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Abstract
Objectives Incentives have been effectively used in several healthcare contexts. This systematic review aimed to ascertain whether incentives can improve antipsychotic adherence, what ethical and practical issues arise and whether existing evidence resolves these issues.
Design Systematic review of MEDLINE, EMBASE and PsycINFO. Searches on 13 January 2021 (no start date) found papers on incentives for antipsychotics. Randomised controlled trials (RCTs), cohort studies, qualitative research and ethical analyses were included. Papers measuring impact on adherence were synthesised, then a typology of ethical and policy issues was compiled, finally the empirical literature was compared with this typology to describe current evidence and identify remaining research questions.
Results 26 papers were included. 2 RCTs used contingent financial incentives for long-acting injectable antipsychotic preparations. Over 12 months, there were significantly larger increases in adherence among the intervention groups versus control groups in both RCTs. There were no consistently positive secondary outcomes. 39 ethical and practical issues were identified. 12 of these are amenable to empirical study but have not been researched and for 7 the current evidence is mixed.
Conclusions In keeping with other areas of healthcare, antipsychotic adherence can be increased with financial incentives. Payments of 2.5 times minimum wage changed behaviour. The typology of issues reported in this systematic review provides a template for future policy and ethical analysis. The persistence of the effect and the impact of incentives on intrinsic motivation require further research.
PROSPERO registration number CRD42020222702.
- ethics (see Medical Ethics)
- health policy
- mental health
- schizophrenia & psychotic disorders
- adult psychiatry
Data availability statement
All data relevant to the study are included in the article or uploaded as online supplemental information. All data is presented in online supplemental information.
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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- ethics (see Medical Ethics)
- health policy
- mental health
- schizophrenia & psychotic disorders
- adult psychiatry
Strengths and limitations of this study
A large number of papers were included.
Diverse methodologies have been synthesised to enable in-depth analysis of incentives for antipsychotics.
Meta-analysis was not possible as a too few randomised controlled trials were identified.
All objections were taken at face value, rather than subjected to philosophical analysis, so weak objections may have been included.
Background
Some people prescribed medications do not take them. Indeed, this is the case for antipsychotics. Incentives may overcome this reluctance, but would have extensive ramifications for patients, healthcare workers, and health systems. Adherence to antipsychotic treatment entails taking oral preparations or accepting injectable preparations as they are prescribed. A systematic review of patients with schizophrenia and bipolar affective disorder found that on subjective measures antipsychotic adherence ranges from 60% to 81%.1 Poor adherence often means undertreatment of psychotic illness.
Interventions have been designed to improve adherence to antipsychotics. Approaches such as adherence therapy and family therapy have had mixed results.2 There is tentative evidence that eHealth technologies such as SMS reminders and smart pill containers may improve adherence to oral antipsychotics.3 4Depot preparations offer another means of increasing antipsychotic adherence as treatment events are less frequent and covert non-adherence is prevented. Earlier systematic reviews found that depot treatment did not increase adherence compared with oral treatment and that there was no difference in relapse rates in randomised controlled trials (RCTs) comparing long-acting injectable to oral preparations.5 6 Cohort studies have, however, provided evidence supporting the use of long-acting injectable antipsychotics to prevent relapse and hospitalisation.7 8 A more recent systematic review incorporating cohort studies and pre–post studies in addition to RCTs, indicated that long-acting injectable antipsychotics are consistently more favourable in reducing risk of relapse or hospitalisation when compared with oral antipsychotics.9 For some individuals stabilised on depot treatment, however, relapse has been associated with side effects such as tardive dyskinesia and functional decline.10 Consistently improving adherence to antipsychotics may reduce relapse so other interventions to increase adherence should be considered.
