significance, however when assessed by nursing staff, the difference favouring zuclopenthixol did reach statistical significance (1 RCT n = 29, RR 2.57 95% CI 1.06 to 6.20, very low quality data). There was also evidence of increased sedation with those treated with zuclopenthixol when compared with placebo (1 RCT n = 29, RR 4.67 95% CI 1.23 to 17.68, very low quality data). 'Leaving the study early' data were equivocal. No useable data were available for outcomes such as relapse, mental state, death, quality of life, service use or economic costs.

AUTHORS' CONCLUSIONS

For people with schizophrenia this review shows that zuclopenthixol dihydrochloride may help with the symptoms of schizophrenia. The review provides some trial evidence that, if taking zuclopenthixol dihydrochloride, people may experience some adverse effects and sedation compared with placebo. However this evidence is of very low quality and with some significant sources of bias. There are no data for zuclopenthixol decanoate or zuclopenthixol acetate.For clinicians, the available trial data on the absolute effectiveness of zuclopenthixol dihydrochloride do support its use but the limited nature of the data and significant sources of bias make conclusions hard to draw. Zuclopenthixol in all three forms is a commonly used antipsychotic and it is disappointing that there are so few data regarding its use.

Central nervous system influences in asthma

Asthma is a biomedical disorder whose presentation can be markedly influenced by neurological and psychological factors. This chapter describes several approaches that provide insight into the role of psychological factors and brain function in asthma. These include the study of placebo responses and recent explorations using functional neuroimaging during the onset of asthma symptoms. Although the specific mechanisms involved remain uncertain, we are gaining an appreciation for some of the neurocircuitry that is involved. The insula and ACC may modulate inflammatory processes by their influence on neuroendocrine responses to stress, including highly studied effects on the HPA axis and its physiologic responses. However much we have recently learned, it is clear that further study of this topic is critical to fully explicate the role of the brain in asthma.

Can attention control conditions have detrimental effects on behavioral medicine randomized trials?

OBJECTIVE

Attention control (AC) conditions are used to balance nonspecific attention in randomized trials of behavioral interventions. Very little guidance about which behavioral interventions and outcomes merit AC is available in the literature. The primary aim of the present study is to demonstrate a scenario in which use of AC in a behavioral randomized trial was unnecessary and possibly detrimental.

METHODS

Exploratory analyses were performed in a randomized controlled trial that tested whether a patient-centered counseling intervention reduced low-density lipoprotein cholesterol levels in 355 participants with peripheral arterial disease, compared with AC and usual care (UC) conditions. The patient-centered counseling intervention was designed to activate participants to ask their physician for lipid-lowering medication and/or increase dose intensity, increase medication adherence, and reduce fat intake. The AC condition involved attention-matched telephone-delivered health education, and the UC condition consisted of an educational pamphlet.

RESULTS

At 12-month follow-up, the mean low-density lipoprotein cholesterol changes were -11.1 and -6.8 mg/dL in the UC and AC conditions, respectively (p=.17). The proportion of participants who increased the use or dose intensity of medication was significantly lower in AC than in UC: 17.5% versus 30.5% (p=.03). No significant difference in other outcomes was observed between AC and UC.

CONCLUSIONS

AC has significantly worse medication outcomes, and there is no indication of a therapeutic effect on other end points. Implications for the use of AC in behavioral randomized trials are discussed.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00217919.

Philosophy matters in brain matters

PURPOSE

Although most neuroscientists and physicians would argue against Cartesian dualism, Descartes's version of the psyche/soma divide, which has been controversial since he proposed it in the seventeenth century, continues to haunt contemporary neurological diagnoses through terms such as functional, organic, and psychogenic. Drawing on my own experiences as a person with medically unexplained seizures, I ask what this language actually means if all human experience has an organic basis.

METHODS

Close reading of a textbook chapter on psychogenic seizures.

RESULTS

I expose the author's unreflective embrace of psyche and soma as distinct entities, his inherent bias against illnesses labeled psychogenic, and the implicit sexism of his position. I further argue that even when a patient's symptoms are not alleviated, heightened self-consciousness and narrative framing can strengthen his or her sense of agency and have therapeutic benefits.

CONCLUSION

The ethical treatment of patients requires a respect for their stories.

Complementary and alternative medicine: Exploring the gap between evidence and usage

Debates over the efficacy of complementary and alternative medicine (CAM) are highly polarized and have received much publicity of late. While ‘believers’ in CAM campaign for its integration into the NHS, ‘sceptics’ call for the withdrawal of any public funding for such services. These debates take place in the context of a steady rise in CAM usage both in the UK and abroad. Critics of CAM often point to the lack of scientific evidence demonstrating its efficacy. The lack of evidence gathered by means of randomized controlled trials is often used to make the claim that CAM is no more effective than placebo. This article examines some of the debates surrounding the use of evidence-based medicine to assess the efficacy of CAM. It also explores a number of issues pertaining to CAM and the placebo response including the moral questions surrounding the knowing use of placebo as therapy. The rest of the article presents material from a qualitative study carried out in northern England on the understandings of CAM efficacy. The material shows that CAM therapists and patients do not reflect the polarities evident in the public debate in their own understanding and usage of CAM. Rather they are pragmatic pluralists with clear ideas about when CAM treatment is appropriate and often have sophisticated insights into the placebo response. The article concludes with a brief discussion of the implications of these findings for future work in the growing field of CAM research.

