Prevalence of pharmaceutical industry conspiracy theories among the polish population

Abstract

Conspiracy theories in the health domain can potentially erode trust in public health institutions and experts, resulting in non-compliance with public health guidelines and recommendations. This article aims to uncover and describe the widespread conspiracy theories associated with the pharmaceutical industry in Poland, while characterising the individuals who hold these beliefs. An online survey was conducted using a research-focused panel of participants. A quota sample of 1,057 was selected to reflect the basic demographic characteristics of the Polish population. Findings showed that pharmaceutical industry-linked conspiracy theories (PILCT) are widespread among respondents. The most popular theory regarding the concealment of drug side effects was held by 63.1% of respondents. Individuals with children, better financial situations, strong religious beliefs, living in a city or village with a population of less than 500,000 and a lower level of education tend to have higher PILCT beliefs. Higher PILCT beliefs correlate with reduced trust in doctors and the industry. Private healthcare services and vaccination behaviours (both irregular and regular vaccinations) are key predictors of lower PILCT beliefs. Considering the health risks and findings of this study, practitioners must be made aware of such widespread false beliefs to address this challenge properly.

Supplementary Information

The online version contains supplementary material available at 10.1038/s41598-025-95626-2.

Introduction

Conspiracy theories can discourage vaccination^1,2or healthcare services utilisation^3,4, public trust in institutions^5,6, and lead to non-compliance with health guidelines^6,7. The study presented will identify demographic groups that are more likely to believe in pharmaceutical industry-linked conspiracy theories (PILCT). This remarkable group of theories are significant not only to policymakers and health practitioners, but also to the pharmaceutical industry. Our research will provide valuable insights that can aid in designing interventions to combat conspiracy theories, as well as improve public awareness and education about the pharmaceutical industry’s role in health protection.

Conspiracy theories: conceptualisation and their correlates

Popper discussed the ‘conspiracy theory of society’ as early as the 1950s, framing it from the perspective that understanding social phenomena necessitates identifying individuals or groups with an interest in them (sometimes hidden), and who have developed plans and strategies to influence their occurrence⁸. However, this phenomenon remains blurry to this day, as harmless internet hoaxes, serious journalistic investigations, rational political criticism, and harmful distortions of facts, are all referred to using this term⁹. Researchers use very different, arbitrary definitions in their texts depending on their needs¹⁰. This study examined theories that view the pharmaceutical industry as a group with hidden objectives. This group is portrayed as evil, improbably powerful, competent, and malevolent, similar to the subjects of other conspiracy theories¹¹. Following Blaskiewicz¹¹, we have accepted that there may be real, tangible facts underlying these conspiracy theories.

Belief in conspiracy theories is often associated with of perceiving of the world as dangerous, difficult to control, and unpredictable¹². Faith in conspiracies is linked to feelings of isolation, helplessness, and animosity¹³. Conspiracy mentality is deeply rooted in a complex interplay of psychological tendencies to distrust authority, perceive significant events as the result of conspiracies, and be driven by ideological motivations¹⁴.

Moreover, various socio-demographic characteristics have been linked to conspiracy beliefs. One such example is lower levels of education^2,15–19. Such findings may lead to the suspicion that education can foster critical thinking skills, which may reduce susceptibility to such beliefs²⁰. Additionally, a lack of education may influence the epistemic need for knowledge¹⁰. Therefore, reducing conspiracy beliefs through enhanced education is a possibility²¹. Having children is another socio-demographic feature that has proven to be influential in believing in conspiracy theories²². Parental concerns, particularly those related to the health and safety of their children, can significantly influence beliefs in conspiracy theories, especially those pertaining to vaccinations^23,24. Psychological traits associated with parenting, such as heightened vigilance and protective instincts, may predispose individuals to conspiracy²⁵. Similarly, numerous studies have shown that lower income is also linked to a higher likelihood of adopting conspiracy beliefs^2,15,17,19. Both parental concerns and lower income can create greater existential needs for security, which, in turn may, amplify susceptibility to conspiracy theories¹⁰.

Moreover, individuals experiencing life dissatisfaction are more inclined to adopt conspiratorial narratives²⁶, partly because lower life satisfaction is associated with higher anxiety²⁷, which has been shown to directly fuel belief in conspiracy theories^28,29.

Individuals who subscribe to conspiracy theories exhibit poorer physical health¹⁷. Those with health problems and related distress might be more inclined to turn to conspiracy theories to understand their suffering or to find reasons behind their health issues.

