Since the early 1970s concerns have been recurrently expressed that cannabis products are becoming more potent (and therefore more harmful to health) than was previously the case (Hall & Swift, 2000; McLaren et al., 2008). Regular monitoring of cannabis products in the USA indicates that THC content has increased from less than 2% in 1980 to 4.5% in 1997 (ElSohly et al., 2000) and more recently to 8.5% (ElSohly, 2008; ONDCP, 2007; see also Chapter 3). THC content also increased in the
Netherlands between 2000 and 2005 (Pijlman et al., 2005), and may also have increased in other European countries - although it is uncertain by how much in the absence of time series data on THC in representative samples of cannabis products (EMCDDA, 2004). Increases in potency have probably resulted from a combination of selective breeding of higher potency plants and a shift to indoor cultivation using the sinsemilla method. All of these trends have been encouraged by the illegal status of the product, which favours the production of more concentrated forms.
The effect of any increase in the potency of cannabis products on health will depend on the extent to which users are able to offset the effects of increased THC by titrating the dose of THC that they obtain (Hall & Swift, 2000). One can conjecture about some of the possible effects of increased cannabis potency. Among naive users, higher THC content may increase the likelihood of adverse psychological effects, such as anxiety, depression and psychotic symptoms. These may discourage firsttime users from continuing to use the drug. Among continued users, increased potency might increase the risk of dependence. If regular users fail to fully compensate for increased potency by titrating their dose, this would increase the risk of psychotic symptoms in vulnerable users. Any adverse effects of cannabis smoking on the respiratory and cardiovascular systems may be reduced if regular users are able to titrate to a desired dose of THC. Increased potency could also plausibly increase the risk of road traffic crashes if users do not titrate and drive while intoxicated.
The increased THC content of cannabis may not be the only relevant consideration; changes in the ratio of THC to CBD in cannabis may also be important. Potter et al. (2008) found that cannabis grown using the sinsemilla method has the highest THC: CBD ratio and cannabis resin the lowest. Given suggestive evidence that CBD has anxiolytic and anti-psychotic properties (Morgan & Curran, 2008), research needs to investigate the effect that changes in the THC: CBD ratio have had on the risk of adverse psychological effects from using cannabis.
Was this article helpful?
Tips And Tricks For Relieving Anxiety... Fast Everyone feels anxious sometimes. Whether work is getting to us or we're simply having hard time managing all that we have to do, we can feel overwhelmed and worried that we might not be able to manage it all. When these feelings hit, we don't have to suffer. By taking some simple steps, you can begin to create a calmer attitude, one that not only helps you feel better, but one that allows you the chance to make better decisions about what you need to do next.