‘Medical’ marijuana is incompatible with mental health promotion

To the Editor

The recent public debate around the legalization of medical cannabis has put the medical profession in Australia on the back foot. Among medical practitioners, psychiatrists as a group have a responsibility to the general public to advocate against its introduction in this manner. There is overwhelming evidence regarding the harms associated with cannabis, and there is no guarantee that the use of extracted cannabinoids would remove these long-term risks, particularly with regard to dependence and psychosis (Borgelt et al., 2013). Furthermore, the potential for marijuana to be misused is not obviated by its medicalization. This represents a false assumption that medicalization would ensure sufficient oversight in order to prevent its misuse.

There have been calls for products derived from cannabis to be made more readily available for the management of particular conditions, including palliative care and intractable childhood epilepsy (Martin and Bonomo, 2016). However, there is clearly potential for long-term dependence and other psychological harms given what is already known about cannabis. The history of our own profession ought to provide a cautionary tale in itself regarding the problems associated with granting approval for the use of a substance with the expectation that its use will remain contained. The current misuse of dexamphetamine is an example of this potential hazard. Although dexamphetamine was originally introduced for the specific treatment of attention deficit and hyperactivity disorder (ADHD) in children in the 1990s, its use has since expanded (Berman et al., 2009). In addition to its increasing availability as an illicit drug, it is now purported to have an evidence base for the treatment of a range of conditions outside its initial indication, including the management of adult ADHD. It has also been used as off-label prescriptions for the treatment of various mood disorders as well as dementia (Berman et al., 2009). Without doubt there are many instances in which this prescription would be for dubious indications. There is a recognition in the medical literature that significant psychological adverse events, including stimulant-induced psychosis, can be precipitated by dexamphetamine prescription (Berman et al., 2009).

Similarly, it can be anticipated that if introduced, the indications for the use of medical cannabinoids would expand well outside of the initial indications. Hence, the medical profession cannot justify the use of medical cannabinoids that would be associated with an iatrogenic risk of serious adverse psychological events.

The use of medical cannabinoids for any purpose, including research under closely observed conditions, is incompatible with mental health promotion.