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DOI: https://doi.org/10.58248/RR16  

Overview  

POST has published briefings on the use of psychedelics to treat depressive disorders, anxiety disorders, eating disorders and PTSD. This is part of our wider work on the use of psychedelics to treat mental health conditions. POST will publish a major briefing on this later in 2024.   

This briefing focusses specifically on addictions and covers:  

  • the different types of addictions to substances and addictive behaviours 
  • existing treatments for addictions 
  • research into the use of psychedelics to treat addictions  

What is addiction? 

Addiction, as defined by international medical diagnostic guidance, is a compulsive pattern of substance use or behaviour characterised by impaired control, significant impairment in functioning, and persistent use despite adverse consequences. Biological, environmental and social factors also influence susceptibility and risk to addiction.  

Addiction can be divided into: 

Addiction is centred in the brain’s ‘reward system’. It involves complex interactions between brain regions and chemicals called neurotransmitters. Dopamine, a neurotransmitter associated with pleasure and reward, and others including endorphin and serotonin systems, are involved in the biology of addiction.  

When a person engages in addictive behaviours (such as substance use or gambling) the brain’s neurotransmitters change and this leads to feelings of pleasure or reward, which can reinforce the behaviour. Over time the brain adapts, reducing neurotransmitter release in response to the addictive stimulus (even at the same doses), leading to tolerance.  

In the long-term, changes occur in specific brain regions and networks. This can impair decision-making and impulse control and lead to continuation of addictive behaviours. These long-term changes are also influenced by biological, psychological and social factors that can play a role in an individual’s development and maintenance of addiction, and their vulnerability to relapse. 

An academic review has described the risk and protective factors linked to drug abuse. 

How is addiction currently treated? 

Addiction treatment uses a comprehensive approach that recognises the diverse nature of addiction, encompassing substance use and behaviours.  

Treatment strategies are tailored to individual needs and circumstances, focusing on the biological, psychological and social factors contributing to addiction. Generally, the approach is psychological and social support, with additional drug treatment. 

  • Medication-assisted treatment may be used for certain substance dependencies to manage withdrawal symptoms (the symptoms somebody experiences when a drug is suddenly stopped after a lengthy period of regular use), reduce cravings, or block the effects of drugs. Alongside medication, various forms of psychotherapy are commonly used, including: 
  • cognitive-behavioural therapy (CBT), 
  • motivational interviewing 
  • dialectical behaviour therapy (DBT) 
  • psychodynamic therapy 

These therapies aim to address underlying psychological issues, modify maladaptive behaviours and develop coping strategies. 

  • Supportive services, such as counselling, group therapy, and peer support groups like Alcoholics Anonymous, Narcotics Anonymous and Gamblers Anonymous, play a role in providing ongoing encouragement, accountability and a sense of community.  
  • Holistic approaches integrating physical wellness activities, mindfulness practices, and vocational or educational support are increasingly used to promote overall well-being and prevent relapse. 

There is consensus that addiction treatment should acknowledge the individual nature of addiction experiences, and recognise that factors such as genetics, co-occurring mental health disorders, trauma history, and social determinants of health significantly influence treatment outcomes. Thus, treatment plans that are flexible and collaborative, evolving to meet the changing needs and goals of each person, are most likely to succeed.  

Research into the use of psychedelics for treatment of addiction 

Before the introduction of legislation that limited access to psychedelics, research groups published data indicating a possible role for psychedelic-assisted psychotherapy for treatment of addictions, including alcoholism. This section focusses on contemporary research. A comprehensive review article covering the historical research trials and the present era is available here.  

To assess the effectiveness of any drug, researchers use a study method to minimise bias called a randomised controlled trial. Participants are split into two groups and do not know which group they are assigned to:  

  • one group receives the drug treatment  
  • one group receives a placebo (and is called the control group) 

In the context of psychedelic treatment, adhering to this process can be challenging because it may be obvious whether an individual has received either the drug or the placebo. Knowing this can introduce a form of bias that may affect the outcome.   