Risperidone versus placebo for schizophrenia

BACKGROUND

Risperidone is the first new generation antipsychotic drug made available in the market in its generic form.

OBJECTIVES

To examine the clinical effects of oral risperidone for people with schizophrenia and schizophrenia-like psychoses in comparison with placebo.

SEARCH STRATEGY

We searched the Cochrane Schizophrenia Group's Register (February 2008), references of all included studies, and contacted industry and authors of included studies for relevant studies and data.

SELECTION CRITERIA

Randomised clinical trials comparing oral risperidone with placebo treatments for people with schizophrenia and/or schizophrenia-like psychoses.

DATA COLLECTION AND ANALYSIS

Two reviewers independently inspected citations and/or abstracts, ordered papers, re-inspected and assessed the quality of results and extracted data. For dichotomous data, we calculated the relative risk (RR), the 95% confidence interval (CI) and, where appropriate, the number needed to treat (NNT), on an intention-to-treat basis. For continuous data, we calculated weighted mean differences (WMD).

MAIN RESULTS

One study (n=599) compared risperidone against placebo but the attrition rate was 60% over a period of six weeks rendering most of the efficacy and global improvement data unusable. The attrition rate was higher for placebo compared with risperidone (n=1363, 10 RCTs, RR 0.70 CI 0.57 to 0.86, NNT 13 CI 9 to 29) and less participants left the trial in the risperidone arm due to lack of efficacy (n=888, 5 RCTs, RR 0.38 CI 0.20 to 0.73, NNT 7 CI 5 to 15). Risperidone was no better than placebo on the CGI global score (n=397, 3 RCTs, RR 0.80 CI 0.55 to 1.15) but significantly more number of participants in risperidone arm had more than 20% reduction in their BPRS/PANSS score (n=856, 7 RCTs, RR 0.43 CI 0.32 to 0.58, NNT 7 CI 6 to 10). Data became considerably more homogeneous (and positive) when the one study independent of industry funding was removed (I(2) 75% to 55%). Despite poor reporting, it is clear that around 24% of all participants receiving either risperidone or placebo developed some form of extrapyramidal effects (n=723, 5 RCTs, RR 1.40 CI 0.93 to 2.10). Three people on risperidone had prolonged QTc (n=198, 1 RCT, RR 7.5 CI 0.4 to 144), more on risperidone gained weight (n=303, 2 RCTs, RR 5.14 CI 1.79 to 14.73, NNH 10 CI 3 to 51) and had a raised prolactin (n=323, 2 RCTs, RR 12.54 CI 5.11 to 30.79, NNH 3 CI 2 to 5). Fewer in the risperidone arm needed an additional psychotropic during the trial period (n=186, 1 RCT, RR 0.62 CI 0.45 to 0.85, NNT 10 CI 7 to 28).

AUTHORS' CONCLUSIONS

Risperidone appears to have a marginal benefit in terms of clinical improvement compared with placebo in the first few weeks of treatment but data are limited, poorly reported and probably biased in favour of risperidone. The margin of improvement chosen by the researchers as their outcome may not be clinically meaningful. Even after so much use of this drug, we feel that further independent trials can be justified.

Acupuncture: what underlies needle administration?

Acupuncture is an ancient Chinese therapy with its mode of action unclear and efficacy inconclusive. A lack of attention given to the role of psychosocial context presented in clinical provision of acupuncture may mainly account for the current dilemma in acupuncture research. This psychosocial context induces various cognitive and affective processes in the patient while receiving this treatment. On the basis of the analysis of these psychological factors involved in clinical provision of acupuncture and in light of prior studies on the placebo effect, the author hypothesizes that acupuncture works through potentiation and modulation of a highly organized and somatotopic network of endogenous opioids that links expectation, attention and body schema. This hypothesis, which focuses on the contextual factors involved in clinical provision of acupuncture, has immediate clinical and experimental implications and will take the acupuncture debate much further forward.

A systematic review comparing the functional neuroanatomy of patients with depression who respond to placebo to those who recover spontaneously: is there a biological basis for the placebo effect in depression?

BACKGROUND

Functional neuroimaging research indicates that depression, and treatment, are associated with neurobiological changes. Changes associated with natural recovery or the placebo effect are unknown. The aim of this study is to assess whether the placebo effect in depression is associated with specific functional neuroimaging changes.

METHOD

Systematic review of functional neuroimaging studies containing unipolar depressed patients. Subjects were either: in a placebo group, undergoing pre- and post-treatment scans and clinical ratings; or were treatment-free, and underwent two sets of scans and ratings.

RESULTS

Of placebo group studies, 2 of 4 showed no specific changes; the others showed increased frontal activity on recovery. Of treatment-free studies, only 2 out 5 had sufficient relevance; both showed increased anterior cingulate activity on recovery, one showed increased left DLPFC activity.

LIMITATIONS

Methodological problems affected most of the studies found: low sample sizes, high inter-subject variability, and lack of design and data description for the question being asked in this review. There are limitations in comparing studies that differ in: subject type, neuroimaging technique, target site, trial design, and results. The fact that this systematic review was conducted by only one rater increases likelihood of bias.

CONCLUSIONS

Recovery from depression in placebo groups correlates with changes in frontal and cingulate cortical activity, although these may also be found in recovery without treatment. It is also speculated that antidepressant treatment delay relates to 'counterbalancing' of an advantageous placebo effect with a disadvantageous initial drug effect.