Research has also shown that residence in less densely populated areas matters¹⁵. Although not explicitly stated by Douglas and Sutton¹⁰, it is plausible that living in marginalised communities may be associated with feelings of alienation. The social context in which individuals find themselves can influence their susceptibility to conspiracy theories. Research findings are inconsistent regarding demographic features that affect beliefs, such as age (with some studies indicating older individuals and others younger individuals)^2,15,16,19and gender (with some studies indicating males and some females)¹⁹.

Religiosity often provides a comprehensive worldview or ‘sacred canopy’³⁰where religious beliefs explain the nature of existence, morality, and the unseen forces that guide the world. Therefore, it is not surprising that research has often found a connection between religiosity and conspiracy theories^18,19,31. Conspiracy theories can also serve as an alternative worldview that offers simplified explanations for complex events, particularly those that seem threatening or inexplicable within conventional narratives. Both religiosity and conspiracy theories help create coherence in the believer’s worldview, offering explanations that might be difficult to find in purely secular or mainstream contexts. At the same time, both religiosity and conspiracy theories offer mechanisms for reducing existential anxiety and uncertainty in the face of uncontrollable or frightening events. Sociologists like Luckmann have noted that religion provides a ‘sacred cosmos’ that gives meaning to human existence and offers explanations for suffering, evil, and chaos³². Conspiracy theories can serve a similar function by providing clear, although often simplistic, explanations for complex events (e.g., economic crises, political turmoil, public health crises) that alleviate feelings of powerlessness and confusion.

Pharmaceutical Industry-Linked conspiracy theories and their impact on modern public health threats

The recent COVID-19 pandemic provided an ideal environment for the spread of misleading information. The pandemic has also underscored the dangers of PILCT, which threaten public health, particularly their role in discouraging vaccinations^1,2,33. The anti-vaccine movement was active long before the outbreak of the pandemic. It relies on misleading information and often rejects scientific evidence. An example is the ongoing argument regarding the association between autism and the MMR vaccination which was revealed to be fabricated³⁴.

During the pandemic, various conspiracy theories related to the SARS-CoV-2 virus, believed by some Poles, were investigated. These theories included the idea of COVID-19 as a weapon^35,36, COVID-19 as a hoax^35,37, COVID-19 being released to reduce the population^38,39, government conspiracies^35,36, the presence of microchips in vaccines³⁶, and that the 5G network induced the pandemic⁴⁰. Some studies also discussed the role of the PILCT^37,39,40. One of these theories suggested that pharmaceutical companies helped to release the coronavirus to profit immensely from selling vaccines during the pandemic. This was examined in a few studies^37,39,40. There was also a study checking if Poles believed that the anti-vaccine movement was correct and if natural treatments were more effective than medicines⁴¹. The results of this study⁴¹ indicated that a portion of the Polish population has low trust in conventional medicine (22.2% of respondents agreed that the anti-vaccine movement is correct, and 20.2% believed that natural remedies are more effective than medications).

Another very dangerous PILCT is the Big Pharma Conspiracy⁴², alleging that large pharmaceutical corporations conceal information, manipulate data, and manufacture diseases for profit. It is worth emphasising that Big Pharmahas agents, including medical doctors, politicians, and patient organisations, also profit from medicine sales and cooperate with the industry¹¹.

The next popular PILCT suggests that the pharmaceutical industry is concealing a cure for cancer. Others claim that diseases are created and viruses are released from laboratories to increase the sales of medications^1,2,43. Blaskiewicz¹¹ characterised theories of this nature as connected to the often fallacious ‘cui bono’ (Latin for ‘who benefits’) principle, which implies that those who benefit from a misfortune are assumed to be responsible for it. This reasoning also suggests that the industry is withholding inexpensive natural remedies to promote the sales of expensive ones^1,2.

Moreover, we live in a world of the internet and social media, where conspiracy theories find fertile ground to spread rapidly. Nevertheless, the internet offers individuals access to knowledge and science like never before. The pharmaceutical industry provides evidence of its crucial role in maintaining public health by producing medicines that effectively address healthcare needs and alleviate illnesses. A COVID-19 vaccine was rapidly developed, and two scientists working on mRNA COVID-19 vaccines won the Nobel Prize in Medicine⁴⁴. Life expectancy has increased by 30 years in high-income countries over the past century, and cancer mortality has decreased by 20% in the last 20 years, partly because of medications⁴⁵.

However, the industry has encountered legitimate criticism concerning several aspects of its operations owing to its pursuit of profits. These include its influence on testing and clinical trials for new medications, control over scientific processes^46,47, pressure on regulatory bodies^48–51, inadequate investment in R&D⁴⁸, expansion of disease diagnostic boundaries, and disease-mongering^47,49,52. Moreover, it has been criticised for aggressive drug marketing^48,53–56, corrupt agents^48,57, influence on medical education^48,49,58, inflation of drug prices^{45,48,59–61}, extension of patents and discouragement of generic drug manufacturers^48,60,62, and the promotion of the off-label use of medications^56,63,64.