Incentives may improve health behaviours including medication adherence.11 Financial incentives have been used in a wide range of healthcare settings: asthma, diabetes, HIV, weight loss and smoking cessation.12–16 A systematic review of 16 RCTs found that incentives were around 1.5–2.5 times more effective than other interventions at promoting a range of health behaviours.16 Other studies of financial incentives have found no effect or even negative effects.13 Incentives can be designed with a guaranteed sum or a lottery.17 They may motivate participants with the possibility of financial gains or the risk of loss.18 Rewards may be vouchers or cash, magnitudes vary and arrangements may change over the course of the intervention.19 20 Either the healthy behaviour or the healthy outcome can be rewarded.21
Governments around the world are interested in using incentives to improve health. The UK government recently announced plans for an Office for Health Improvement and Disparities, aiming to replicate the success of the Singaporean Health Promotion Board which has used financial incentives to increase behaviours including exercise and healthy eating.22 Unlike the Health Promotion Board, the UK’s Office for Health Improvement and Disparities will have a special remit for promoting mental health, suggesting financial incentives could enter mainstream mental healthcare in the UK over coming years.
Antipsychotic pharmacotherapy is an area where financial incentives are worth considering, not least because of the limited success of other interventions to improve adherence to antipsychotics.23 Much of the research into financial incentives in mental healthcare has examined positive financial incentives for substance abuse,24 25 although there have been small studies exploring treatment of other conditions such as depression.26 Antipsychotics are the mainstay of treatment for schizophrenia, a chronic condition with a lifetime morbid risk of 7.2 per 1000 and a median age of onset in the mid-20s.27 28 Preventing psychotic relapse should be a policy priority because of its human and health economic cost. Annually, 35.8 people are hospitalised with psychosis per 100 000 population and the cost of relapse is estimated at tens of thousands of dollars.29 30 However, it is important that ethical and public policy issues are also taken into consideration beyond any mental health benefits of incentives.
Whether an incentive changes behaviour is best ascertained with RCTs. Appraising whether an incentive improves care in the complex setting of mental health provision entails considering the whole biopsychosocial programme of care including its impact on relapse risk, relationships, other patients, staff and the wider health system.
Aims
This systematic review aims to investigate how far current evidence supports a policy of using incentives to increase antipsychotic adherence. Specifically, the paper asks three questions:
Do incentives improve antipsychotic adherence?
What are the potential ethical and practical issues in offering incentives for antipsychotic adherence?
Does existing evidence clarify any ethical and practical issues identified?
Material and methods
Search strategy and selection criteria
Search strategy
A systematic search of heterogeneous research was performed by NH and MM. MEDLINE, EMBASE and PsycINFO were searched for papers addressing financial or non-financial incentives in antipsychotics. Searches included a term related to antipsychotics and a term related to incentives (see online supplemental file 1). References were screened. RCTs and observational studies were included per the protocol; qualitative research and ethical analyses were also included because they covered perspectives which would otherwise be missed. Papers published up to 13 January 2021 were included. There was no start date. Trials in populations aged under 18 or over 70 were excluded to avoid compounding any ethical objections to financial incentives. No articles were translated and it was not necessary to contact study authors. The protocol adheres to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Enhancing transparency in reporting the synthesis of qualitative research (ENTREQ) statements (see online supplemental file 2 and 3).
Supplemental material
Study selection
Searches were carried out on 13 January 2021. Search results were stored on Healthcare Databases Advanced Search (HDAS) and duplicates were removed automatically. (Population, Intervention, Comparison, Outcomes and Study Design (PICOS) table given in online supplemental file 4). Further deduplication was carried out by NH. Remaining studies were screened by title and abstract by both NH and MM. All disagreements were discussed and resolved. Each paper was read in full and data extraction was carried out by NH and MM. Data extraction varied by paper type. The Joanna Briggs Critical Appraisal Tools for Qualitative Research, Economic Analysis, RCTs, and Text and Opinion were used to assess the quality of the methodology sections of the relevant included papers.31
Analysis
Results were analysed sequentially by paper type. It was anticipated that evidence regarding implementation would include a diverse range of papers and accordingly a narrative synthesis was planned following Popay et al’s methodology.32 A theory of change was developed by NH and SS building on the literature around present bias (see box 1). In phase 1, a preliminary synthesis of the impact of incentives on adherence was developed by NH through listing and tabulation. In phase 2, papers examining ethical, practical or conceptual considerations were analysed. Inductive thematic analysis was conducted by NH and MM. The coding framework drew on the four principles of medical ethics, plus an additional topic ‘consideration of relationships’, which is absent from Beauchamp and Childress’s model.33 This process generated a typology of ethical and practical issues. In phase 3, papers reporting experiences of patients and frontline staff were analysed by NH and MM. The typology of issues generated in phase two was used as a framework. The data from papers reporting the experiences of patients and frontline staff was analysed according to which practical and ethical issues were addressed. Any new issues emerging from these papers were added to the typology. Any evidence bearing on the practical and ethical issues was described. This generated a comprehensive list of issues in financial incentives for antipsychotics grouped by the current state of the evidence around this issue. The robustness of the synthesis was assessed discursively, drawing particularly on the critical appraisal of primary studies, their heterogeneity and strength of conclusions drawn. Critical appraisal was performed by NH. Pilot studies and protocols were not subjected to critical appraisal. Raw scores were reported.
