Perceived Barriers to Using Neurostimulation: A National Survey of Psychiatrists, Patients, Caregivers, and the General Public

Abstract

Objectives:

Neurostimulation interventions often face heightened barriers. The objective of this study is to examine different stakeholders perceived barriers to using different neurostimulation interventions for depression.

Methods:

We administered national surveys with an embedded experiment to 4 nationwide samples of psychiatrists (n=505), people diagnosed with depression (n=1050), caregivers of people with depression (n=1026), and members of the general public (n=1022). We randomly assigned respondents to one of 8 conditions using a full factorial experimental design: 4 neurostimulation modalities [ECT, rTMS, DBS, or adaptive brain implants (ABIs)] by 2 depression severity levels [moderate or severe]. We asked participants to rank from a list what they perceived as the top 3 barriers to using their assigned intervention. We analyzed the data with ANOVA and logistic regression.

Results:

Non-clinicians most frequently reported “limited evidence of the treatment’s effectiveness” and “lack of understanding of intervention” as their top 2 most important practical barriers to using ECT and TMS, respectively. Compared to non-clinicians, psychiatrists were more likely to identify “stigma about treatment” for ECT, and “lack of insurance coverage” for TMS, as the most important barrier.

Conclusion:

Overall, psychiatrists’ perceptions of the most important barriers to using neurostimulation interventions were significantly different than those of non-clinicians. Perceived barriers were significantly different for implantable (DBS and ABIs) versus non-implantable (rTMS and ECT) neurostimulation interventions. Better understanding of how these barriers vary by neurostimulation and stakeholder group could help us address structural and attitudinal barriers to effective use of these interventions.

1. Introduction

Barriers to seeking help and accessing treatment for major depressive disorder (MDD) are prevalent for the most common types of treatment, such as psychotherapy or pharmaceutical medication¹. Most mental healthcare is provided by primary care despite low levels of comfort with many of these treatments². These barriers prevent many patients from receiving needed treatment. Few studies have looked at barriers to access approved neurostimulation interventions, such as such as electroconvulsive therapy (ECT) and repetitive transcranial magnetic stimulation (rTMS), but there is some evidence to suggest that patients face even more barriers to accessing these type of interventions^3,4. Novel neurostimulation interventions, including deep brain stimulation (DBS) and adaptive brain implants (ABIs), are currently being investigated as possible treatments for depression. Given the need for neurosurgery with these interventions, barriers to their use are likely to be even greater.

Of the few quantitative studies assessing barriers to access neurostimulation for depression, the majority focus on ECT^5–8 and on psychiatrists’ perspectives. These studies have found that lack of knowledge about ECT itself and lack of trained physicians are key perceived barriers. One online survey study conducted in Turkey found that even physicians with training in ECT personally felt that they lacked knowledge about the therapy⁵. A study by Wilkinson and colleagues (2021) found similar results among US psychiatrists⁸. A survey conducted in the Netherlands found that psychiatrists believed patients to be unaware of ECT and other neurostimulation interventions for depression, leading to these treatments being underutilized⁷.

Another kind of barrier commonly identified in survey studies about these interventions involve access to the therapies. For example, van der Wurff et al. (2004) and Bilginer and Karadeniz (2019) found that psychiatrists perceived unavailability of the treatment as a major barrier to ECT^5,7. Further barriers limiting access are a lack of physical space for ECT equipment⁸), limited number of facilities that have the equipment necessary to perform ECT (in particular, outside of densely populated areas), outdated equipment, and a lack of staff with sufficient training for administering ECT^6,7. These factors mean that many patients would need to travel to a center offering ECT, which may not be possible for many.

Neurostimulation interventions also pose financial barriers such as out-of-pocket cost and insurance coverage^6,8. For example, ECT is an expensive service to provide and to pay for by patients, compared to the cost of most first-line treatments. In a series of interviews conducted by Cabrera et al. (2022), psychiatrists noted that insurance coverage was often a hurdle for receiving rTMS compared to other approved neurostimulation interventions⁹. While rTMS is covered by most major insurances, insurance criteria can vary by state and insurance carrier, creating additional barriers to access as insurance companies struggle to keep pace with the advancements in the field.

