The findings of this mixed methods project consistently showed limited impact of the Covid-19 outbreak on the illegal substance market and substance use among the studied sample. Despite the unprecedented barriers to the transport and supply of illegal substances that were created to contain the pandemic, both quantitative and qualitative data showed minor differences in the market. Over the two waves of quantitative data collection covering periods with various levels of lockdown measures, the use, price and purity of three main illegal substances did not significantly vary. Substance prices and purity basically mirrored those measured in studies before the pandemic [2–4]. Nonetheless, there was some variability and non-significant trends indicating small effects that our limited study design may not have captured. Data from the qualitative study similarly indicated relatively stable conditions in the drugs black market. There seemed to be no shortages and few changes in heroin purchases. It also appeared that the cocaine market remained relatively stable, although the price of “small baggies” rose slightly and there were periods with more proactive dealers in the streets. However, the cannabis market was a different case, particularly for resin (hashish). There were several indications of restricted supplies, together with increases in price and scams. One participant mentioned very bad resin making him vomit, which might indicate the production of low quality resin adulterated with synthetic cannabinoids. This had not been seen in western Switzerland, but recently appeared in Bern and Zurich and was connected to severe intoxication and deaths in Europe . Other explorations of the illegal substance market during the Covid-19 pandemic outbreak in Switzerland showed similar results . Indeed, while triangulating analyses of wastewater, used syringes, and drug seizures, interviews with the heads of five regional drug squads, and analyses of purchases on darknet sites selling drugs, we showed a rather stable situation and limited impact of the pandemic on substance supply, prices, and quality, except for a cannabis resin shortage .
Recent reports from the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) and the European Union Agency for Law Enforcement Cooperation (Europol), and from the United Nations Office on Drugs and Crime (UNODC) have shown heterogeneous situations at both the country and substances levels [18, 19]. While some countries had temporary shortages, price increases, and decreases in purity for some substances, others, such as Switzerland, had more stable situations. Shortages of cannabis resin were also seen in other European countries [19, 20]. Despite this, analyses of specialized darknet platforms showed a significant increase of cannabis purchase during the Covid-19 outbreak , a trend also found in the United Kingdom, Germany, the Netherlands, and France .
At this stage of the pandemic, it seemed that importation and supply networks were little affected and continued to operate as usual in Switzerland (with some occasional latency, which eventually may have affected the quality and price). It also appeared that the market of substances imported from far countries like Afghanistan (for heroin) and Latin America (for cocaine) was less impacted than was the market of substances imported from near countries such as Morocco (hashish) and Spain (herbal cannabis). The pandemic in Spain, which was among the most serious in Europe at the time, may explain these unexpected findings. It might also be that the cocaine and heroin markets are strongly established and sufficiently well-organized enough to overcome law enforcement obstacles such as reinforced border controls, drastic decreases in goods and people transportation, population (consumer) lockdowns, social distancing measures and other controls. Organized crime groups remained resilient and adapted their modi operandi to the current situation, further exploiting secure communication channels and adapting transportation models, trafficking routes and concealment methods .
Questions investigating the impact of the pandemic on participants’ substance use also indicated minor impact overall. The quantitative and the qualitative data were in the same direction. Substance use was estimated as usual by most, trending toward decrease. Similar findings were seen in online surveys among substance users in Switzerland , Europe , and Canada . In those countries, decreases were more frequent for stimulants (e.g. cocaine, MDMA), mainly due to closure of the night scene.
Analyses of correlations of the impact of the pandemic with the different substances indicated that users generally decreased or increased all substances, and did not transfer from one substance to another. However, correlations of prescription drugs and ‘other’ drugs with heroin, cannabis, and alcohol were significant at wave 2, but not at wave 1, suggesting that some transfers from one of these drugs to another might have cancelled the correlations found at wave 1. Some were concerned that shortages in heroin supply would lead to the consumption of other substances, such as fentanyl and its derivatives, or resold pharmaceutical products, such as benzodiazepines and buprenorphine . It seems that this was not the case in Switzerland, or at least that it was only temporarily scarce. Similar patterns were also seen in the Czech Republic .
The impact of the pandemic on participants’ social situation and health was appraised as low to medium in both the qualitative and the quantitative data. There were no significant differences across the two quantitative waves, despite a slight trend toward decreased impact. However, there was relatively high variability in the scales that was captured in semi-directive interviews as well. A minority of participants indeed reported higher impact related to anxiety, boredom, depression and lack of social contacts. Multivariate analyses also nuanced overall findings and showed that the impact was more important for those who were female, younger, and using a low number of substances, and less important for those who were male, older, and using multiple substances. A recent study showed similar patterns in France, where the impact on substance users’ health and social situation was heterogeneous and depended on substance use patterns and socio-demographics. A particular burden on mental health was also noticed there .