Overview of theory of change
We use the standard economic assumption that people’s preferences have financial equivalents; most pleasant experiences have a maximum amount of money any given person would pay to experience it.71 72 This simply means that in general people would willingly accept a given unpleasant experience in exchange for a large sum of money but not a small sum of money, and it stands to reason that there is a cut-off point which represents the minimum amount of money a given person would be willing to accept to experience it. People also make trade-offs whereby pleasant experiences for which one would pay the same amount of money could be exchanged with one another, or where one accepts an unpleasant pleasant experience of a lesser equivalent value in order to gain a pleasant experience.73
These values can be estimated experimentally across groups. Although infrequently used in front-line healthcare, they provide a helpful way to think about patients’ preferences and choices. These values also allow bundles of qualitatively different goods to be combined and compared.
Under treatment as usual the decision whether or not to adhere to an antipsychotic can be modelled as a choice between option i and option ii. The values of the constituent parts of options i and ii can be given this way:
A + ∂Bu
A – D + ∂Bt
In this model, A is some level of baseline well-being, D balances out the cost of the discomfort and inconvenience caused by the depot treatment, or the equivalent payment they would accept to accept such an experience. B is the expected change in future utility which is influenced by whether mental illness is untreated (Bu) or treated (Bt). ∂ represents the time discount factor. People value future well-being less than they value present well-being and a great deal of evidence shows that immediate discomfort is often overweighted in decisions bearing on future well-being.74 75 If future utility is valued at 40% of present utility, then ∂ is 0.4. (As we only consider one future time point, we need not consider different models of discounting over time.)
This shows that under treatment as usual a rational actor would choose option ii if they expect Bu to exceed Bt by more than D after temporal discounting. One problem with this is that ∂ may be very small for people facing other immediate adversity which would give D excessive weight simply because it is experienced in the present.76
Linking an incentive to treatment augments this model:
A + ∂Bu
A+C – D + ∂Bt
In this model, the incentive (with an equivalent value of C) and the treatment occur immediately and future well-being is, as above, discounted. Now the rational actor would accept the depot antipsychotic if C cancels out D (less the discounted amount by which Bt exceeds Bu) after taking into account the different weighting of losses and gains described by prospect theory.61 That is, if the discomfort or inconvenience of the depot is smaller than the expected benefit of the treatment after temporal discounting plus the incentive.
Based on this model we believe contingent incentives can change behaviour. Whether or not other regimes of incentives can change behaviour would require more detailed consideration of the evidence. We doubt that patients generally believe that their long run well-being is harmed by antipsychotic treatment, but if they acknowledge only a small benefit and this is discounted by present bias then the immediate inconvenience and discomfort of adherence may outweigh adherence. We anticipate that the value of an immediate incentive could outweigh the immediate inconvenience and discomfort, meaning that many patients would change behaviour. We recognise that this model makes assumptions about rationality, effective organisation and functional prospective memory which may not apply to all patients under all circumstances.