Beliefs about and attitudes toward neuromodulation can also create barriers to access. Although studies have demonstrated the efficacy and safety of ECT to treat depression, psychiatrists still identified both adverse side effects and stigma related to the treatment as barriers to its use^5,7,8,10 , leading to both fewer patients seeking it and fewer psychiatrists referring patients for treatment. Historically, ECT had been used punitively in some cases and the associated negative attitudes continue to influence public perceptions^11–13 . Furthermore, although contemporary ECT treatment is vastly safer now than previously due to changes in anesthetic practices and modifications in stimulus delivery, some psychiatrists hold negative perceptions of ECT⁷. rTMS remains largely unknown to the general public¹⁴, although its use is expanding to a growing number of neuropsychiatric conditions¹⁵, with novel devices approved, new protocols (e.g., different stimulation parameters) introduced, and combinations of TMS with brain imaging techniques.

When it comes to DBS and ABIs, only one survey study has looked at psychiatrists’ perceptions of barriers to treatment with DBS. Similar to results from ECT and rTMS studies, identified barriers for DBS included lack of knowledge about technical aspects of DBS, and resistance to the treatment from patients and family members¹⁶. Other barriers include lack of evidence for effectiveness and strict eligibility criteria¹⁶. While ABIs share many similarities with DBS from a technological and procedure point of view, there have been no survey studies examining barriers focused uniquely on ABI treatment.

This study aims to address current gaps in the literature by identifying perceived barriers to using neurostimulation interventions for MDD, by different modality (ECT, rTMS, DBS, ABIs) and across different stakeholder groups including patients, caregivers (individuals with experience caregiving for a family member or close friend with a psychiatric disorder), psychiatrists, and members of the general public. This study contributes to the existing literature by examining how different key stakeholders, including non-clinician stakeholders, perceive barriers to neurostimulation treatments for depression.

2. Methods

2.1. Study Design

We gathered data from a standardized survey with an embedded video vignette experiment that was administered online via Qualtrics to four large US samples including: the general public (n = 1022), caregivers [individuals with experience caregiving for a family member or close friend with a psychiatric disorder] (n = 1026), depressed patients (n = 1050), and board-certified psychiatrists (n = 505, out of 16,190 that we invited to participate) between April and June 2020.

After providing informed consent, participants answered preliminary questions and viewed a randomly assigned video vignette featuring professional actors playing a patient with MDD, with either moderate or severe depression receiving information about a neurostimulation intervention from her psychiatrist^17,18. Here we focus on the ranked order question about perceived barriers to accessing the intervention participants saw depicted in the vignette. Participants were asked to rank the three most important barriers from the following list: limited evidence of treatment effectiveness; lack of understanding of intervention; out-of-pocket cost; lack of insurance coverage; low public trust in mental health system; treatment is not available in all geographic areas; stigma about treatment; and frequency of treatment. Within the question, we randomized the item order to eliminate question order effects¹⁹. In addition, we measured six demographic, social, and political characteristics that we employed as controls in our statistical analyses. The exact wording for this survey question is located in the Supplemental Digital Content (SDC). The Michigan State University Institutional Review Board approved this study.

2.2. Participants

To draw our three non-clinician samples, we contracted with Qualtrics. For our general public and caregiver participants, Qualtrics drew quota samples from a panel of participants that matched US population estimates of age, sex, race, and income. For the caregiver stakeholder group, Qualtrics applied an additional screening question to ensure caregiver status in addition to the population estimate matching. For the patient stakeholder group, Qualtrics drew a quota sample from a different internet panel of adults who had previously reported having a depression diagnosis. Our patient sample also matched age, sex, and race estimates of the US adult population living with depression.

The research team managed the sampling and recruitment of the psychiatrist stakeholder group. We employed the Tailored Design Method to contact a national stratified random sample of US board-certifies psychiatrists, achieving a sample of 505 US psychiatrists who fully completed our survey¹⁹. Table 1 below displays key social and demographic characteristics for each of our four samples in this study.