Correlations of the influence of the pandemic on substance use with social situation and health showed contrasting findings at wave 1, with higher impact on social and financial situation related to decreases in cocaine and cannabis use, and higher impact on mental health related to increases in heroin use. These findings might indicate that the social and financial situation during wave 1 (with harder lockdown measures) might have had a stronger impact on cocaine and cannabis use. This could be due to fewer social interactions and occasions to use. Similar findings were observed in Europe  and among recreational users in Switzerland . It could also be related to lower financial resources to invest in substances, as seen in France . Conversely, the positive correlation of heroin use with mental health impact might reflect the use of heroin to cope with mental health issues triggered by the pandemic and lockdown measures. Coping might also explain the significant correlations of stress/anxiety, mental health, and physical health in general with increases in prescription drugs use and alcohol. Several studies pointed to increased use of heroin, alcohol, and prescription drugs, such as benzodiazepine, related to mental health issues and coping behaviours [23, 26–28].
The last point addressed in our study concerns the measures and adaptations taken by health care and social institutions and potential suggestions from participants. Qualitative findings indicated that measures taken and adaptations were globally appreciated and valorised by participants. Hygiene measures and health recommendations, such as staying at home, frequently washing hands, and respecting social distancing seemed to be accepted and followed by most participants. Among the suggestions provided, most wanted additional information and more drug consumption rooms. In one online survey on the impact of Covid-19 on youth mental health, substance use, and well-being in Canada, respondents requested that high-quality information about Covid-19, mental health and substance use supports be made available to help them .
Adaptations made at ATC included extending opening hours to regulate patient flows, decreasing frequency of individual visits by allowing take-home and home delivery of OAT doses and telehealth services. We recorded only one criticism related to a change in treatment route; this patient used to receive diacetylmorphine by injection, but had to switch to oral diacetylmorphine since he received treatment at home. Injections are not allowed outside the hospital due to lack of monitoring of clinical parameters and emergency care. All other comments were favourable toward the adaptations implemented. Beyond the mandatory changes required by the urgency of the Covid-19 crisis, one ponders which of those measures might be sustained in the long run. Similar measures were implemented elsewhere [29, 30]. Additional measures were also proposed, such as improving addiction treatment access using telehealth encounters for OAT induction [31, 32], substance use decriminalization , and safe supply of opioid  and other substances, including stimulants . Further research should investigate their potential impact on substance use behaviours, substance use disorder outcomes, treatment retention, intoxications, and mortality, as well as long-term physical, mental, and social outcomes.
In the context of the outbreak of Covid-19, we opted for a design inspired in rapid assessment processes [11, 12] and combined quantitative and qualitative methods to collect first-hand observations by substance users purchasing drugs in the illegal market. This methodology quickly furnished valuable findings directly reported to the clinical staff and other local and national institutions [36, 37]. Nevertheless, it was accompanied also by several scientific limitations. First, we used anonymized questionnaires in the quantitative phase of the study in order to avoid patients refusing to provide written records of sensitive illegal activities. As a result, we were unable to conduct follow-ups assessing the evolution of individual situations over time via more advanced longitudinal statistical methods. This limit was partly offset with a qualitative follow-up of a sub-group of participants. Also, the high participation rates overall, along with the high follow-up rate in the qualitative phase lend strength to the research. One limitation of the qualitative part of the study was the absence of audio recording and verbatim transcription. Our thematic analysis relied on interview notes, which might have introduced bias. Additionally, it should be noted that our findings are limited by our sample, which was comprised of patients receiving OAT in the Addiction Treatment Centre of a University Hospital in Switzerland. Our country is among the most wealthy in the OECD and has a high performing health system , including a universal mandatory health insurance system with virtually 100% coverage . OAT is included in this coverage, and most patients also receive social welfare support. The participants in this study may have higher social integration, more frequent clinical follow-up, and have lower risk of opioid withdrawal or other substance-related consequences, than do others using substances but not receiving OAT. Recent studies suggest that those who are more vulnerable, such as the homeless  and those who have lower socioeconomic status [41, 42], are more affected by the pandemic. Further empirical research should address the plight of these populations. Finally, our analysis focused only on the first wave of the Covid-19 outbreak. Future research should investigate the impact of subsequent waves and the long-term effects of the crisis on the illegal substance market and on the health and social situation of drug users.