Addiction and Other Mental Disorders

The advancement of a scientific mission relies on accurate communication, and consistent messages, including standard nomenclatures, play a key role in that regard. Language has the power to shape people’s thoughts and beliefs: it can inspire, encourage and unite people towards common and positive goals, but it can also contribute to the emergence of erroneous assumptions and stigmatizing stereotypes.

The words we choose to describe the manifestation of an addictive disorder in association with other mental disorders offer good examples of the potentially harmful aspects of language. Certain terms can have a significant impact on, among others, whether affected individuals will seek help or the quality of treatment they receive.

Here, we propose the term “dual disorder” (DD) as an appropriate description of this clinical entity and provide the reasoning behind our recommendation for its adoption as standard nomenclature. We believe this will facilitate public and professional discourse in the field and help reduce stigma and discrimination around psychiatric illnesses in general and addictive disorders [substance use disorders (SUD) and behavioral addictions] in particular.

Multiple epidemiological studies have established that dual disorders (DD) are an expectation rather than an exception: a substantial fraction of patients who suffer from a mental disorder at some point in their lives will also experience an addictive disorder, and vice versa, which depending on various Demographic factors and specific disorder dyads can range from 40 to 60%.

For the uninitiated, dual disorders are to be expected when it comes to treating people with various mental disorders, a prevalence that increases as the severity of the mental disorders increases. More than 75% of serious psychiatric disorders occur with other mental disorders, such as substance use disorders (SUD) and other addictions.

If we take the perspective of those seeking addiction treatment, although the data is quite variable, about 70% of them will present another mental disorder.

It is very likely that these data reflect an underestimation, to the extent that only diagnostic categories and not symptomatic dimensions were used in the evaluation. This type of information is significantly underrecognized among mental health experts, whether they work within a mental health or addictions care network.

Accumulating evidence suggests that dual disorders reflect etiological overlaps, common contributing factors, and bidirectional relationships between paired conditions. For example, according to the National Epidemiological Survey on Alcohol and Related Conditions (NESARC) study, 96% of patients who suffer from gambling have other mental disorders, with depression being one of the most common.

Importantly, 87% of these patients show high impulsivity, probably a common key marker among those suffering from depression. Therefore, depression could be a specific phenotype that occurs with some measures of impulsivity. Similarly, there is strong evidence to suggest that maladaptive emotion regulation (ER) is critical to the development and maintenance of a wide range of psychopathologies, including SUD.

The mediating role of dysfunctional maladaptive emotion regulation (ER) in the bidirectional relationships between SUD and suicidality offers another good example of the utility of transdiagnostic constructs.

While the lack of existing consensus on appropriate nomenclature hampers both research and clinical efforts, it is only the tip of the iceberg: beneath this cacophony of terms lie many different and often contradictory schools of thought about the nature of this complex and neglected condition. The reality is that DD has been ignored or even denied for years and that, in many settings, the disorder is poorly understood or completely overlooked.

Our field has long been plagued by a lack of clarity about whether TDs represent distinct entities or alternative clinical manifestations of a single underlying pathophysiological process. The reality is that many patients present with a heterogeneous collection of addictive and other mental disorders, and these symptoms and their severity can change over time.

There is broad scientific consensus that all mental disorders, including addiction, are disorders of the brain. This consensus, while not monolithic (some authors opt for a more nuanced approach, although still neurobiological in nature when it comes to SUD), is quite robust and based on multiple lines of evidence.

Yet despite such broad agreement, references to addiction and other psychiatric disorders as separate entities remain common, as if the former were fundamentally different from the latter. If addictions are mental disorders, it is up to us to refer to “addictive and other mental disorders ,” a term in which the order is important because it denotes that an addiction (whether drug-related or behavioral) is also a mental disorder and , therefore, a brain disorder.

Furthermore, it would be difficult to argue that addictive disorders and other mental disorders are two completely different types of mental disorders, since this would require the highly unlikely assumption that the high degree of co-prevalence between them is the result of random factors or measurement artifacts. In fact, the NESARC study has shown, for example, that purely substance-induced mood disorders (SIMD) accounted for a very small percentage of mood disorders among all people with SUD.