Table 1:

Description of the Pooled Sample (N=3603)

	General Public (N=1022)	Caregivers (N=1026)	Depressed Patients (N=1050)	Psychiatrists (N=505)
Gender (% female)	50.9%	64.2%	73.7%	36.6%
Age (% aged 55+)	35.2%	21.9%	16.7%	60.4%
Race (% white)	78.0%	80.5%	88.7%	82.2%
Ethnicity (% Hispanic)	17.4%	13.2%	8.3%	5.7%
Education (% with bachelor’s degree)	45.2%	54.6%	33.3%	98.2%
Political Ideology (% liberal)	35.2%	40.0%	39.8%	63.6%
Religiosity (% monthly attendance)	35.0%	44.9%	30.9%	33.3%

2.3. Analytical Techniques

We ran a series of multiple logistic regression models to examine variation in the top ranked barriers by stakeholder group, intervention modality, and depression severity, while accounting for respondents’ demographic, social, and political characteristics. We modelled the main effects of the experimental factors (i.e., intervention modality and depression severity) and stakeholder group membership (i.e., psychiatrists, patients, caregivers, and members of the public) with dummy variables, with ECT modality, moderate depression, and psychiatrist group as the reference groups, respectively. To formally assess whether the influence of stakeholder group membership on perceived barriers is statistically moderated by modality or depression severity we included interaction terms in our multiple regression models. All analyses were conducted using IBM SPSS 26.0.

3. Results

Figure 1 shows the top three perceived barriers by stakeholder group and modality. The supplemental file includes the breakdown of the first, second and third choices.

Figure 1:

Panel of four quadrants, each quadrant shows a different neurostimulation intervention, and the proportion of participant in a given stakeholder group that ranked each potential barrier in the top 3.

Odds ratios from the multiple logistic regression results are presented in Table 2 and provide preliminary evidence that participants’ perceived barriers vary across stakeholder group and by modality.

Table 2:

Odds Ratios from Multiple Logistic Regression Models Explaining Top Perceived Practical Barriers to Use of PEIs across Key Stakeholder Groups (N=3603)

Predictors	Limited Evidence of PEI’s Effectiveness	Lack of Understanding of PEI	Out-of-Pocket Cost	Lack of Insurance Coverage	Low Public Trust in Mental Health System	PEI Not Available in All Areas	Stigma about PEI	Frequency of Treatment
Stakeholders
public (ref: psychiatrists)	2.91***	1.11	1.15	0.84	2.03***	0.31***	0.49***	1.19
caregivers (ref: psychiatrists)	2.57***	1.12	1.02	0.86	2.17***	0.38***	0.71*	1.23
patients (ref: psychiatrists)	2.53***	1.02	1.06	0.92	2.15***	0.41***	0.71*	1.23
Experimental Conditions
rTMS (ref: ECT)	1.02	0.59***	1.86***	1.54***	0.77*	1.13	0.43***	1.41***
DBS (ref: ECT)	1.47***	0.85	1.78***	1.42***	0.69***	0.87	0.52***	0.78*
ABI (ref: ECT)	2.10***	0.84	1.60***	1.43***	0.62***	0.73**	0.50***	0.79*
severe TRD (ref: moderate)	1.04	0.99	1.02	0.98	0.91	1.14	1.02	0.90
Perception of TRD
bad daily life with TRD	1.03	1.01	1.02	1.01	0.96*	0.94***	0.98	0.92***
Socio-Demographics
female	1.20*	1.11	1.04	1.12	0.78**	0.75***	0.70***	0.80**
age	1.07**	1.04	0.90***	1.02	0.86***	0.87***	0.92***	0.95
white	1.00	0.78**	1.17	1.16	0.75**	0.83	1.00	0.94
educational attainment	0.99	0.99	0.89***	0.99	1.06	1.00	0.94	0.92*
political ideology	1.03	0.99	1.04*	1.04	0.96	1.00	0.99	1.00
religiosity	0.97	1.00	0.99	1.02	1.05*	1.05*	1.04*	1.04
Nagelkerke R 2	.07	.02	.04	.02	.06	.06	.06	.04

^*p<.05

^**p<.01

^***p<.001

3.1. Views by Stakeholder Group

Non-clinicians were twice as likely to select limited evidence of treatment effectiveness and low public trust in mental health system among their top three perceived barriers than did psychiatrists. Compared to psychiatrists, non-clinicians were less likely to perceive stigma about treatment and treatment not available in all geographic areas as barriers.

