‘It’s an exciting time to be researching and writing about drugs’

In the book you discuss the effects of, and myths associated with, 24 different drugs including legal substances like alcohol, coffee and cigarettes, and illegal substances including cannabis, MDMA and cocaine. I'm guessing it wasn't too hard finding research on legal drugs, but was it a challenge to find quality research on the effects of the illegal substances? How was the research conducted ethically and legally?
You're absolutely right that it's far more of a challenge to conduct research into illicit substances. But not impossible. There are some labs round the country, and across the world, that have licences and approval to administer illicit substances like MDMA, cannabis (usually as the constituent chemicals such as THC or CBD), or psilocybin (the psychedelic substance found in magic mushrooms). This isn't the type of research I've done in my academic study though. I use large datasets where individuals are followed up over time, and what they choose to do is noted. Then you can see whether behaviours like substance use are linked to a higher likelihood of later developing mental health problems, for example. The problem with this is that these behaviours are not randomised or controlled, so there may be other differences between the groups, which need to be taken account of.

And of course there's a risk that people aren't honest about their illicit drug use, because of the legal status of drugs maybe. Having said that though, even where substances are legal research can be hard to do. If you want to (for example) understand the long-term effects of using alcohol, you still can't do a randomised controlled trial, it would be unethical and impractical, even if you could get people enrolled in the study. So ultimately you're still left to observe what people choose to do, and try and infer from that. There's still a surprisingly large amount we don't know about the effects of alcohol and tobacco, and a whole host of myths and misconceptions that exist around them.

Are there any general effects on psychological functioning or mental health from the drugs you explore, or do they differ so widely between substances that there's little generalisation to be done?
'Drugs' are often lumped together as one thing, but actually they can have a variety of different effects. All of them are 'psychoactive' in some way, by definition, so all have an effect on things like perception or cognitive ability, but what that effect is can vary. Many, but not all, of the substances in the book have a risk of dependence from heavy regular use. And a lot of them, across various different types, seem to be associated with poorer mental health. But why this is isn't clear. Could taking a psychoactive substance regularly increase the risk of mental health problems? Or might people who are struggling with their mental health turn to psychoactive substances because of that? It's very difficult to be sure.

Did anything surprise you when you were researching content for the book?
Loads! There were a number of substances I knew very little about when I started. It was great speaking to researchers all over the world to find out about substances that aren't that widely used in the UK but are popular in other places. I spoke to Australian researchers about amphetamine, and USA researchers about kratom. It was also really interesting reading about the histories of some of the substances in the book. And just how many drugs we think of as 'recreational' also have, or have had in the past, medical uses. From ketamine to opioids and benzodiazepines. And now with cannabis and psychedelics being investigated for potential therapeutic uses, it's an exciting time to be researching and writing about drugs.

What do we not know about drugs at the moment that you'd like to know?
There's so much we don't know. I'm really excited to see the results of some of the studies looking at whether drugs like MDMA, ketamine, or psychedelics could be useful as part of psychotherapy. I'd also really like to know why some individuals develop problems from their drug use, and what we can do to identify who is particularly at risk, to prevent this happening, or better help those individuals who are struggling.

What advice would you give to someone considering experimenting with drugs?
No drug use is without risk – there's no such thing as a safe drug, this is true of legal and illicit drugs. So you are better off not taking a drug, if you want to avoid any risk of harm. And certainly if you're a teenager and your brain is still developing, the risk of harm is higher still. But if you are determined to take a substance there are ways to reduce the risks. Start with a small dose, particularly if you've never taken the substance before – it's much better to underestimate than overestimate a dose. If the substance is illicit there are big risks due to that – you can't be sure that what you're taking is what you think it is, it could be cut with other things, it could be something completely different, and the dose could be very variable. There's no quality control on the illicit drugs market. Consider getting your drugs tested before you take them: if you live in Wales you can post samples to WEDINOS, or there are services like the Loop at music festivals, and occasionally in city centres. But testing drugs cannot necessarily tell you everything – drug test kits only test for certain specific things, so if there's something else risky in the substance it won't tell you that. The other advice I would give would be to make sure you take substantial breaks between uses. Give your body time to recover, and reduce the risk of developing dependence. This advice applies to alcohol too!