Similar patterns of comorbidity and risk factors in individuals with SIMD and those with depressive mood disorder suggest that the two conditions likely share underlying etiological factors.

The emerging consensus is that addiction and other mental disorders are strongly linked, although through complex and not necessarily direct relationships.

Indeed, a variety of factors are likely to contribute to the particularly strong link between a lifetime diagnosis of addiction and other mental disorders, with specific early life events and factors identified as contributing most strongly to the emergence of dual disorders in comparison with the only ones.

Progress in neuroscience is providing new perspectives from which to identify the underlying mechanisms involved in the emergence and development of addictive disorders. In the case of SUD, they have stimulated better pathophysiological theories with the power to improve our understanding of its multilevel interactions with other psychiatric disorders. Similar lines of thinking are also being applied to other addictive disorders, such as gambling or compulsive sexual behavior.

Neuroscience has shown that addictive and other mental disorders often show interconnected and/or overlapping sets of brain processes, rather than being disorders primarily defined by a single behavior (such as excessive, uncontrollable drug use). These connections operate at multiple phenomenological levels, but the clearest examples may be the neurotransmitter systems that show deficits in various psychiatric conditions and that are also the direct targets of addictive drugs.

To state the obvious, all psychoactive substances with a risk of addiction have a counterpart or connection with one or more endogenous systems, such as the dopaminergic, opioidergic, endocannabinoid or cholinergic-nicotinic systems. Therefore, an inherited or acquired impairment in any of these neurotransmitter systems and circuits could help explain common underlying risks for addictive behaviors and other psychiatric symptoms, including pathological personality traits or disorders.

Recent advances in our understanding of such interindividual differences reinforce the need to incorporate the drug of choice model. This model considers that people may be more susceptible to a certain drug or class of drugs (or compulsive video game use, for example), based on individual differences and different mental disorders or symptoms, including endophenotypes, such as traits of personality.

It is well known that the administration of psychoactive substances does not have the same effects between different individuals. One of the clearest examples is that stimulants calm people with Attention Deficit Hyperactivity Disorder (ADHD), but not others, by correcting imbalances in dopamine and norepinephrine levels. This differential effect on different people/brains can be transferred to all psychoactive substances such as nicotine, alcohol, cannabis, cocaine and opioids, as demonstrated by a growing scientific literature.

At the next level of analysis, research in genetics and precision psychiatry has uncovered significant evidence that some DD dyads (e.g., cannabis/attention deficit, tobacco use disorder/schizophrenia, alcoholism/depression, gambling / ADHD, drug use/schizophrenia, smoking/suicide attempts, cocaine/ADHD, appear to show at least some common genetic bases. Such exchange of genetic foundations presents a major challenge to the rigid compartmentalized diagnostic boundaries that separate addictive disorders from others. psychiatric disorders, one with far-reaching implications for translational research and therapeutic outcomes.

Combined analysis at the genetic, neurophysiological and developmental levels is highlighting the bidirectional nature of these relationships. It is clear that chronic use of any psychoactive substance (including addictive substances) can compromise various aspects of brain activity, such as blood flow, neurotransmitter activity, structure and functional connectivity, in ways that could trigger or exacerbate the symptoms of a mental illness. Furthermore, it is not surprising to discover that unmet mental health needs are closely related to psychoactive substance use that can lead to SUD.

When combined, these data points offer new insights into the many ways brain function can be disrupted and help explain the high prevalence of TD. Advances in this area could lead to new approaches that allow healthcare professionals to offer more appropriate personalized assessments and evidence-based treatments for people with TD.

Importantly, it is worth emphasizing that the benefits of adopting a standard term would extend not only to addictive disorders involving psychoactive substances, but also to any behavioral addiction, such as gaming disorder, Internet gaming disorder, or addiction to social networking sites, as they progress through the various stages of the clinical recognition process. It is also likely that behavioral addictive processes, which do not involve psychoactive substances, share multiple neurobiological and genetic links with the consumption of some substances and, by extension, with other psychiatric disorders.