There have been cases of pharmaceutical companies concealing drug side effects, such as Merck Inc. with Vioxx and Servier with Mediator. These incidents garnered significant media attention and eroded trust in the industry^65,66. The media has also widely disseminated knowledge about the opioid epidemic in the United States, in which pharmaceutical marketing plays a significant role⁵⁶. Such corporate misconduct is both economically and socially detrimental and comes at a high cost, creating an unfriendly environment for pharmaceutical companies and fuelling conspiracy theories. Deviant corporate behaviour can be understood in light of Merton’s anomie theory, although it originally pertained to individual behaviour⁶⁷. An essential idea presented by Merton⁶⁸is the concept of disparities between cultural goals and the resources provided by institutions to attain these objectives. This leads to diminished adherence to established norms, referred to as anomie, and can result in deviant behaviour. A corporation’s cultural goal is to maximise profits, and there is ‘no defined and definite stopping point, the target is a moving one’⁶⁷.

Research gap and research questions

In Poland, ethical concerns about pharmaceutical industry marketing first arose the early 21st century⁶⁹. Over time, conspiracy theories about Big Pharma began to take root in people’s minds. Additionally, an anti-vaccination movement started to develop in Poland, and the number of unvaccinated people began to rise⁷⁰. Polish society has another trait that contributes to the spread of conspiracy theories: problems with social trust. Sztompka⁷¹referred to Polish culture as a ‘culture of distrust’ and Centre for Public Opinion Research (CBOS) studies have consistently revealed persistently low levels of social trust in Poland over an extended period⁷². During the COVID-19 pandemic, Poland was the only country where healthcare professionals were not the most trusted individuals; family and friends held the highest levels of trust among the Polish population⁷³. This article aims to identify the prevalent conspiracy theories related to the pharmaceutical industry, and characterise the individuals who believe them. It will address a research gap concerning PILCT in Poland, contributing to the global discussion on public health. Previous research has also linked belief in conspiracy theories to country of origin, finding that people from Eastern European countries exhibit higher levels of conspiracy beliefs^74,75. Therefore, the prevalence of conspiracy theories related to pharmaceutical companies, and the socio-demographic features characterising people who believe in them may differ in Poland compared to other countries. The study is of the exploratory nature^76,77 and was not intended to test predefined theories or verify specific hypotheses. Instead, its primary aim was to investigate emerging phenomena and underexplored research areas, collect preliminary data, and gain a deeper understanding of a problem that has not yet been comprehensively examined. Accordingly, the focus was placed solely on formulating research questions: (1) What percentage of the Polish population believes conspiracy theories related to the pharmaceutical industry? (2) What are the most popular theories? (3) Are there any sociodemographic features that make people more likely to believe them?

Methods

Study design and sample size

This study was a cross-sectional, online quantitative survey conducted in 2023. It used a quota sample of 1057 Polish respondents. The sample was meticulously crafted to mirror Poland’s demographic composition, encompassing essential variables such as gender, age, educational level, region, and the population size of respondents’ places of residence.

In Poland, around 20 million adults have access to the internet. Assuming an alpha of 0.05, a desired power of 0.80, a (small) effect size of d = 0.2, and an allocation ratio of 0.25 for t-tests, G*Power 3.1⁷⁸ suggested a sample of 968 people. But, since the actual allocation ratios for different analyses were unknown, we erred on the side of caution and aimed to gather data from 1000 respondents. A quota sample of 1,057 people was obtained for the study. Cross quotas were used for gender, age, and population size of place of residence, resulting in 50 layers. At the researchers’ request, the categories of region (voivodeships) and education (2 categories) were marginally added. Quotas were based on Polish Central Statistical Office (GUS) data and prepared by Adriadna Panel. Funding to compensate the panel was provided by the Kozminski University ‘small grant’. The mean age of the respondents was 46 years, with a standard deviation of 16 years. Of the sample, 52.8% were women, and 47.0% were men (those identifying otherwise were excluded). Moreover, 24.8% had education higher than secondary, while 75.2% had secondary or lower education. Appendix A contains the distributions of the respondents’ socio-demographic characteristics used in quota sampling.

Recruitment and data collection

We conducted an online survey distributed via an Ariadna internet panel, which is one of the largest internet panels in Poland. Respondents independently sign up and register in the panel, providing their demographic characteristics, to complete social surveys for points. This approach enabled us to create to create a sample that proportionally reflected the population of Poland. Participants received 15 points from the panel for completing a survey, while those who were invited but did not meet the sample criteria received 1 point. Points from multiple surveys could be exchanged for prizes selected from the panel’s catalogue. Typically, respondents took approximately 12 min to complete the survey.

