The primary motivation for the use of medicines is to rectify physiological or psychological perturbations, although the non-therapeutic abuse of medicinal compounds can occur and hence the requirement for abuse liability testing. In contrast, tobacco is commonly viewed a priori as an unsafe substance at any dose, with use reportedly motivated by a desire to mitigate the negative effects of nicotine withdrawal. Abuse liability testing of new tobacco products commonly seeks to examine if the nicotine addictiveness noted for traditional tobacco products is increased by novel product characteristics which could draw in new-users or prevent existing users from quitting.

Curiously, the motivation to use consumer products containing popular or cultural compounds with psychological and physiological effects (e.g., chocolate, caffeine, CBD) is less well understood, not least because there are no clear pathological drivers for such behavior. However, one strong hypothesis is that the appeal of a consumer product and the satisfaction derived from its use provide sufficient dimensional space in which to describe and understand consumer choices. That is because these dimensions reflect the well characterized operation of normal, everyday motivated behavior (McDougall 1922; Rolls 2016). This conceptual focus places products containing popular or cultural compounds into the same theoretical space occupied by other everyday consumer goods – from magazines to cars, from pastries to vacations.

Quality of Life

Product appeal influences appetitive behavior (e.g., searching for a particular food) through incentives such as sight, smell, anticipation – and memory after (at least) the first experience of product use. Meanwhile, product satisfaction reinforces consummatory behavior (e.g., eating the food) through properties such as satiation or intoxication. For the individual, everyday internal signals (e.g., hunger; boredom; “fear of missing out” FOMO) are perceived as aspects of “wanting” and drive appetitive behavior, mainly through the dopaminergic system. Subsequently, the internal signals which follow consummatory behavior (e.g., pleasure, relief), are perceived as aspects of “liking” and mediated mainly by the endogenous opioid system (Berridge 2009). Most importantly, no additional pathological drivers (i.e., illness or addiction) are required to explain such motivated behavior.

In a seminal paper, Müller and Schumann (2011) further delineated the appeal and satisfaction derived from the non-addictive use of products with psychoactive effects under eight categories

1. Improved social interaction
2. Facilitated sexual behavior
3. Improved cognitive performance and countering fatigue
4. Facilitated recovery from and coping with psychological stress
5. Self-medication for mental problems
6. Sensory curiosity – expanded perception horizon
7. Euphoria, hedonia, and “high”
8. Improved physical appearance and attractiveness.

While the breadth of these categories captures the universe of motivations, not all psychoactive compounds exhibit activity in every category, but these categories are all linked in that they appear to contribute to improved quality of life to the user.

Behavioral Toxicity

Of course, it is possible that there may also be negative effects from the use of everyday consumer products with psychological or physiological effects on other important activities of daily life (e.g., memory, reaction time). This has been defined as behavioral toxicity (Ramaekers 1998). Moreover, if the use of these products becomes uncontrolled then harm may result to the user and to others. Such a pathological process underlies, and is the short definition of, abuse liability and subsequent addiction.

There is a growing recognition that behavioral toxicity can be troublesome to both the individual and society, so attempts to quantify such effects have increased. For example, while a comprehensive examination of the effects of medicines on these domains have not generally been required for safety registration, the U.S. FDA has now issued explicit guidance on the need to evaluate vehicle driving impairment if evidence of behavioral toxicity accumulates in earlier phases of drug development (U.S. FDA 2017a). Similarly, environmental protection agencies have previously shown interest in using measures of behavioral toxicity to examine possible neurotoxic effects of environmental pollutants (U.S. National Committee for the International Union of Psychological Science 1990).

The Measurement Landscape

The activities of daily life cover a multitude of divergent behaviors but may be conveniently captured under the following domains with examples of related, measurable processes in parentheses:

• Biological parameters (e.g., brain imaging, receptor function, self-administration, tolerance) which examine changes to brain structure and function.
• Cognitive parameters (e.g., alertness, concentration, memory) examining skill execution.
• Developmental parameters (e.g., learning, task acquisition, gateway effects) examining ability to acquire and act upon information.
• Social and personality parameters (e.g., social interaction, emotional lability) which examine the resilience of internal interactions with self and external interactions with others.
• Mental and physical health parameters (e.g., stress resilience, sleep quality, dependence) which examine perturbations to normal function which may lie on the path to illness.

Often these parameters operate in combination during higher-level activities such as car driving, skilled working, social engagements, and hobbies.

Conclusion

In the absence of an associated technical / legal product standard such as “Safe and Effective” (pharmaceuticals) or “Appropriate for the Protection of the Public Health” (tobacco), consumer product manufacturers may wish to consider what high-level acceptance criteria can be employed to effectively characterize their consumer products and quantify any potential negative impacts on health over basic toxicological screening.

As the number of consumer products containing popular or cultural compounds with psychological and physiological effects increases, the assessment of quality of life and behavioral toxicity may be an appropriate rubric under which to understand the positive and negative impacts of product use and to satisfy potential future regulatory requirements.

McKinney RSA can assist you in developing programs to establish the fundamental motivations behind the use of your consumer product and delineate any evidence of toxicity. Such data can both contribute to a dossier supporting product claims and help meet emerging regulatory requirements. Please contact us via form or by emailing info@mckinneyrsa.com

About Contributing Author Neil Sherwood

Dr. Sherwood earned a Doctorate in Human Psychopharmacology from Leeds University, UK and is currently the Principal, at Neil Sherwood Consulting. Dr. Sherwood continuously monitors issues regarding the relationship between product use and consumer health. He provides scientific and regulatory overviews through reports, briefings, workshops and presentations. Additionally, he develops appropriate public responses through scientific communication and advocacy. He also advises on scientific and technical solutions where uncertainty remains.

Dr. Sherwood was the Team Leader, Smoking and Health, Scientific and Regulatory Affairs, at JT International SA, Geneva, Switzerland. His duties included leading activities of a team of Doctoral and Master level scientists to establish global scientific priorities in response to current and future product challenges. He was accountable for leading the incorporation of clinical and public health science into the JT Group and leading the development of scientific data acquisition plans to meet emerging regulatory requirements (e.g., FDA PMTA, MRTPA).

References:

• Berridge K (2009) Wanting and Liking: Observations from the Neuroscience and Psychology Laboratory. Inquiry 52: 378-398.
• McDougall W (1922) An Introduction to Social Psychology. Michigan: Methuen and Co.
• Müller CP and Schumann G (2011) Drugs as instruments: A new framework for non-addictive psychoactive drug use. Behavioral and Brain Sciences 34, 293-347.
• Ramaekers JG (1998) Behavioural Toxicity of Medicinal Drugs. Drug Safety, 18, 189-208.
• Rolls ET (2016) Motivation explained: Ultimate and Proximate Accounts of Hunger and Appetite. Advances in Motivation Science 3: 187-249.
• U.S. Food and Drug Administration (2017a) Evaluating Drug Effects on the Ability to Operate a Motor Vehicle. Guidance for Industry. Silver Spring, MD: U.S. Department of Health and Human Services.
• U.S. National Committee for the International Union of Psychological Science (1990) Behavioral Measures of Neurotoxicity. Washington DC: The National Academies Press.