Cannabis and Pain

Chronic pain conditions are the most prevalent form of disease in many countries. In the US, the American Pain Foundation estimates that 76.5 million people suffer from persistent pain. With few alternatives and a lack of safe and effective treatments for disabling pain, millions will continue struggling to function in their daily lives. Many people suffering from chronic pain have turned to medical cannabis, but the practice is still frowned upon by some lawmakers.

Montana recently passed a law to restrict the number of people living with chronic pain from taking part in the state’s medical cannabis program. Some states, such as New Jersey, arbitrarily prohibit the use of medical cannabis for chronic pain due to a failure by public officials to grasp the therapeutic benefits in this area.

Several new scientific articles examined the ability of cannabis and cannabinoids to treat pain. Clinical trials using cannabis in various forms (smoked, extracts, oral THC, synthetic analogues) were reviewed by different research teams. Three recent reviews of the clinical trials on cannabinoids and pain, demonstrate that cannabis and cannabinoids are effective for treating certain types of chronic pain with acceptable side effects.

After reviewing the scientific evidence, researchers from Canada concluded, that:
overall the quality of trials was excellent. Fifteen of the eighteen trials that met inclusion criteria demonstrated a significant analgesic effect of cannabinoid as compared to placebo, several reported significant improvements in sleep. There were no serious adverse effects. Adverse effects most commonly reported were generally well tolerated, mild to moderate in severity and led to withdrawal from the studies in only a few cases (Lynch et al).

These researchers go on to say:
this systematic review of 18 recent good quality randomized trials demonstrates that cannabinoids are a modestly effective and safe treatment option for chronic non-cancer (predominantly neuropathic) pain (Lynch et al).

Another research group from the University of Pennsylvania published a similar review concluding that:
there is strong evidence for a moderate analgesic effect in peripheral neuropathic and central pain conditions, and conflicting evidence for their use in nociceptive pain. For spasticity, most controlled studies demonstrate significant improvement. Adverse effects are not uncommon with cannabinoids, though most are not serious and self-limiting.

Both groups call for trials with cannabis or cannabinoids for the treatment of pain. Furthermore, a review on the treatments for HIV neuropathic pain concluded that:
evidence of efficacy exists only for capsaicin, smoked cannabis and rhNGF. However, rhNGF is clinically unavailable and smoked cannabis cannot be recommended as routine therapy (Phillips et al).

Meaning, the only medications that have been shown to effectively alleviate HIV/AIDS neuropathic pain are not available on the market. Notably, smoked cannabis was shown to be effective for the treatment of HIV neuropathy, a condition that affects upwards of 40% of the estimated 33 million people currently living with HIV (Phillips et al).

Neuropathic pain, pain from multiple sclerosis, various chronic pain conditions, and often cancer pain are routinely treated with opiates, anticonvulsants, and antidepressants (Russo 2008), but are difficult types of pain to treat. Cannabis extracts have been shown to treat difficult-to-manage pain in patients that is non-responsive to more conventional treatments. Furthermore, medical cannabis researcher Ethan Russo suggests that the use of Cannabis preparations offers "side benefits" due to the presence of additional compounds:
These include anti-emetic effects, well established with THC, but additionally demonstrated for CBD (Pertwee 2005), the ability of THC and CBD to produce apoptosis in malignant cells and inhibit cancer-induced angiogenesis (Kogan 2005; Ligresti et al 2006), as well as the neuroprotective antioxidant properties of the two substances (Hampson et al 1998), and improvements in symptomatic insomnia (Russo et al 2007).

The therapeutic benefits of cannabis for pain are evident both scientifically and anecdotally. Public officials should develop policies that correspond to such benefits and stop restricting access for people with debilitating pain.

This guest blog was written by Jahan Marcu, a researcher in the field of cannabinoid pharmacology, vice-chair of the medical and scientific advisory board of Americans for Safe Access, and science editor at He was part of a research team which published a study in the journal of Molecular Cancer Therapeutics on how CBD can enhance the anti-cancer effects of THC in aggressive brain cancer in 2010.