Survey design

The questionnaire was specifically designed for this study, which had exploratory objectives focused on understanding public perceptions of general physicians, the pharmaceutical industry, and patient organisations. The survey included 16 sociodemographic questions, that capture essential demographic information such as age, gender, education level, and health status. This allowed for a comprehensive analysis of how these factors may influence respondents’ views. In addition to the sociodemographic section, the questionnaire featured six key inquiries, each comprising 4 to 22 rated on a 10-point Likert scale ranging from 1 (strongly disagree) to 10 (strongly agree).

For this article, six statements related to conspiracy theories were selected and presented in varying orders among 17 other statements from the latest key inquiry. This approach was intended to minimise response bias and ensure that participants engaged thoughtfully with each statement. The initial enquiry, which focused on trust in different institutions, was also considered valuable for this article. Both the questionnaire and the database are freely accessible via the following link: https://figshare.com/articles/dataset/Transparency_Sunshine_Act_Poland/24598488.

Ethical committee approval

The Research Ethics Committee of Kozminski University approved the project on 4/5/2023 based on RESOLUTION No. 8–2021/2022 of the Kozminski University Senate dated 16 December 2021. All participants gave written informed consent. The study was conducted in accordance with the Declaration of Helsinki (2008).

Data analysis

Data were analysed using SPSS 29. Below, we present distributions and descriptive statistics (means, standard deviations, medians, and quartiles) relating to respondents’ answers regarding specific statements concerning the PILCT and social trust. Distributions of responses to all statements analysed were not normally distributed (Shapiro-Wilk tests, [1057], p< .01 in all cases) and responses were ordinally scaled. However, given our large sample size⁷⁹, the large number of response options on our Likert-type response scales, and the fact that it was reasonable to assume that the ordinal scales had continuous scales, underlying them it was thought reasonable to use parametric tests. Tabachnick and Fidell⁸⁰ say that in practice a criterion of ‘…seven or more…’ is often used to decide whether ordinal scales should be treated as continuous.

An index was constructed from the statements relating to PILCT (Cronbach’s alpha = 0.862), representing the average response value (in the range of 1 to 10) to the six included statements. These statements are based on a narrative literature review and the independent opinions of experts (reached online and surveyed) regarding Poland’s most popular pharmaceutical industry-related theories. However, there may be other popular theories that we did not consider mainly due to the limited questionnaire size. A linear regression analysis was conducted to investigate whether Poles’ beliefs in Big Pharma conspiracy theories are related to specific sociodemographic characteristics. The other variables taken into account were self-assessed financial situation (5-item scale from very good to very poor), self-assessed health status (5-item scale from very good to very poor), and life satisfaction (5-item scale from definitely yes to hard to say).

Religious practices were measured by participation in religious activities such as masses, services, or religious meetings (5-item scale from several times a week to not at all). Religious belief was measured independently of practices (using a 4-item scale from strong believer to non-believer), as we were aware that these two variables do not always fully coincide.

Also, statements relating to trust were correlated (Pearson’s r) with scores on the above mentioned conspiracy theory index. Finally, multiple linear regression was employed to predict PILCT index values based on healthcare system usage. The predictors included the type of healthcare services used (1: I used only benefits under universal state health insurance, 2: I used only self-paid or private insurance services, 3: I used benefits under universal state health insurance and self-paid/private benefits, with 3 as the reference group), and COVID-19 vaccination status (1: Yes – I took one dose or more but do not get vaccinated consistently, 2: Yes – I get vaccinated regularly, 3: No vaccinations, with 3 as the reference group).

Results

Belief in conspiracy theories and its predictors

The present data in Table 1 indicates that Poles are divided in their beliefs about conspiracy theories relating to the pharmaceutical industry. Based on the six statements from Table 1, the conspiracy theories index (PILCT index) was constructed, representing a person’s average response to the six statements in Table 1Cronbach’s alpha represents the average split-half correlation coefficient for items included in its calculation. Note that, besides to verifying an important metric characteristic of the index, since, the substantial size of this coefficient (0.862) supports previous findings in the literature showing that individuals who endorse one conspiracy theory also tend to endorse others¹⁰.

Table 1.

Descriptive statistics for all statements used in the PILCT index. N = 1057.