3.2. Views by Modality and Depression Severity

Across all surveyed groups, compared to participants assigned to the ECT condition, those assigned to any of the other modalities were more likely to report out-of-pocket cost and lack of insurance coverage among their top three perceived barriers, and less likely to report low public trust in mental health system and stigma about treatment among their top three perceived barriers. For the implantable interventions (DBS, ABIs), limited evidence of treatment effectiveness was more likely to be among the top three perceived barriers than for ECT, whereas for rTMS frequency of treatment was more likely to be perceived among the top three barriers than for ECT. Depression severity had no effect on perceived barriers.

3.3. Influence of Stakeholder Group Membership on Views by Modality

Table 3 reports the standardized coefficients from multiple Ordinary Least Squares (OLS) regression models that are similar to those displayed in Table 2, but also contain a suite of interaction terms to investigate whether the influence of modality or depression severity on views varies across stakeholder groups. We draw attention to the most discernable patterns here.

Table 3:

Odds Ratios from Multiple Logistic Regression Models Explaining Top Perceived Practical Barriers to Use of PEIs across Key Stakeholder Groups with Interaction Terms (N=3603)

Predictors	Limited Evidence of PEI’s Effectiveness	Lack of Understanding of PEI	Out-of-Pocket Cost	Lack of Insurance Coverage	Low Public Trust in Mental Health System	PEI Not Available in All Areas	Stigma about PEI	Frequency of Treatment
Stakeholders
public (ref: psychiatrists)	4.00***	1.09	1.36*	0.88	2.45***	0.33***	0.57***	1.94***
caregivers (ref: psychiatrists)	3.56***	1.09	1.21	0.91	2.61***	0.40***	0.81	2.00***
patients (ref: psychiatrists)	3.48***	0.99	1.26	0.97	2.59***	0.43***	0.81	1.99***
Experimental Conditions
rTMS (ref: ECT)	1.29*	0.57***	2.08***	1.61***	0.66***	1.19	0.39***	1.41***
DBS (ref: ECT)	1.86***	0.83	1.99***	1.48***	0.66***	0.93	0.50***	0.66***
ABI (ref: ECT)	2.70***	0.82*	1.77***	1.49***	0.60***	0.76*	0.48***	0.70**
severe TRD (ref: moderate)	1.03	0.99	1.03	0.99	0.90	1.13	1.03	0.89
Perception of TRD
bad daily life with TRD	1.04*	1.01	1.02	1.01	0.96*	0.94***	0.98	.92***
Socio-Demographics
female	1.16	1.10	1.05	1.12	0.78**	0.76**	0.71***	0.82*
age	1.08**	1.03	0.90***	1.03	0.86***	0.87***	0.91***	0.95
white	0.98	0.78*	1.16	1.14	0.75**	0.83	1.02	0.94
educational attainment	0.98	0.80	0.89***	0.99	1.06	1.00	0.94	0.92*
political ideology	1.03	0.48	1.04	1.04	0.96	1.00	0.99	0.99
religiosity	0.96	0.78	1.00	1.02	1.05*	1.06*	1.04	1.04
Interaction Terms
rTMS * public	0.07***	5.13***	0.09***	0.17***	7.69***	2.92**	33.89***	0.36**
rTMS * caregiver	0.06***	7.21***	0.07***	0.13***	7.41***	2.13*	30.36***	0.40**
rTMS * patient	0.06***	5.29***	0.07***	0.11***	9.01***	1.24	32.16***	0.36**
DBS * public	0.02***	1.44	0.23***	0.29***	2.01	3.54***	14.90***	7.40***
DBS * caregiver	0.02***	1.97*	0.20***	0.19***	1.94	2.56**	11.79***	8.75***
DBS * patient	0.02***	1.89	0.18***	0.20***	2.16	1.59	15.72***	8.04***
ABI * public	0.01***	2.38*	0.21***	0.27***	1.93	5.91***	9.97***	6.48***
ABI * caregiver	0.01***	3.04***	0.13***	0.16***	1.61	4.99***	9.03***	6.29***
ABI * patient	0.01***	2.47**	0.24***	0.20***	1.86	4.39***	7.76***	4.38**
severe * public	1.21	0.99	0.76	0.96	1.37	0.76	0.81	1.19
severe * caregiver	1.63	1.11	0.79	0.77	1.09	0.67	0.76	1.35
severe * patient	1.35	0.82	1.12	1.15	1.17	0.74	0.71	1.38
Nagelkerke R 2	.13	.03	.07	.04	.07	.08	.10	.08

