Editorial

Citation

Szerman, N. and Martinez-Raga, J. (2015), "Editorial", Advances in Dual Diagnosis, Vol. 8 No. 2. https://doi.org/10.1108/ADD-03-2015-0004

Editorial

Article Type: Editorial From: Advances in Dual Diagnosis, Volume 8, Issue 2.

Nestor Szerman and Jose Martinez-Raga

Dual disorders: two different mental disorders?

Dual disorders/dual pathology/co-occurring disorders: these are the terms commonly accepted within the mental health field to refer to those patients who suffer from an addictive disorder and other mental disorders. Dual disorders (DDs) can occur simultaneously or, even more importantly, sequentially throughout their life span.

"Sequential DDs" is a very important concept because many previous studies on the prevalence and co-morbidity of substance use disorders (SUDs) and other mental disorders in various clinical populations have failed to take into account prevalence of lifetime substance use disorders (Lev-Ran et al., 2013).

Over recent decades, clinicians, researchers, economists, and policymakers have given increased attention to the challenges of identifying co-occurring disorders/dual pathology (Szerman et al. 2014; Roncero et al. 2014).

A number of different terms have been applied to refer to the vast population of patients with, addictive disorders and other mental illnesses, including dual diagnosis, dual disorders, mentally ill chemical abusers, chemically addicted mentally ill, co-occurring disorders, dual pathology or comorbid disorders (Banerjee et al., 2002; Szerman et al., 2013).

This term DDs is arbitrary (literally means nothing) and originates from historical reasons, with the aim of allowing all mental health professionals to identify that we are talking about addiction and other mental disorders.

In the mental health field there is an additional difficulty: there are many different and conflicting schools of thought about the nature of this condition. The reality is that DDs have been ignored or denied for years, and in many settings it is still overlooked.

Four major epidemiological surveys in the general population have examined the co-occurrence of SUDs and other psychiatric disorders in the USA: the Epidemiological Catchment Area (ECA) Study (Regier et al., 1990), the National Comorbidity Survey (NCS) (Kessler et al., 1997), the National Comorbidity Survey Replication (NCS-R) (Kessler et al., 2005), and the National Epidemiological Survey on Alcohol and Related Conditions (NESARC) (Grant et al., 2009). All these epidemiological studies coincide in showing that DDs are the common finding, not an exception. Furthermore, epidemiological research also indicates a reciprocal contribution to the development of the other disorder in dual disorders (Compton et al., 2005; Kessler, 2004; Volkow, 2007). Under reporting of substance use is common in patients with severe mental illness (Bahorik et al., 2014) and in the majority of cases tobacco is excluded. In addition, there is a strong association between a lifetime diagnosis of any mental illness and rates of transition from substance use to substance use disorder (Lev-Ran et al., 2013; Martinez-Raga et al., 2013). It should also be considered that comorbidity may not be optimally addressed when using diagnostic categories rather than symptom dimensions (that may not reach the diagnostic threshold).

The vast majority of individuals exposed to substances with addictive properties do not progress to develop an addictive disorder. It is possible that a common genetic vulnerability might increase the risk of both SUDs and any other mental disorder. Longitudinal research supports the conclusions that many mental disorders have their onset prior to the emergence of the SUDs (Grant et al., 2009; Compton et al., 2013).

The population with addictive disorders and other mental disorders is heterogeneous, and the prevalence of DDs differs according to diagnostic groups. One of the overarching issues in relation to DDs is the nature of the relationship between addictive disorders and other psychiatric disorders. The rapid development of technical advances in neuroscience has led to a better understanding of the molecular biology, neurotransmitter systems and neural circuitry involved in substance use disorders and other mental disorders.

In each DSM categorical diagnosis we can unravel different phenotypes. By dichotomizing the phenotypes, using categorical diagnosis rather than symptom dimensions, the analysis is less accurate. This is the reason why we discard naming these disorders "comorbidity disorders" (the relationship between two different categorical diagnoses).

Are we talking about two disorders? Are addiction disorders and other mental disorders two different mental disorders?

This symptomatic high concurrency that cannot be explained by conceptual or measurement artefacts strongly suggests that the co-occurrence of DDs is not due solely to random or coincidental factors. It seems reasonable to explore the assertion that both conditions are in some ways causally linked.

Various factors may contribute to the particularly strong association between a lifetime diagnosis of an addictive disorder and other mental disorders. According to different theories, this phenomenon is not purely coincidental, since both pathologies share common brain substrates and factors (Volkow, 2001).

