An update on cannabis use disorder with comment on the impact of policy related to therapeutic and recreational cannabis use
Alan J. Budney,· Michael J. Sofis,· Jacob T. Borodovsky
European Archives of Psychiatry and Clinical Neuroscience, 2019
© Springer-Verlag GmbH Germany, part of Springer Nature 2019
Confusion and controversy related to the potential for cannabis use to cause harm, or alternatively to provide benefit, continues globally. This issue has grown in intensity and importance with the increased recognition of the public health implications related to the escalation of the legalization of cannabis and cannabinoid products. This selective overview and commentary attempt to succinctly convey what is known about one potential consequence of cannabis use, the development of cannabis use disorder (CUD). Such knowledge may help guide a reasonable and objective public health perspective on the potential impact of cannabis use and CUD. Current scientific data and clinical observation strongly support the contention that cannabis use, like the use of other substances such as alcohol, opioids, stimulants, and tobacco, can develop into a use disorder (addiction) with important clinical consequences. Epidemiological data indicate that the majority of those who use cannabis do not have problems related to their use, but a substantial subset (10–30%) do report experiencing symptoms and consequences consistent with a CUD. Treatment seeking for CUD comprises a substantial proportion of all substance use treatment admissions, yet treatment response rates show much room for improvement. Changing cannabis policies related to its therapeutic and recreational use are likely to impact the development of CUD and its course; however, definitive data on such effects are not yet available. Clearly, the development of more effective prevention and treatment strategies is needed for those vulnerable to developing a CUD and for those with a CUD.
Keywords : Cannabis · Cannabis use disorder · Marijuana · Policy · Prevalence · Treatment · Legalization
Introduction : does cannabis addiction exist
and how do you define it ?
Confusion, debate, and controversy related to the potential for cannabis use to cause harm, or alternatively to provide therapeutic benefit continues globally. Over the last decade, these issues have grown in intensity and importance with increased recognition of the substantial public health implications related to the escalation of (a) the decriminalization and legalization of cannabis and cannabinoid products, (b) the perception that cannabis has therapeutic potential for a numerous and diverse set of disorders, and (c) a burgeoning and lucrative cannabis industry. The seeming contradiction that a substance can cause harm and have therapeutic value is not unique to cannabis. Most substances (i.e., opioids, cocaine, stimulants, hallucinogens, tobacco, and even distilled alcohol) that have addictive potential, have also been deemed to have therapeutic potential and some have been used legitimately by medical providers. The current and pressing challenge with cannabis is to develop well-reasoned policies that consider factual information about risks and potential benefits of cannabis and cannabinoid compounds in service of mitigating potential harm and maximizing potential benefits.
This brief manuscript attempts to help address this challenge by conveying what is known about one potential harmful consequence of cannabis use, the development of cannabis use disorder (CUD), or what some refer to as cannabis addiction [1–3]. Although many people do not believe that cannabis has addictive potential, a large volume of scientific and clinical data demonstrate that a proportion of those who use cannabis do indeed develop an addiction that is much like that of other substance addictions . Here, we provide a selective overview of the literature on CUD with associated commentary that highlights and discusses some key issues that contribute to misperceptions related to cannabis, and its potential consequences. To that end, we drew from (a) literature reviews and scientific articles on relevant topic areas identified in Pubmed using diverse search strategies, (b) articles cited in these reviews and articles, (c) the DSM-5 and its source materials, (d) databases and published reports from large epidemiological studies, and (e) select book chapters from recent texts on cannabis identified via google searches. Thus, this manuscript is not a systematic review of the scientific literature, rather, it is a selective overview and synthesis drawing from the large multidisciplinary literature relevant to the development and course of CUD. We end by providing some perspective on a pressing concern, that is, how might changes to the legal and regulatory status of cannabis impact the development of CUD and its consequences.
Because of the plethora of mixed messages about cannabis communicated to the public, policymakers, and healthcare workers, we believe it is important to clearly define some key terms prior to discussing the CUD literature. First, when we use the word “cannabis”, we are referring to either the cannabis plant material or extracts from the cannabis plant that contain substantial amounts of tetrahydrocannabinol (THC). THC is the compound in the cannabis plant that produces the commonly desired euphoric-like effects (the “high”) [2, 5]. THC interacts with the CB1 receptor in the brain to stimulate the typical “high” sought by most cannabis users. This high produces the desire for repeated use, which for some cannabis users develops into a CUD . “Cannabis” in this article will not be referring to cannabidiol (CBD) products that contain no or very small amounts of THC. CBD is a compound in the cannabis plant that has recently generated a great deal of interest related to its potential therapeutic effects, and which does not produce euphoria when ingested . Note that this working definition of “cannabis” as a substance that contains a substantive amount of THC is not the scientific definition of cannabis. It is used here because, when discussing the addictive potential of cannabis, it is crucial to distinguish between cannabis products with THC versus those with primarily CBD.
Second, it is important to clarify what is meant by CUD. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5)  and the International Statistical Classification of Diseases and Related Health Problems (ICD-10 or 11) have clear operational definitions of a syndrome that can develop from excessive use of cannabis (and any other substance) . The DSM-5 criteria for a diagnosis of CUD, which are generic for all substance use disorders, specify 11 signs and symptoms that relate to impaired control over one’s consumption, social impairment, risky use, and physical dependence, i.e., tolerance or withdrawal. Severity of CUD can range from mild (meeting 2–3 criteria), to moderate (4–6 criteria), to severe (7 or more criteria). The ICD operationalizes CUD somewhat differently from the DSM-5. ICD-10 has two separate CUD disorders: harmful use and a dependence syndrome (i.e., similar to the abuse and dependence diagnoses of the previous version of the DSM). The diagnosis of harmful use is defined as a pattern of psychoactive substance use that is causing damage to health, which may be physical or mental. The dependence syndrome is defined as a cluster of physiological, behavioral, and cognitive phenomena in which the use of a substance takes on a much higher priority for a given individual than other behaviors that once had greater value. A dependence syndrome is diagnosed if a person meets three of six specified criteria.
The specification and inclusion of CUD in both DSM and ICD, which both use generic criteria across all addictive substance use disorders, communicate a few important realities about cannabis and its potential for “addiction”. First, health and medical experts and scientists consider CUD to be a valid and clinically important type of mental disorder that occurs in the general population, is not rare, and is experienced in much the same way as other SUDs [3, 8]. An overwhelming body of evidence for this assertion has accumulated and has been reviewed in detail elsewhere [9, 10]. The supporting data include research from nonhuman and human behavioral pharmacology, neuroscience and neuroimaging, genetics, clinical assessment and treatment, health service surveillance, and clinical epidemiology. Second, and particularly noteworthy, a valid cannabis withdrawal syndrome has been characterized such that a diagnosis of cannabis withdrawal disorder is included in the DSM-5 and experiencing withdrawal is one of the CUD diagnostic criteria.
In summary, CUD clearly develops and manifests in much the same way as other SUDs. The majority of those who have used cannabis do not develop a CUD, but among those that do, some develop a mild, some a moderate, and some a severe syndrome . Below we review and discuss scientific information that we believe can assist readers to develop a reasonable public health perspective on CUD (see Table 1 for an overview of the primary issues probed in this review).