One of the obstacles in the search for a more rational, neuroscience-based classification of TD (as well as other complex mental disorders more broadly) arises from the fact that DSM-based instruments are not suitable for addressing complex phenomena, as they use diagnostic categories (rather than symptom dimensions) that do not always meet the threshold of the diagnostic criteria.

It is evident that, despite the advantages of having a categorical diagnostic system based on the observation of psychopathological phenomena, as Kraepelin did in the beginnings of psychiatry, the lack of sensitivity and reliability makes it difficult to capture the wide spectrum of manifestations of mental symptoms and the relationships between them. This helps explain why the DSM and ICD have systematically and consistently overlooked TD in successive revisions.

This lack of clarity in categorization has provided fertile ground for the proliferation of competing terms that purport to capture the same phenomenon. It is worth noting that each of these terms, including TD, is arbitrary and colored by the “realist” tradition that considers constructs such as schizophrenia or SUD as true reflections of mental phenomena. This, despite the fact that we can only observe the signs, symptoms and course of the diseases that we postulate as a result of these disorders. Therefore, it would be highly desirable to explore next-generation “instrumentalist” approaches that consider existing constructs as mere tools for assessing their empirical adequacy.

It is evident that in this third decade of the 21st century, an era of impressive neuroscientific advances and the dawn of personalized medicine and precision psychiatry, patients and their families have the right to expect more than diagnoses based on the phenomenological description of their experiences. Unfortunately, we are not yet in a position to implement a new classification of mental disorders.

While we wait for the many laudable efforts underway in this direction to bear fruit, WADD proposes adopting TD as the preferred standard terminology, a recommendation that is based not only on the enumerated drawbacks suffered by the competing terms, but also on its own merits.

The term “comorbidity” , coined by Fenstein in 1970 to indicate the coexistence of two different and separate diseases, has been used in psychiatry when two different diagnostic categories coexist, for example, tobacco use disorder and schizophrenia, with the obvious implication that these two symptomatic expressions remained unrelated.

The term “dual diagnosis” operates under a similar logic as it refers to two categorically different diagnoses. This debate dates back many years, when it was proposed that the definition of comorbidity simply specifies an association over time, not necessarily a causal relationship, between conditions.

On the other hand, the term TD offers a broad, symptomatic and dimensional view of the condition that includes different mental disorders or symptoms, including personality traits (endophenotypes), which determine vulnerability or resilience to addictions and other mental disorders. The result is a more coherent heuristic framework for conducting translational research on mental disorders.

Dual disorder is also the term that most naturally conveys the need for broad assessments to identify multiple conditions, as well as appropriately integrated interventions that can modify the trajectory of DD by abandoning the simplistic notion that these are brain disorders that They present different psychopathological expressions.

The term dual disorders , as opposed to dual diagnosis or comorbidity , includes not only a unified view of two diagnostic categories (DSM-5), but also transdiagnostic, syndromic, and symptomatic dimensions , which may be simultaneous or sequential across the lifespan. , and that could easily be incorporated into Research Domain Criteria (RDoC) type projects.

Finally, as suggested throughout this perspective, an equally important benefit of the term is that it could help alleviate the stigma and discrimination that add to the suffering of patients with a dual disorder: The main competing terms imply two different diagnostic entities (hence, separate conditions) that are individually rooted in DSM categorizations and simply occur in one person.

We believe that the proposed harmonization opens the possibility of going beyond the diagnostic categories of the DSM, one of whose problems is not considering dual disorders, and thus include dimensions of mental symptoms and dysfunctional personality traits that could allow a diagnosis and clinical management more accurate.

Clearly, consensus-building efforts are needed to facilitate the adoption of a common term to define the clinical reality of dual disorders.

Here, we call for the adoption of “Dual Disorder” as the standard term in research work and clinical practice. We believe that this would constitute an important step forward not only to improve the education of health professionals, but also to achieve better integration of mental health and addictions services when treating a single person suffering from different manifestations of mental disorders. .

Furthermore, this new perspective must reach patients, their families and society in general, who suffer from disorders that have been stigmatized, misunderstood, discriminated against and mistreated for too long, and allow them to find “ the right door” that will lead them. to effective recovery.