This study yielded unique findings with regard to Irish GP views on decriminalisation of cannabis and the medical use of cannabis (CTP). The majority of GPs did not support the decriminalisation of cannabis, but male respondents were significantly more likely to support this drug policy approach than their female counterparts. This majority view is contrary to current Irish government policy on the issue. Nearly 60% of GPs supported the legalisation of cannabis for medical use with older (>50) and male GPs more likely to favour this approach. In contrast to the view on decriminalisation, this majority view supports Irish government policy on CTP.

In 2000, the Irish Drug Related Knowledge, Attitudes and Beliefs survey found that males reported greater use of cannabis and knowledge of cannabis users than females [34]. This study, while dated, indicated that only 24% were in favour of legalisation of cannabis. Of interest is that the majority of GPs trained to a more specialist level in addictions supported decriminalisation (54.1% p = 0.021). This may in part be due to their experience treating patients with opioid dependence in particular injecting drug users. In this patient cohort, cannabis use is often considered a secondary issue when managing the high-risk behaviour and health issues associated with injecting drug use. In contrast, in terms of gender, regression analyses revealed that females were less likely to agree that cannabis should be decriminalised. Prevalence data in Ireland has reported little change in women’s rates of cannabis use, with prevalence rates highest among men and younger adults aged 15–34 years [35]. Research shows that individuals with personal experience of cannabis use are more inclined to be in favour of legalising [36]. According to the National Advisory Committee on Drugs and Alcohol (NACDA) in 2012 general population survey, the majority of respondents agreed with medical use of cannabis and disagreed with recreational use of cannabis. This is consistent with the drug policy approaches supported by Irish GPs in this survey.

Both genders of GPs in this study voiced concerns that decriminalisation would lead to increased use and the misuse of prescribed versions if available. Hall and Lynskey [37] speculate that potential effects of legalising recreational cannabis use, while substantially reducing the price, increasing excessive use and related harms, may also increase the number of new users. However, of interest, is recent reporting of a great overlap between medicinal and recreational cannabis use in the USA [38]. Regulating the cannabis market via prohibition and decriminalisation has a marginal effect on onset of cannabis use and population consumption rates [6]. Yuyan et al. [39] in their review of 38 countries indicated that cannabis liberalisation with depenalization and partial prohibition policies was associated with higher levels of regular cannabis use among adolescents. This is concerning given a recent Irish study [40] which underscored the relatively low levels of adolescent-perceived risk of mental and physical health problems with use of the drug. According to Eurobarometer [41], Ireland has the highest number of young people who have used cannabis in the past year (28%), compared to a Europian Union (EU) average of 17%; 58% of Irish youth have never taken cannabis, which in 2014 is third lowest in Europe and well below the EU average of 69%. Overall, 46% of young Irish people consider regular cannabis use to be high risk, compared to an EU average of 63%. The Eurobarometer in 2014 [41] also reported that 56% of Irish 15–24-year-olds were of the view that the cannabis market should be regulated, which is almost a reverse position of the EU average, where 45% said cannabis should be regulated, and 53% said it should continue to be banned.

GPs in this national study agreed that cannabis use has a significant effect on patients’ mental health and increases the risk of schizophrenia. Kondrad and Reid [25] have reported majority agreement of US physicians in Colorado regarding the serious mental and physical health risks of cannabis. Irish GPs in this study underscored their experience of the significant adverse effect on patient mental health and risks of schizophrenia in young users. Heavy use of cannabis at an earlier age is reported to heighten risk of dependence, depressive disorders, psychosis, suicidal ideation, development of schizophrenia and related negative social consequences [17]. This contributes to the debate around the cannabinoid hypothesis of psychosis, for example that exposure to cannabis and cannabinoid agonists is associated with psychosis outcomes through activation of CB1R [42–44]. However, to date, a causal relationship has not been established [4].

Kondrad and Reid [25] in their 2013 study of physician experiences and attitudes to medical cannabis reported that nearly half of participants did not support CTP and that only a minority thought therapeutic use of cannabis conferred physical and mental health benefits. Israeli practitioners in 2015 voiced partial acceptance for therapeutic use, and generally agreed that CTP could be helpful for chronic and for terminally ill patients [26]. However, oncologists and pain specialists did not agree unanimously that medical cannabis can undermine mental health, whereas other physicians did [26]. CTP is driven by public approval without scientific data routinely required to justify new medication regulation [45, 46]. In 2005, US physicians reported less support of CTP than the public [24]. Irish GPs who reported practicing in a non-deprived area in this study were more likely to agree that cannabis has a role in pain management compared to those who reported working in a deprived area. Level of training for this Irish sample reflected that a greater percentage of those participants with level 1 substance misuse training agreed/strongly agreed that cannabis should be legalised for medical use. While the clear majority of this group supported the role of medical cannabis in pain management, treatment of multiple sclerosis and palliative care, they were statistically less supportive than those without this training. Irish GPs aged 30–50 years were more likely to disagree that cannabis can have a role in the treatment of multiple sclerosis compared to those not in that age group. Kondrad and Reid [25] found that age was significantly associated with the recommendation of medical cannabis. They also found no significant association with physician gender, years in practice, or type of licence and recommendation of medical cannabis. In contrast, this study found that female GPs in Ireland were less likely to agree that cannabis should be legalised for medical use compared with males, and were also less likely to agree that cannabis has a role in palliative care or a role in the treatment of multiple sclerosis than males.