• A THC/CBD-containing oromucosal spray identified as nabiximols (Sativex ©) 
• An oral solution of CBD (Epidiolex). 
• A tablet of a synthetic THC analog (nabilone)  

2.2. Extemperaneous mixtures containing defined doses of cannabinoids extracted from the cannabis plant:Oral solutions and tablets with THC (Dronabinol ©)  

It is notable that most randomised controlled trials (RCT’s) for pain mangement have been conducted with cannabinoid-based medicines and not with medical cannabis.  

Methodology and politics: In the pain community, there are highly polarized views about the indications for use, as well as the efficacy and safety of cannabinoid-based medicines and medical cannabis. Currently, there are a limited number of RCT’s for various pain-related conditions, with the numbers of trials exceeded by the number of systematic reviews. Conclusions of systematic reviews, either positive or negative are the foundation of evidence-based medicine and should be the driver for patient care. Divergent conclusions of SRs on the efficacy of cannabis-based medicines in chronic pain may be attributed to analyses of different studies based on different inclusion criteria, variable study duration, and differing attributes of benefits and risks. A recent systematic overview of systematic reviews concluded that current systematic reviews are mostly lacking in quality and cannot provide a basis for decision-making. The same author group concluded that even when including their own systematic review of RCTs, the evidence neither supports nor refutes claims of efficacy and safety for cannabinoids, cannabis, or CBM in the management of pain. Unfortunately, adhering to this rigorous methodology is not helpful in clincial practice. In my lecture I will discuss the evidence available for use (e.g. neuropathic pain) and not for use (e.g. cancer pain insufficiently controlled by opioids) of cannabinoid-based medicines and medical cannabis in general. In addition, I will list the evidence available on harms of cannabinoid-based medicines and medical cannabis.

Although placebos have long been considered a nuisance in clinical research, today they are an active and productive field of research and, because of the involvement of many mechanisms, the study of the placebo effect can actually be viewed as a melting pot of concepts and ideas for neuroscience. Indeed, there exists not a single but many placebo effects, with different mechanisms and in different systems, medical conditions, and therapeutic interventions. For example, brain mechanisms of expectation, anxiety, and reward are all involved, as well as a variety of learning phenomena, such as Pavlovian conditioning, cognitive and social learning. There is also some experimental evidence of different genetic variants in placebo responsiveness. The most productive models to better understand the neurobiology of the placebo effect are pain and Parkinson’s disease. In these medical conditions, the neural networks that are involved have been identified: that is, opioid, cannabinoid, cholecystokinin, cyclooxygenase, dopamine modulatory networks in pain and part of the basal ganglia circuitry in Parkinson’s disease. Overall, the main concept that is emerging today is that placebos and drugs share common mechanisms of action, which suggests a cognitive/affective interference with drug action. 

This set of modules will consider individual group differences that can occur in the experience of pain. They will illustrate how an individual difference approach can not only help understand the variation in pain that occurs between individuals, but also how such an approach can be used to explore and better understand the psychosocial mechanisms and processes that impact on pain. By better identifying why such variation in pain occurs, it should be possible to design and develop better ways of helping people to manage their pain.

Module Abstracts:

Module 1: Introduction to subgroups. This module will introduce the concept of individual differences and how they relate to pain. It will consider what is meant by subgroups and provide examples of some known individual differences in pain. The focus will be on sociodemographic factors, and how pain assessment methods play a central role in understanding this variation. It will be argued that an exploration of individual differences can generate useful questions about why variation in pain occurs, including the role that psychosocial mechanisms play. Implications are also considered.

Module 2: Focus on sex and gender differences. This module will illustrate the themes developed in module 1 by focusing on the variation in pain that seems to occur between men and women. It will start with definitions of sex and gender, and critically evaluate the evidence for the variation that occurs in the way men and women perceive and experience pain. It will be shown how this evidence to support this view reflects different measurement techniques, from experimental pain inductions methods, through to clinical self-report and treatment-outcomes studies.

Module 3: Gender approaches to pain. This module will show how an individual difference approach to men and women’s pain, can be developed to enable a wider understanding of the psychosocial factors that can impact on pain. Whilst an individual difference approach often focuses initially on between-group differences, it can also be used to consider within-group variation. This will be illustrated by focusing on gender, and how a gender approach to pain can also help us better understand the psychosocial processes that play a role. Examples, such as gender role expectations and beliefs, as well as the role of situational factors are provided.

Module 4: Implications of taking an individual differences approach to pain. The final module will consider the implications of taking an individual group differences approach to pain. It will illustrate this using two examples. The first will show how such an approach can help better understand the biopsychosocial mechanisms of pain. The second example will consider the way such an approach helps to highlight health inequalities. Whilst examples will again focus on sex and gender, it will also note the wider application to other groups and consider interactions with other subgroups. General implications for research and clinical practice will be considered.

• Not effective and/or
• Not tolerated and/or
• Contraindicated
• Not available