In some trials researchers choose to use an active placebo as a control. This is a drug chosen because it mimics some of the effects of the drug being tested, to reduce the risk of risk participants knowing if they have received the psychedelic drug being tested or not.  

So far, one clinical study has reported some evidence that psilocybin can be effective in treating alcohol addiction. More studies using high quality methods and large enough groups of participants are needed to confirm this.  

This is an active research area, and ongoing research on several psychedelic drugs is detailed below. 

Psilocybin 

Alcohol use disorder 

Two studies have shown some evidence that psilocybin is effective for people with a diagnosis of alcohol use disorder.  

Participants in the smaller study knew they were receiving psilocybin, whereas in the larger study both participants and the researchers were ‘blinded’ and did not know who received the psilocybin. In this trial participants received either an active placebo or psilocybin.  

Nicotine dependence 

Psilocybin has also been studied for nicotine addiction. Nicotine is the predominant addictive component of tobacco. 

Other treatment options for nicotine addiction – including nicotine replacement therapy, or other drug treatments, in addition to psychological therapies – can have effectiveness much lower than this. However, the study design in this case means the findings should be interpreted with caution until more robust data is collected. Such a trial is ongoing through Johns Hopkins University in the US. 

Gambling addiction 

Psilocybin therapy is also being researched as a possible treatment for gambling addiction. A new pilot brain imaging and clinical research study was announced by Imperial College in 2023. The study will collaborate with the specialist NHS Gambling Clinic. 

Other addictions  

Early clinical research is underway to examine if psilocybin therapy can treat other addictions including opiate, cocaine and methamphetamine use disorder. These studies are taking place across the UK, Europe, Canada and the US in universities and pharmaceutical companies.   

Ketamine 

Ketamine is also being studied for its potential to treat alcohol use disorder. 

There is an ongoing larger UK-based phase III clinical trial (MORE-KARE) which aims to add more data to the evidence base across several sites treating alcohol dependence with ketamine-assisted psychotherapy.  

MDMA 

In a proof-of-concept study on alcohol use disorder (AUD), the safety and tolerability of MDMA was evaluated in 14 patients. The study also looked at psychological and physiological outcomes. All participants tolerated MDMA well, and no severe adverse events were reported. Additionally, at 9 months after the study, participants’ average alcohol consumption reduced from 130.6 units per week before the trial to 18.7 units per week.  

Another trial is currently underway to assess the use of MDMA-assisted psychotherapy for patients with opioid addiction following childbirth.  

Are psychedelic drugs addictive? 

Research has examined whether psychedelic drugs are themselves addictive. They are not generally considered to be addictive (called abuse potential in research), although there are concerns about ketamine.  

However, other harms have been reported in the research literature and will be discussed in a POSTnote that will be published later in 2024.   

Ongoing and future research 

In addition to the planned studies outlined above, there is significant research interest in ibogaine, another psychedelic. Trials have been announced focussing on ibogaine for alcohol dependence, and for both opioid withdrawal and dependence. Clinical research is underway on short-acting psychedelics including 5-meo-dmt for alcohol dependence. 

Recent government funding has supported clinical and mechanistic research of psychedelics to treatment substance addiction. Most studies are undertaken in the biotechnology and pharmaceutical sectors and in academic centres. In the UK these include Imperial College London, University College London, Exeter University and King’s College London. 

Further reading 

Acknowledgements 

POST is grateful to Dr Stephen Naulls, Clinical Research Fellow at POST, for researching this briefing.  

POST would like to thank Professor Joanna Neill (Professor of Psychopharmacology, University of Manchester), Dr Rayyan Zafar (Centre for Psychedelic Research & Neuropsychopharmacology, Imperial College London) and Professor James Stone (Brighton and Sussex Medical School) who acted as external peer reviewers in preparation of this article.  

Photo by: (© By New Africa  – stock.adobe.com).

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