Data extraction was preplanned for study type, number of participants in each arm, demographics, patient exclusion criteria, type of antipsychotic, mental disorders being treated, incentive regime, measure of adherence, adherence level, measure of clinical outcome and clinical outcomes. Additional extraction was performed for practical and ethical issues identified, economic outcomes, and experiences of patients and clinicians. Given the small number of RCTs specifically measuring change in adherence, our protocol dictated that meta-analysis was not performed. This systematic review was funded via NH and MM’s National Institute for Health and Care Research (NIHR) fellowships.
Patient and public involvement
Research papers reporting the experiences of people offered incentives were searched for, included and synthesised in this review. Few people have been offered incentives for adherence so formal involvement of the relevant group was not possible.
Results
General results
A total of 872 results were obtained through HDAS searches after deduplication. One additional paper was identified through references. 30 papers were assessed at full paper and 26 papers were included in the final analysis (see figure 1 and online supplemental file 5).4 34–58 All included papers addressed financial incentives; no papers discussed non-financial incentives. All papers studied depots including long-acting injectable preparations and weekly oral penfluridol for schizophrenia, schizoaffective disorder or bipolar affective disorder. Although our protocol stated that pilots would be excluded, two pilots were included because they also presented qualitative data.34 35 Ten included papers provided analysis but no new empirical data, among which were two RCT protocols.
PRISMA diagram. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.
Phase 1: change in adherence
Financial incentives for depot antipsychotic therapy have been implemented in five studies. In the UK and the Netherlands, there have been two pilot studies and two RCTs using immediate contingent incentives (as opposed to lotteries or deposit contracts).4 34–36 There is one short protocol for an ongoing and unpublished Canadian trial.37 Table 1 shows the characteristics of these studies. The results of the completed RCTs have been published across several papers so all high-quality evidence of efficacy comes from the FIAT trial and the Money for Medication (MfM) trial. Table 2 gives the similarities and differences between the participants in the RCTs. Both have quality scores of 9 out of 13, limited specifically by lack of blinding.
Published designs for implementation of financial incentives for depot antipsychotic treatment
Characteristics of FIAT and MfM participants
Table 3 compares data from the four implementations of financial incentives for antipsychotic depot therapy, illustrating baseline, intervention period and postintervention adherence where available. Over the 12 months of the FIAT trial and the MfM trial, the intervention groups’ adherence increased by 16 and 18 percentage points, respectively, and the control groups’ adherence only increased by 4 and 2 percentage points, respectively.4 36 Both these differences were statistically significant and support the hypothesis that incentives increase adherence. Pavlickova et al explored how the FIAT trial data varied over the four quarters of the trial period, revealing that adherence in both groups increased over time but that adherence in the intervention group was higher at all stages.39 This shows incentives are effective throughout the first 12 months.
Adherence at different time points across all programmes of financial incentives for depot antipsychotics
Results of follow-up differed between the trials. In the FIAT trial no difference was found between the intervention and control group after the incentives were withdrawn. From the final quarter of the intervention to the first 6 months after discontinuation of incentives the intervention group’s adherence fell from 90% to 70% and the control group’s adherence fell from 79% to 77%.38 The difference between 70% and 77% was not significant at the 0.05 level (p=0.078).38
The MfM study found that in the first 6 months after incentives were withdrawn adherence fell from 94.3% to 83.4% in the intervention group, and also fell from 80.3% to 76.0% in the control group. The difference between the two groups after the incentive was withdrawn was significant at the 0.05 level (p=0.047).36
The FIAT trial followed patients until 24 months after incentives were withdrawn. During this period, adherence fell in both groups to 68% and 74% in the intervention and control groups respectively (p=0.130).38 The consistent finding is that the incentives increase adherence while they are in place, but after they are withdrawn it is not clear whether the difference persists, disappears or even reverses.