No		1–2 (definitely disagree)	3–5	6–8	9–10 (definitely agree)	M (SD)	Mdn (Q1 -Q3)
1	Pharmaceutical companies hide the side effects of their drugs.	7.9%	28.9%	41.8%	21.3%	6.35 (2.43)	6.0 (5–8)
2	Pharmaceutical companies invent new diseases to sell their drugs.	13.9%	31.1%	37.2%	17.8%	5.80 (2.64)	6.0 (4–8)
3	Pharmaceutical companies are hiding a cure for cancer.	20.1%	33.7%	28.9%	17.3%	5.42 (2.83)	5.0 (3–8)
4	Natural treatments (e.g., herbs, and a good diet) are more effective than medications.	11.8%	43.8%	51.9%	9.4%	5.36 (2.27)	5.0 (4–7)
5	Pharmaceutical companies are responsible for releasing the coronavirus	28.2%	33.8%	26.8%	11.3%	4.74 (2.76)	5.0 (2–6)
6	The anti-vaccine movement is right about many things.	30.7%	31.4%	24.7%	13.2%	4.70 (2.90)	5.0 (2–7)

The average value of the PILCT index (which can range from 1 to 10) for the whole sample of respondents was 5.40. This is slightly below the midpoint of the scale (5.50), suggesting that Polish people are somewhat more inclined not to believe in researched conspiracy theories than to believe in them.

Multiple regression analyses tested whether socio-demographic variables significantly predicted PILCT index scores. The results indicated that, overall, the socio-demographic variables were significantly predictive of PILCT index scores, F(10,837) = 7.651, p < .001. Nonetheless, the model’s explanatory capacity was restricted since it explained only 8.4% of the variance in PILCT index scores, R = .289, R² = 0.084. Regression coefficients for the analysis are presented in Table 2, which shows that independent significant predictors were the number of children in a household, educational level, population of residential area, financial situation, and religious beliefs. Thus, respondents were more likely to believe in conspiracy theories regarding the pharmaceutical industry if they had a lower level of education, had at least one child in their household, lived in a city or village with a population less than 500,000, and perceived their financial situation more favourably. Belief in conspiracy theories was significantly higher among religious believers and people who were undecided than non-believers. Variables such as gender, age, life satisfaction, and perception of health status were nonsignificant independent predictors in the model.

Table 2.

Prediction of PILCT index scores from socio-demographic variables (multiple regression analysis: N = 847)*.

Independent variable	B	SE	Beta	t	p	sr**
Age (continious)	0.002	0.005	0.013	0.358	0.721	0.012
Gender (1 -female, 0-male)	− 0.029	0.137	− 0.007	− 0.214	0.831	− 0.007
Children in household (1-at least one, 0 - any)	0.705	0.151	0.161	4.665	< 0.001	0.154
Level of education (1 - higher then secondary 0 - secondary and lower )	− 0.533	0.157	− 0.114	−3.383	< 0.001	− 0.112
Size of residential area (1 - city over 501 K 0- village and city up to 500 K )	− 0.609	0.207	− 0.099	−2.942	0.003	− 0.097
Financial situation (1-good, very good, 0- moderate, poor, very poor)	0.345	0.154	0.081	2.234	0.026	0.074
Life satisfaction (1 –not satisfied, 0- satisfied)	− 0.063	0.189	− 0.012	− 0.332	0.740	− 0.011
Self-assessment of health status (1 - very good, good; 0 - moderate, poor, very poor)	− 0.105	0.152	− 0.026	− 0.689	0.491	− 0.023
Religious practices (1 - not at all, 0 -at least sometimes)	− 0.295	0.179	− 0.067	−1.642	0.101	− 0.054
Religious beliefs ( 1 - undecided, non-beliver, 0 - strong believer, believer)	− 0.360	0.181	− 0.081	−1.984	0.048	− 0.066
Constant	5.343	0.266		20.120	< 0.001

* The analysis meets the assumptions of multiple regression, i.e., there is no strong linear relationship among predictors, the error distribution is close to normal, and the assumption of homoscedasticity is met.

** Semi-partial correlation (sr) is a statistic used in multiple regression analyses to understand the unique contribution of each predictor variable to the dependent variable.

It should be noted that while a chi-square test of association not reported in the interests of brevity showed a significant association between membership in a religious belief and religious practitioner groupings, variance inflation factors in the multiple regression analysis did not indicate problems with multicollinearity for the religious variables: religious practices (VIF = 1.53) and religious beliefs (VIF = 1.52).

Belief in conspiracy theories and trust

Along with measures of central tendency and spread, Table 3 presents percentages of respondents endorsing different scale points for items asking about trust in various entities.

Table 3.

Descriptive statistics for statements about trust (N = 1057).