^*p<.05

^**p<.01

^***p<.001

First, assignment to the ECT condition moderates selection of a number of items as top barriers between psychiatrists and non-clinician groups. Specifically, non-clinician group participants in the ECT condition were more likely than psychiatrists to select limited evidence of treatment effectiveness, out-of-pocket cost, and lack of insurance coverage among their top three perceived barriers, and less likely to select treatment is not available in all geographic areas, lack of understanding of intervention, or stigma about treatment. Non-clinician group participants in the rTMS condition were more likely than psychiatrists to select limited evidence of treatment effectiveness and lack of understanding of intervention among their top three perceived barriers, and less likely to select lack of insurance coverage, frequency of treatment, or treatment is not available in all geographic areas,

Finally, in the DBS or ABI conditions, we did not find any strong differences among stakeholders for the main perceived barriers, which were limited evidence of treatment effectiveness and lack of understanding of intervention. Non-clinician participants were more likely than psychiatrists to select low public trust in mental health system and frequency of treatment as perceived barriers.

3.4. Views by Socio-Demographic Characteristics

Sociodemographic variables accounted for relatively little of the adjusted R² values across the models with a few exceptions. Compared to their male counterparts, females were more likely to perceive limited evidence of treatment effectiveness among their top three barriers, and less likely to perceive low public trust in mental health system, treatment is not available in all geographic areas, stigma about treatment, and frequency of treatment among their top three barriers. Older age is related to a higher likelihood of ranking limited evidence of treatment effectiveness among top barriers, and is less related to the likelihood of ranking out-of-pocket cost, low public trust in mental health system, treatment is not available in all geographic areas, and stigma about treatment among their top three perceived barriers. Finally, educational attainment, political ideology, and religiosity had only weak associations with some of the perceived barriers (see Table 2).

4. Discussion

Overall, these results provide considerable evidence that perceived barriers differ both between psychiatrists and non-clinician groups, and between neuromodulation interventions. Compared to psychiatrists, the non-clinician groups differ the most across their top three ranked perceived barriers. We also observed different patterns when comparing perceived barriers between the implantable and non-implantable interventions (Figure 1). Among the differences was the fact that stigma about treatment was considered a top barrier for ECT among psychiatrists but not for the non-clinical groups. Across both our clinician group and non-clinical groups, the top barrier for implantable neurostimulation technologies (DBS and ABIs) was limited evidence of treatment effectiveness. This was also a top barrier among non-clinical groups for both ECT and rTMS.

4.1. Barriers for Non-Implantable Interventions (ECT and rTMS)

For the two non-implantable and already approved interventions, one clear finding is that psychiatrists’ perceptions of barriers to treatment differ from those of the three non-clinician groups. For the non-clinician stakeholder groups, limited evidence of treatment effectiveness and lack of understanding of intervention were ranked among their top three perceived barriers to treatment for both ECT and rTMS. The fact that limited evidence of treatment effectiveness was selected as the top barrier by these stakeholder groups can be connected to low mental health literacy, including lack of awareness of available treatments, as information about these interventions might not be readily available to members of these groups^1,20,21. In contrast, for psychiatrists limited evidence of treatment effectiveness was not considered a main barrier for ECT and rTMS. This in part can be attributed to the fact that both these interventions are approved by the FDA for the treatment of depression, and there is evidence from clinical guidelines and systematic reviews showing the effectiveness of these treatments for treatment-resistant depression¹⁰.