Secondary outcomes from the RCTs revealed few significant differences. Both FIAT and MfM measured overall clinical state (FIAT through clinician global rating and MfM through the Positive and Negative Symptoms Scale (PANSS)), suicide attempts, psychiatric hospital admissions and quality of life with FIAT using a structured communication between patient and clinician (known as DIALOG) and MfM using Manchester Short Assessment of Quality of Life (MANSA).4 36 59 60 The MfM trial included measures of substance misuse (Composite International Diagnostic Interview (CIDI) and Addiction Severity Index (ASI) scores), psychosocial functioning (Health of the Nation Outcome Scale (HoNOS) total) and medication side effects (Acute Stress Checklist (ASC) scores). The FIAT trial measured criminal justice contact and violent incidents and also published follow-up 6 months and 24 months after the trial period ending describing suicide attempts, violent incidents and police arrests. Among these secondary outcomes almost all had insignificant results. The exception was that the FIAT trial’s DIALOG scores differed significantly (p=0.002) in favour of the intervention group, although the MANSA score in the MfM study did not differ (p=0.36).4
Phase 2: ethical and practical issues
The search identified 11 papers including 2 RCT protocols which analysed ethical and practical considerations in financial incentives and antipsychotics without using original data (see table 4).40–50 These papers are important because they interrogate concepts with a level of depth not possible in empirical research. All but one paper scored over 50% on the Joanna Briggs Institute critical appraisal.
Ethical issues and outstanding concerns identified in theoretical analysis papers
Table 4 shows the themes from these papers and indicates which theme they were assigned. A coding framework listing all the issues emerging from these papers was created (see online supplemental file 6). Themes connected to respect for autonomy ranged from risk of coercion (1.1) through to less restrictive option (1.6) and increase in autonomy (1.7). Beneficence covered elements of effectiveness including increasing adherence (2.1), limited flexibility (2.6) and who might benefit (2.4 and 2.6). Non-maleficence themes included a range of possible harms caused by incentives such as perverse incentives (3.1) and increased substance abuse (3.6) Only five themes were connected to justice and included fairness between patients (4.1 and 4.4), patients’ perception of fairness (4.2 and 4.5) and the risk of an exploitative power dynamic (4.3). Seven codes fell outside of the four principles and went beyond relational issues, covering abstract concepts such as dignity (5.1), intrinsic motivation (5.2), greed (5.4) and trust (5.6) as well practical implementation considerations (5.3, 5.5 and 5.7).
Phase 3: experience
Eight papers included data on the experience of staff and patients in their analysis of financial incentives (see online supplemental file 7).51–58 Throughout the pilots and trials of financial incentives, researchers studied the lived experience of relevant stakeholders. Early papers sought the perspectives of stakeholders on feasibility of and challenges around using financial incentives.51 52 Subsequent papers were able to explore the experience of patients and clinicians involved in trials of financial incentives either through qualitative research or through analysis of quality of life and motivation questionnaires.53–58 Two papers53 56 used validated tools to answer specific questions about the experience of participants while the others used unvalidated surveys or interviews.53 Among qualitative papers, quality varied greatly reflecting that some analyses were conducted ad hoc.
In combination with the papers reporting change in adherence, these papers shed light on the typology of themes identified in phase two. Table 5 details what is known about each issue.
A table describing any evidence supporting or opposing the established objections to the use of incentives for antipsychotic adherence
Six new themes also emerged from the experience data. There is a safeguarding risk of exploitation in the community when people received regular cash payments, which unless monitored could in turn have implications for consent. Whether or not quality of life improves is a relevant policy consideration. The possibility of using non-financial incentives emerged. Patients perceived an inherent benefit to having more money available and there was evidence that the idea of rewarding good behaviour was salient. Finally, researchers have also considered the risk that financial incentives impair insight.
Several of the themes raised had supporting evidence: better adherence, better efficacy of other treatments, risk of perverse incentives, having more money to spend, rewarding good behaviour and risk of exploitation. Meanwhile, there was evidence indicating several potential challenges had not materialised: financial dependence, forgetful patients, ineffectiveness, increased stigma, difficulty withdrawing incentives, reduced intrinsic motivation, fraud or demands for increased money, supplanting social networks or non-financial incentives being more appropriate.