No	In general, do you trust:	1–2 (definitely disagree) %	3–5%	6–8%	9–10 (definitely agree) %	M (SD)	Mdn (Q1-Q3)
1	Medical doctors	5.9	26.5	56.8	10.9	6.28 (2.07)	7.0 (5–8)
2	Non-governmental organisations	8.3	32.3	48.7	10.7	5.94 (2.24)	6.0 (5–8)
3	Pharmaceutical industry	16.4	39.1	39.8	4.7	5.03 (2.27)	5.0 (3–7)
4.	Government	47.2	28.9	18.0	5.9	3.53 (2.67)	3.0 (1–5)

Pearson’s r correlation analyses between PILCT index scores and the above trust indicators showed that the higher the belief in conspiracy theories, the lower the trust in both medical doctors, r (1055)=−0.264, p < .001, and the pharmaceutical industry, r(1055)=−0.217, p < .001. However, though significant and with values high enough to indicate a small effect size (r = .20), these coefficients were surprisingly small.

While statistically significant (p < .05), both of the other coefficients were not high enough to indicate a small effect size. As belief in conspiracy theories increased, trust in non-governmental organisations decreased, r(1055)=−0.161, p < .001. But interestingly, in the case of trust in the government, the correlation was in the opposite direction: the higher the belief in conspiracy theories, the higher the trust in the government, r(1055) = 0.08, p = .006. However, given that the coefficient is very low, this indicates a weak relationship (see Table 4).

Table 4.

Pearson’s R correlations between PILCT index scores and trust indicators.

No.	Trust in	r(1055)	p
1	Medical doctors	− 0.264	< 0.001
2	Non-governmental organisations	− 0.161	< 0.001
3	Pharmaceutical industry	− 0.217	< 0.001
4.	Government	0.08	0.006

Belief in conspiracy theories and use of healthcare services

Multiple linear regression analysis was conducted to predict PILCT index values based on the type of healthcare services used and vaccination status.

Although the model was statistically significant, F(6,1050) = 31.23, p < .001, the predictors accounted for a modest proportion of the variance (approximately 15.1%) in the PILCT index (R² = 0.151, adjusted R² = 0.147). The standard error of the estimate was 1.88.

The results of the regression analysis are presented in Table 5. The analysis revealed that individuals who used private healthcare services had significantly lower PILCT scores than those who used public services. Similarly, irregular and regular vaccinations were associated with lower PILCT scores. Neither public healthcare use nor mixed healthcare services showed significant associations with the PILCT index.

Table 5.

Prediction of PILCT index scores from healthcare usage (multiple regression analysis: N = 1057)*.

Independent variable**	B	SE	Beta	t	p	sr**
Public healthcare services (1-used, 0 – not used)	0.122	0.140	0.029	0.868	0.386	0.027
Private healthcare services (1 – used, 0 – not used)	− 0.476	0.218	− 0.067	−2.188	0.029	− 0.067
Mixed healthcare services (1 – used, 0 – not used)	− 0.164	0.165	− 0.032	−0.991	0.322	− 0.031
Irregular vaccinations (1 – yes, 0 – no)	−1.329	0.305	− 0.323	−4.352	0.000	− 0.133
Regular vaccinations (1 – yes, 0 – no)	−1.911	0.317	− 0.397	−6.032	0.000	− 0.183
No vaccinations (1 – yes, 0 – no)	0.026	0.310	0.006	0.084	0.933	0.003
Constant	6.439	0.296		21.748	< 0.001

* The analysis meets the assumptions of multiple regression, i.e., there is no strong linear relationship among predictors, the error distribution is close to normal, and the assumption of homoscedasticity is met.

** Semi-partial correlation (sr) is a statistic used in multiple regression analyses to understand the unique contribution of each predictor variable to the dependent variable.

Discussion

As this survey was conducted within one nation, comparing its results rigorously with those of other countries proves challenging. For context, a 2005 U.S. survey conducted by Gansler et al. revealed that 27.3% of participants believed in the misconception that a cure for cancer exists, but the medical industry withholds it for profit from treating cancer patients⁴³. In a 2018 study on a representative sample of the Italian population, 50% of respondents believed that pharmaceutical companies hinder the development of effective treatments for serious diseases⁸¹ In our study, 46.2% of participants agreed with a similar statement that pharmaceutical companies are concealing a cure for cancer.

The concept of the pharmaceutical industry creating diseases for profit has been widely discussed for many years^47,49,52.The pandemic has further intensified these suspicions⁸². In our study, more than half of the respondents shared this belief.

Erokhin et al.⁸³ gathered over one million tweets related to conspiracy theories during the COVID-19 pandemic, identifying a group associated with Big Pharmaand vaccine-related conspiracies. In a U.S. study by Romer and Jamieson², 14.8% of respondents believed that the pharmaceutical industry had created the virus.