Previous studies have examined perceptions of lack of knowledge of ECT as a barrier to the use of this treatment^8,21. We asked instead about lack of understanding, to capture both lack of knowledge of and misperceptions about this type of interventions. The three non-clinician groups all selected lack of understanding of intervention as a top barrier for both ECT and rTMS, while psychiatrists selected this item only for ECT. In fact, for psychiatrists in the ECT condition, lack of understanding of intervention and stigma about treatment were the two most commonly appearing items in participants’ top three barriers. Kring et al. (2018) explicitly linked stigmatizing attitudes toward ECT with lack of knowledge and experience of the treatment⁸. It is also possible that stigma might be an underlying factor behind the responses of our non-clinician participants in terms of their top two barriers (limited evidence of treatment effectiveness and lack of understanding of intervention), yet they might not be familiar enough with the term “stigma” to have chosen it as a key barrier, or they may not see stigma in the same ways as psychiatrists do.

It should also be noted that, although we asked specifically about stigma about treatment, depression itself is also stigmatized and this stigma might already evoke both uncritical fear and unwarranted skepticism toward its treatment. In addition, the relationship we observed between these items may reflect psychiatrists’ recognition that ECT has negative associations with past abuses in psychiatric medicine.^11–13 In addition, psychiatrists are more likely than other stakeholder groups to be aware of ECT’s potential negative effects on memory and cognition. A stigmatized perception of ECT can also have indirect effects on the way that non-clinicians view other neurostimulation interventions like rTMS; for instance, a recent study found that negative side effects of rTMS were perceived as “more acceptable” than those of ECT, in spite of the fact that the effects on neural tissue are still not well understood²².

Across all non-clinical stakeholder groups, out-of-pocket cost and lack of insurance coverage, were top barriers for both the ECT and rTMS conditions. For psychiatrists these were only ranked among their top barriers for rTMS. Financial barriers, such as cost and insurance coverage, are key concerns in the literature, not just for neurostimulation interventions but for other forms of mental health treatment.^1,20 For example, a previous article reviewing three national studies found that the most significant barrier to mental health treatment in general is insurance coverage²³. Wilkinson and colleagues (2018) found that, in the U.S., patients with private insurance coverage have higher rates of ECT treatment than patients with public insurance. Part of the difference might be due to privately insured patients being more likely to have the social support needed to undergo ECT on an outpatient basis, than some publicly insured patients. In discussing rTMS, Goldbloom and Gratzer (2020) point to access as a key barrier and the fact that rTMS remains largely unknown and underused¹⁴. Connected to our findings, psychiatrists perceived lack of insurance coverage and out-of-pocket costs as top barriers for rTMS, highlighting that treatment availability in a geographic region does not necessarily translate to ability to access that treatment.

In terms of differences by intervention, frequency of treatment was perceived as a key barrier by psychiatrists for rTMS. This is similar to previous findings highlighting the time it takes for the treatment itself and to transport to and from the treatment as being limiting^8,14,24. Standard rTMS protocols require sessions five days a week for at least six weeks; however, newer, shorter courses of treatment such as the SAINT protocol, which require a five-day consecutive treatment plan, may diminish the importance of this barrier²⁵.

Finally, it is important to emphasize that barriers to these types of treatment intersect in important ways and are not experienced equally by all patients. For example, financial and geographic limitations present compounding availability and accessibility barriers for accessing these interventions. When these interventions have limited availability, patients often have to travel long distances to receive treatment. In order to travel for treatments such as ECT or rTMS, which can sometimes be multiple days a week for multiple days in a row, patients and their caregivers might have to take time off of work, and pay travel, childcare and hotel costs. In addition, it is also important to consider that stigma might amplify access considerations, in particular, for vulnerable groups like racial and ethnic minorities, youth, men, and those in the military^26,27 who historically have been reticent to seeking mental healthcare.