Several topics require further research, some because existing evidence is mixed and some because there is no existing evidence. There was mixed evidence around habit formation, increased substance abuse, sense of entitlement, penalising good adherence, the impact on the clinician-patient relationship, quality of life and insight. Meanwhile there was no information regarding medication counselling, treatment personalisation, compliant patients’ attitudes, flexible payment arrangements, increased demand for medications, disinterest in adverse effects, inclusion criteria, links with other reinforcement techniques or changing payment levels. Importantly, there is no current evidence that hospitalisations reduce with financial incentives, meaning conclusions cannot be drawn regarding claims that incentives offer a less restrictive option or have better outcomes. In connection, the differences in healthcare system (and justice system) costs of financial incentives were not significant.57 58 The direct costs of financial incentives are small, costing hundreds of pounds per year, but the wider economic impact is unknown (see online supplemental file 8).
Finally, there were several domains which we did not believe could be definitively resolved with empirical data: coercion, disrespect for decisions, increased autonomy, exploitation of a power dynamic and patient dignity.
Discussion
Summary of results
In this systematic review, two RCTs provide moderate-quality evidence that patients with relatively low adherence will accept more depot antipsychotic doses when combined with financial incentives. There is no consistent evidence of improved secondary outcomes and it is unclear whether adherence is adversely impacted after withdrawal of incentives. An extensive typology of potential issues in financial incentives for antipsychotic adherence has been generated. This has been used to identify the questions which remain unanswered in financial incentives, including 12 areas which are suitable for empirical study where there is no current evidence, and 7 where the evidence is currently mixed.
Comparison with the literature
The finding of effectiveness is broadly in keeping with the literature on financial incentives. This supports our theory of change and indicates that setting the value of C at around £15 was sufficient to outweigh the discomfort and inconvenience of treatment (valued at D) after taking into account the different treatment of losses and gains.61 This reveals that most people who miss their antipsychotic depot do so not because of deeply held or fixed values, but for reasons which are easily outweighed by a small incentive. (Note that £15 was roughly 2.5 times the top rate national minimum wage in the UK in 2013. Today that figure would be about £22.)62 63 These findings should be taken into consideration in future ethical analyses of autonomy in this area.
The incentives were linked to a positive behaviour (depot acceptance) not a complex health outcome (such as not relapsing). Fryer found that incentive programmes were more effective when linked to actions rather than outputs.21 Indeed depot administration is well-suited for incentivisation because it is binary and easily monitored. Among oral psychiatric medications, the next appropriate area might be a tablet with routine monitoring of levels (such as clozapine or lithium). The studies included in this review also targeted patients with low adherence. This is in keeping with Mitchell et al’s finding that the effect of incentives on daily steps was more marked among adults with a low baseline.64
Whether the change in adherence persists remains uncertain. Some have argued that incentives erode intrinsic motivation such that the removal of incentives means target behaviour falls below baseline, but this review found some evidence of preserved intrinsic motivation. Others have argued that incentives can drive habituation meaning positive changes persist after withdrawal of incentives although a systematic review of incentives for exercise found post-intervention physical activity generally returned to baseline.11 65
Titmus proposed that paying people to give blood could theoretically reduce donations by ‘crowding out’ the intrinsic motivation and Frey and Oberholzer-Gee have shown that financial incentives crowded out motivation enough to reverse some people’s preferences, but in the context of healthcare there is a lack of clear evidence of crowding out.66 67 This systematic review found evidence that self-reported intrinsic motivation was not reduced by incentives, but the unclear results regarding post-intervention adherence leave open questions about whether revealed motivation may differ from reported motivation.67
Previous authors have been wary of financial incentives because of apparent ethical issues. This is in keeping with Promberger et al’s finding that members of the public generally felt health outcomes achieved through medication were more ethical than those achieved through financial incentives, although any reasoning behind this instinct was unclear and there is diverse evidence regarding the acceptability of financial incentives in healthcare.68 69 Halpern et al summarised five ethical issues regarding incentives in healthcare.70 The first was that they interfered with autonomy, but the authors argue that this is difficult to sustain given incentives do not close off any options to patients. In this study we have revealed a more complex relationship between incentives and autonomy, as incentives have improved many patients’ relationships with clinicians and have been viewed as a reward, not a constraint, by patients. The authors also suggested incentives could act as undue inducements, although this problem is unlikely in studies where each incentive is around £15. Similarly their fourth concern—monitoring invades privacy—was identified in this review but is irrelevant to depot treatment since covert non-adherence is impossible. Their third concern (crowding out) is actually a practical issue and has been addressed above. Finally there is a question of justice: why should those with low adherence be paid to do what other people do for free? This review has illuminated some relevant factors: few (but some) patients with good adherence complained about unfairness and nothing is known about the impact of incentives on high adherence patients. Given the low cost of incentives compared with the price of depots, future researchers should consider whether it is more efficient to reward those with good adherence as well. Altogether, this systematic review has bridged the ethical literature to the practical literature in order to identify which ethical issues remain outstanding, providing a template for future researchers exploring the ethics of financial incentives in this area.