One study analyzing various reports related to COVID-19 vaccines and misinformation from 52 countries indicated that the pharmaceutical industry appeared in rumors and conspiracy theories in the analyzed documents. Some of these, while not very prevalent in Poland and thus not included in our index, are worth mentioning. These include:1) the claim that pharmaceutical companies withheld positive news about vaccine development until after the 2020 election in the USA, suggesting a connection with political interests; 2) the claim that the COVID-19 vaccine was developed before the pandemic to boost vaccine sales; 3) the claim that the COVID-19 vaccine is intended to genetically modify humans. In our research, significantly more participants (38.1%) believed that pharmaceutical companies were responsible for releasing the coronavirus, and 37.9% stated that the anti-vaccine movement was correct about many things.

Our findings indicate that Poles were, on average, not inclined to believe in the conspiracy theories examined. The PILCT index midpoint, representing a ‘neutral’ stance, is 5.5, and in our research, the mean was slightly below this (5.4).While the exact mechanisms remain elusive, belief in conspiracy theories often align with various forms of marginalisation - economic, social, or political¹⁰. In Poland, most original pharmaceuticals, including COVID-19 vaccines, are developed by international companies; the Polish market primarily consists of generic medication⁸⁴. Therefore, it is unsurprising for scepticism to arise in a nation where new, highly-priced drugs originate from wealthy international corporations with a greedy reputation⁸⁵. Drug prices in Poland are frequently discussed in the media, often highlighting concerns about their high levels⁸⁶. Given that Poland’s healthcare system is predominantly publicly funded⁸⁷, there is a perception that pharmaceutical companies prioritise profit over public health.

Additionally, historical societal divisions between the ingroup and outgroup have long been influential in Poland¹², contributing to the development of conspiracy theories; we (Poles) versus them (others). Consequently, as most pharmaceutical companies are based abroad, they may be perceived as an outgroup acting against the interests of the Polish nation, which fosters the development of conspiracy theories.

The recent COVID-19 pandemic has served as an additional catalyst for conspiracy theories, alongside historical factors. The rapid spread of misinformation through social media during the pandemic created fertile ground for developing of such theories⁸⁸. In Poland, as in other nations, the uncertainty surrounding the pandemic has led to a notable rise in conspiracy beliefs^2,88,89. Undoubtedly, this was also influenced by the issues with trust among Poles mentioned in the introduction^71,72.

Our results also point to the relationship between trust in doctors and pharmaceutical companies and belief in PILCT. Unsurprisingly, lower trust in medical doctors is associated with higher belief in conspiracy theories, and the same applies to the pharmaceutical industry. These results underscore the importance of ethical conduct by doctors and the pharmaceutical industry, especially in their joint relations, which have been criticised for years, including in Poland^69,90,91. Managers in the pharmaceutical industry should understand the consequences and roots of corporate deviant behaviour described in the Introduction.

Conspiracy theories also appeal to individuals for political reasons². They are often associated with anxiety^28,29, which political narratives can influence. Our study found a weak but significant association between higher trust in the government and stronger belief in conspiracy theories. This finding was surprising, as it diverges from the prevailing literature^92–94 which typically suggests that trust in institutions, including the government, acts as a buffer against conspiracy thinking.

However, this counterintuitive result may be contextualised by the unique political environment in Poland during the study period. At that time, the government was led by the right-wing, and research has consistently shown that conservative individuals tend to believe in conspiracy theories more frequently than their liberal counterparts^2,31,95. It is essential to emphasize that the observed relationship was weak. This indicates that while the political context may partially explain the association, other factors could play significant roles in shaping these beliefs. This requires further investigation.

The results indicate that regular and irregular vaccinations, and the use of private healthcare are significant predictors of lower levels of belief in conspiracy theories. Specifically, the results concerning vaccination are consistent with previous research, which indicates that vaccine acceptance is linked to a reduced belief in conspiracy theories^4,96. However, the connection between private healthcare and conspiracy beliefs is more nuanced. It is often shaped by factors such as public trust, institutional credibility, and the socio-political context surrounding healthcare systems. Notably, in Poland, trust in the private healthcare system is considerably higher than in the public one⁹⁷.

Moreover, individuals who feel safe and in control do not believe in conspiracy theories¹⁰. Thus individuals who can access private healthcare feel safer using healthcare that offers faster access to medical services, a wide selection of doctors and facilities, and additional benefits.