Progress in neurobiology has provided a new form of identifying the neurobiological mechanism involved in the development of problematic drug use and/or addiction disorder. Over the past few decades, different biological addiction theories have been proposed by researchers and clinicians (Badiani et al., 2011).

All psychoactive substances with abuse potential have a counterpart or connectivity with some endogenous system such as the opioid system, the endocannabinoid system, the cholinergic-nicotinic system, etc. An inherited or acquired deficiency in these neurobiological systems and circuits may explain addictive behavior and occurrence of other psychiatric symptoms, including personality pathological traits or disorders (Szerman et al., 2013).

Has our field, to date, essentially excluded biological discoveries that are involved in SUDs and other mental illnesses?

How can one decide whether "co-occurring disorders" are truly separate entities or simply alternative clinical manifestations of a single core, underlying a pathophysiological process?

What is the reason that we can prescribe substances with addictive properties with focus on therapeutic treatment? We know the therapeutic psychiatric properties of stimulants, opioid agonists, and nicotine and some cannabis derivatives. Probably moral barriers are one of the major impediments to deepen this therapeutic approach.

The inclusion in the latest version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) of gambling disorder within the addictive disorders must change our way of understanding and dealing with addictions. From a neurobiological perspective, we should not maintain an explanatory model that provides only results in neuroadaptation to the continued use of substances of abuse.

We are moving away from the classic addiction paradigm based on drug-induced neuroplasticity and on acquired vulnerability, largely dominant in laboratory settings (Swendsen and Le Moal, 2011) toward the new paradigm "individual-centered" approach that places individual variation as the focus of interest: the strong association of addiction and dual pathology, such as certain personality traits (Volkow et al., 2001) or other mental disorders.

Why were DDs (co-occurring-independent disorders) specifically overlooked in the DSM-V? Why does the DSM-V give such salience or relevance to substance-induced disorders? The NESARC study has demonstrated that, for instance, purely substance-induced mood disorders (SIDD) account for a very small percentage of mood disorders among all those with SUDs (Grant et al., 2004). Similar patterns of comorbidity and risk factors in individuals with SIDD and those with mood depressive disorder suggest that the two conditions may share underlying etiological factors (Blanco et al., 2012).

DDs or pathology, probably can be best understood as a neurodevelopmental disorder (Szerman et al., 2013), considering that these are disorders that begin during the individual development and may present with different phenotypes, such as addiction-related or other psychiatric symptoms, at different stages of the life span.

This new understanding of how brain functions are disturbed at the circuit level is providing a new insight into why dual disorders are so highly prevalent.

Perhaps the most important aspect about DDs is its essence to provide a broad framework for conducting clinical approaches and research on mental disorders from a wholly new perspective.

Their findings also support the hope that appropriate integrated interventions could modify the disease course of DDs knowing that it is just one brain disorder with different psychopathological expressions.

A new approach is needed to enable clinicians and managers to offer adequate assessment and evidence-based treatments to patients with dual disorders/pathology.

References

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Papers in this issue

In "Identifying and responding to alcohol misuse in memory clinics: current practice, barriers and facilitators," Thake et al. examine current practice, barriers and facilitators to identifying and addressing alcohol problems in patients attending memory clinics in England and Wales. The results stress the need for staff training and specific guidance for memory clinics on how to identify and respond to alcohol problems. In the second manuscript, "A delicate balance: intervention with mothers with dual diagnosis and their infants" Tsantefski et al. present a longitudinal case study of 22 substance-dependent women attending a specialist obstetrics service in Australia. The findings demonstrate that while women are referred to many services by the specialist service, many chose not to attend. Child protection involvement and infant removal were common. The authors describe promising interventions in the field that could improve the care and outcomes for substance-dependent mothers and their infants. In "A new horizon?": evaluation of an integrated Substance Use Treatment Programme (SUTP) for mentally disordered offenders," Miles et al. present findings from a three-year follow up of mentally disordered offenders (MDOs) with a history of substance misuse. At three years, most MDOs were living in the community and the majority remained abstinent from substance use. In the final paper, Guest et al. present the "Delivery of a mainstreaming treatment model towards co-existing difficulties: a brief exploration of practitioners understanding, views and reported experiences." The model, delivered in a mental health NHS service addresses co-existing moderate and severe mental disorders and drug and alcohol problems.