Author of new mephedrone study discusses his findings

A small study published in Addiction last month analyses the cognitive effects of the synthetic stimulant mephedrone.

Before it was reclassified in 2010 as a Class B drug, mephedrone was legal, inexpensive and quite easily found online- often as ‘plant food’. The study, notes its investigators, is ‘the first to document the acute and long-term effects associated with mephedrone use’ and therefore presents itself as ‘an important public health issue’.

The report assessed 20 individuals who regularly used mephedrone (mean age 21.6 years, 55% male) against 20 who had not used the drug in the previous six months (mean age 21.6 years, 70% male). The study showed that regular users of mephedrone demonstrated increased levels of cognitive impairment, psychosis and depression when compared to their non-using peers. 

In line with the author’s expectations, the study also showed that mephedrone induced craving that was ‘binge-like’. The study found that users had significantly higher scores in total schizotopy, cognitive disorganisation and depression than the control group. Mephedrone users’ prose recall scores were also significantly worse than their non-user peers.  

As well as using the Beck Depression Inventory and the Oxford-Liverpool Inventory of Feelings and Experiences (O-Life), researchers also used a ‘Mephedrone and Future Use Study’ to ask users about their buying and using habits.

 This important questionnaire revealed that users were most likely to buy a ‘hypothetical new legal high’ if it was pure, lacked harmful short-term and long-term effects and if it had received good reviews from friends or the internet.  100% of users said that, since mephedrone had been made illegal, they were now purchasing the drug on the street. 55% of the subjects also said that their use of other drugs had increased since the reclassification of mephedrone. 

The lead author of the study is Tom Freeman, a PhD candidate in psychopharmacology in the  Clinical Psychopharmaclogy Unit at University College London. He discusses some of his findings below. 



Abigail Jones: Your study records that mephedrone has some undeniable psychological effect on users - that mephedrone users, when ‘coming down’ from it, had depressive scores which were higher than those who did not use mephedrone.  It would be generally correct to say that mephedrone makes people more depressed?

Tom Freeman: Depression scores were taken from mephedrone users 6-7 days after they had used the drug.  It is unlikely that these scores represent a comedown after this amount of time.  However the results cannot speak to the question of causality since this was a cross sectional study. The best way to state to the results would be 'mephedrone use is associated with increased levels of depression'

AJ: The main aim of your study is to fill a certain gap in drugs research: there has, you say, been no study of the cognitive effects of mephedrone. Why do you think that there has been an absence of such research up until now, and what effect do you think it has on mephedrone users’ habits?

TF: New drugs like mephedrone might be short lived and it is difficult to predict their impact.  Academic research typically takes a lot of time (years) in terms of planning, funding, ethics, peer reviewed publication, and may not well suited to adapt to rapid changes in the drug market.  Researchers may be put off investigating new drugs for the risk involved when the future of a substance is so hard to predict.  New legal highs are challenging across the board in terms of detection and prevalence, knowledge of their effects and adequate advice, and attempts to restrict their sale/control their use.

AJ: Mephedrone has been illegal since 2010. A questionnaire that was part of your study revealed that mephedrone users, when considering whether or not to buy a ‘hypothetical new legal high’, would rate the opinions of their friends and internet-based reviews more highly than scientific research. Why do you think this is? 

TF: The lack of scientific research and adequate advice from FRANK etc means that the internet and friends are probably the only viable option for advice.  However by drawing attention to the importance of these mediums, I hope that efforts will be made to improve the quality of information available to potential drug users.

AJ: Some mephedrone users have reported heart palpitations, shortness of breath and ‘wheezing’.  Your analysis is geared toward an analysis of the cognitive effects of mephedrone, rather than the physical, but did your mephedrone participants report or display any circulatory or respiratory changes due to the drug?

TF: Two of the participants in the study reported having experienced chest pains in the week following use.  However, the study design (n=20 users, n=20 controls, both tested twice) meant that it was most adequately suited to address cognitive and subjective effects of the drug, which had never been investigated before.  Questionnaire based studies with larger samples may be better suited to addressing the prevalence of side effects.

AJ: Finally, is there anything you want to say about your findings and/ or the uses of research like this?

TF: As a final point I think more effort should be made to ask drug users why they take drugs.  This would be a sensible way to inform 'top down' changes such as reclassification of substances.  If for example cannabis users themselves will not change their use in response to the drug being class A/B/C there may be little point in making reclassification.