To our knowledge, this is the first article focusing solely on pharmaceutical industry-linked conspiracy theories in an Eastern European country. It provides health experts, policymakers, and the pharmaceutical industry with important knowledge about the predictors of belief in PILCT. By understanding these predictors, they can more effectively tackle them and enhance public trust. The main insight from our study underscores the critical need to address and dispel false beliefs about the pharmaceutical industry to promote effective healthcare practices and informed decision-making.

Our research highlights the necessity for targeted interventions tailored to specific socio-demographic groups, including individuals from rural areas, those with lower levels of education, religious believers and practitioners, and families with children. These recommendations align with existing literature, emphasising the importance of addressing these groups’ problems. However, our study also uncovered an intriguing finding: individuals in better financial situations were more likely to believe in PILCT. This result contradicts previous studies^2,15,17,19, which typically suggest that lower socioeconomic status is associated with a higher belief in conspiracy theories. This was unexpected and suggests the possibility of a suppressor variable influencing this relationship. Identifying this variable could provide deeper insight into the complexity of how financial status is connected with conspiracy beliefs.

Additionally, the connection between having children in the household and the propensity to believe in conspiracy theories remains unclear and warrants further investigation. It would be logical to assume that having children in a household would make people think more rationally. Still, it is also possible that it increases anxiety about the future and their children’s health, leading to greater suspicion. Moreover, one of the biggest debates surrounding vaccinations specifically concerns vaccinating children, which could also play a role.

A significant limitation of this study is the lack of assessment of the metric properties of PILCT index, primarily due to constraints in time and budget. Consequently, the findings should be interpreted as preliminary. Future research endeavours will address this limitation by thoroughly evaluating and validating the metric properties of the index. Also qualitative studies, should be conducted to gain deeper insights. Engaging directly with individuals who hold PILCT can provide a clearer understanding of their perspectives and motivations. This, in turn, will aid in developing targeted and effective programs designed to combat the spread of such beliefs and promote accurate information about the pharmaceutical industry.

Another limitation of our study is its reliance on an online quota sample. Such a sample cannot be considered fully representative, as not all Poles have internet access⁹⁸, especially older, people from small places of residence. Individuals who subscribed to the panel might exhibit specific biases, participating in surveys primarily for the points. Our survey also asked about social sex, not biological, as in GUS. Furthermore, if the population demographics are evolving more rapidly than the updates to the data from GUS, the established quotas may become outdated and fail to reflect the current population structure accurately. Moreover, we did not investigate the individual reasons for participants’ agreement with each statement related to the theory. Consequently, the specific underlying mechanisms of these beliefs remain unclear. This limitation hinders the individualisation of targeted interventions to address this issue.

The study was not preregistered, which might slightly affect the credibility of our findings.

Conclusion

Conspiracy theories associated with the pharmaceutical industry are notably prevalent in Poland. The study’s timing - the recent COVID-19 pandemic - and misinformation about vaccines may have contributed to the theory’s broad endorsement among participants. The potential of this study lies in its ability to shed light not only on the prevalence of PILCT in Poland but also on the social demographic characteristics of those who are more prone to believe in them. This provides greater opportunities to combat these beliefs for the benefit of public health. Several steps are recommended for future research. First, the results should be verified through alternative sampling methods to address the representational limitations of Internet surveys. Second, further research is required to understand why a significant portion of the Polish population subscribes to conspiracy theories. A promising approach involves conducting qualitative research through semi-structured interviews or analysing existing data, such as documentary analysis, which has been proven effective in prior conspiracy theory research^99,100. These exploratory methods could reveal the underlying reasons for these beliefs. Subsequently, a multi-country survey could be undertaken. Identifying interventions that can effectively address conspiracies within the Polish context is crucial. Despite the potential of several strategies, targeted empirical studies are essential for ascertaining their efficacy.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Author contributions

Author contributions statement: Conceptualization-M.M.; methodology-M.M.&R.B.; formal analysis-M.M.&R.B.; writing-M.M&R.B.&A.O.; writing—review and editing-M.M&R.B.&A.O.; project administration-M.M.; funding acquisition-M.M. All authors have read and agreed to the published version of the manuscript.

Funding

This research received funding in the form of ‘small grant’ from Kozmininski University. The article processing charge (APC) was funded by the Warsaw University of Life Sciences.

Data availability

Both the questionnaire the database are freely accessible via the following link: https://figshare.com/articles/dataset/Transparency_Sunshine_Act_Poland/24598488.

Declarations

Competing interests

The authors declare no competing interests.

Ethics approval

Research Ethics Committee of Kozminski University approved the project on 4 May 2023 based on the RESOLUTION No. 8–2021/2022 of the Senate of Kozminski University of 16 December 2021.

Consent to participate

All respondents gave written consent.