Strengths and limitations
This review has taken an interdisciplinary approach. The authors include practising clinicians and behavioural scientists ensuring that the analysis has been informed by the realities of front-line practice and behavioural science research. It brings together a diverse set of evidence across 26 papers and is the first systematic review of financial incentives in the context of antipsychotic therapy. Studies using different methodologies and answering a range of research questions have been synthesised, providing a rich understanding of the intervention. This methodology has allowed us to advance the literature beyond the question of whether financial incentives increase antipsychotic depot adherence, by describing the relevant policy considerations and where conceptual issues remain unaddressed.
There have only been two published RCTs on financial incentives, the FIAT and MfM trials, and no meta-analysis has been performed. The other studies included in this systematic review were of mixed quality. The RCTs had low scores on critical appraisal tools because of a lack of blinding, but this did not impair external validity. However, some of the qualitative research was low quality due to a lack of preplanning and we would recommend that future studies embed qualitative assessment of acceptability in their protocol.
Another limitation is that in compiling a list of criticisms of financial incentives for antipsychotics we have not appraised whether these criticisms withstand rigorous theoretical analysis, rather comparing them with any available empirical data. This means our list of concerns may be overinclusive and may contain some weak criticisms. We identified several issues which we considered inappropriate for empirical study, but these conclusions could be proven wrong. Finally, we included pilot studies in this systematic review and both had positive results; this leaves the result open to publication bias but informal grey literature searches have failed to reveal any evidence of unpublished small studies with negative results.
Implications for clinicians, researchers and policy-makers
This review has generated a list of areas where further research is needed, some where the current evidence is mixed (such as substance abuse, entitlement to money, the clinician–patient relationship) and others where there is no evidence (whether incentives change medication consideration and counselling, how regimens can be altered or personalised and who should be included). It is also necessary to establish whether, on larger scale, financial incentives create a significant reduction in relapse and admission. If no reduction is identified, then it is important to ascertain whether that is because increased contact with services leads to more opportunities for admission, because of substance abuse, or because the wrong treatment is being used. This study failed to identify a knock-out ethical or practical argument against financial incentives for antipsychotic adherence, but ethicists should continue to explore how autonomy can be maximised where financial incentives are implemented.
We recommend that policymakers continue to pursue financial incentives as a viable means of helping patients improve their own mental health. This policy should involve larger studies of financial incentives for antipsychotic depots among low adherence patients with longer follow-up, and small studies including high adherence groups, different incentive magnitudes and daily tablet regimens. We have shown that, where implemented so far, financial incentives are an effective and acceptable way of increasing adherence to antipsychotics.
Data availability statement
All data relevant to the study are included in the article or uploaded as online supplemental information. All data is presented in online supplemental information.
Ethics statements
Patient consent for publication
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Footnotes
Twitter @nathanhodson
Contributors NH and SPS conceived and planned the review. NH and MM conducted searches and synthesised the literature. NH, IV and SPS analysed the results and wrote up the manuscript. SPS is the guarantor.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.