4.2. Barriers for implantable interventions (DBS and ABI)

In contrast to the differences we saw between psychiatrists and non-clinician groups for the approved neurostimulation interventions, all four stakeholder groups perceived similar barriers for implantable interventions, with limited evidence of treatment effectiveness ranked as a top barrier. However, the reasons for this ranking may be different for psychiatrists and non-clinicians. In the non-clinician groups, this was the same as the top-ranked barrier for ECT and rTMS, and the reasons for its selection may be the same for all interventions. For psychiatrists, limited evidence of treatment effectiveness was a top barrier for DBS and ABIs, but not for ECT and rTMS. Selection of this item as a barrier for the implantable interventions was consistent with results in previous studies⁹. For clinicians, the experimental status of DBS and ABIs and lack of FDA approval or inclusion in treatment guidelines for MDD likely shaped their perceptions of limited evidence of treatment effectiveness for these interventions. Although in the vignettes presented to each group, we did not present DBS or ABIs as experiment therapies, it is likely that psychiatrists would know that they are not currently approved for use in the treatment of MDD. In addition, psychiatrists have varying levels of knowledge and experience with these experimental interventions. Confirming this, Cormier et al. (2019) found that physicians reported a lack of education on neurosurgical interventions during their residency.

For all groups, lack of understanding of intervention was among the top three barriers for the implantable modalities. For these non-approved interventions, it is reasonable to see lack of understanding as a top barrier, as investigators are still working to determine safety, efficacy, optimal patient selection and place in treatment²⁸. Even though stigma about treatment was not selected by non-clinician respondents among the top three barriers for implantable interventions, as discussed above, stigma might still underlie some of their choices of top barriers. Although the hope is that these perceptions will eventually fade, views of older procedures such as ECT and lobotomy may constitute a frame of reference for the general public in making sense of newer interventions in psychiatry, including DBS^24,29 .

When considering the current results on neurostimulation technologies compared to barriers for more common mental health treatments such as pharmaceuticals and psychotherapy, a few interesting points emerged. Our results agree with current literature on barriers to mental health treatments. Multiple survey studies by the World Health Organization (WHO) have identified lack of knowledge about mental health treatments as a barrier to accessing care^1,20. Other survey studies conducted by Mechanic and Tomczyk et al. have reached similar conclusions on lack of knowledge about mental health treatments as a significant barrier^23,30. This is more pronounced for neurostimulation treatments. Although only our clinician group identified stigma as a top barrier and only for ECT, other studies have found stigma to be a major barrier to mental health treatment^1,20,23,30 across other stakeholders. While our study found that cost and insurance coverage (access barriers) were noted as top barriers for ECT and rTMS, access problems were more commonly noted in studies about barriers to routine mental health treatments such as therapy and antidepressants. However, this discrepancy can be the result of the items we have listed for participants to choose among. A barrier that we did not identify in our study that did appear in the barriers literature is low perceived need for treatment from patients, or poor insight. The surveys conducted by the WHO, both domestically and internationally, found that one of the largest barriers to mental health treatment was that patients with depression or other psychiatric disorders did not believe they required treatment for their mental health, decreasing the amount of people actively searching out treatment^1,20. It is possible that this barrier is less salient in the case of neurostimulation, as they are considered second or third tier interventions, thus for patients to gain access to them they would need to be treatment seeking and have failed a first-line treatment first.

4.3. Strengths and Limitations

One of the main strengths of this survey is that it includes a large diverse national sample of stakeholders in the US, rigorous experimental design, and the fact that we assessed perceived barriers across multiple modalities of neurostimulation interventions. Limitations from this study include the fact that other key stakeholders were missing from our sample (including nurses). For our patient sample we relied upon self-reported diagnoses of depression (rather than getting the diagnoses directly from clinicians). Another important limitation includes distinction between perceived versus actual barriers to treatment.

We asked participants to comment on interventions for which they might not have had direct personal experience. There are other interventions that we could not cover for practical purposes as we needed to keep the overall number of experimental conditions to a manageable amount. Our findings highlight the need for future surveys to study barriers related to other neuromodulation interventions, such as vagus nerve stimulation and transcranial current stimulation, as well as to include the views of other stakeholder groups, including psychiatric mental health registered nurses and mental health technicians/counsellors.

Finally, it is challenging to infer reasons why respondents provided the answers they did without explicitly asking them. Future studies should examine the reasons why these differences exist to help guide educational/informational material to overcome perceived barriers and help clinicians and patients make the most informed decisions regarding their depression care. The identification of practical barriers could help inform policy decisions to allow better access to these treatments for those who may benefit from them.