Scope, quality and inclusivity of international clinical guidelines on mental health and substance abuse in relation to dual diagnosis, social and community outcomes: a systematic review

It is estimated that up to 75% of patients with severe mental illness (SMI) also have substance use disorder (SUD) and about 60% of adults with SUD have at least one type of SMI [1‐4], with one being either the cause or consequence of the other or various social issues leading to both issues at the same time [5, 6]. Genetic factors for such co-morbidity including variations in how people respond to treatments have also been suggested [7]. Coexisting disorders can result in greater incidence of adverse health outcomes, suicide, unplanned hospital admissions [2, 8‐10] and early mortality [11‐13]. Social consequences include violence, homelessness, involvement with criminal justice system, and relationship breakdowns have also been suggested [14‐17]. For example, between a quarter and a third of prison populations in the Western countries are known to have a dual diagnosis [15, 18]. Involvement with criminal justice system is also known to adversely impact patient access to SMI and SUD services [19].

Assessment and treatment of patients in regard to dual diagnosis presents a challenge for care providers. Care providers can face challenges in managing psychiatric symptoms, substance craving, and social issues as a result of coexisting disorders [20]. In addition, fragmentation of care, for example, physical separation of services can result in barrier to access and provision of care [21‐23]. Different opinion and divergent views of health care providers about treatment plan are also other known challenges [24, 25]. Parallel and separate care provided for each disorder within the same or different healthcare settings for patients with coexisting disorders are likely to be ineffective. This can lead to fragmentation of care, lack of timely access to treatment, withdrawal from treatment, physical multi-morbidity, and early deaths [9, 26, 27]. The advantage of considering both disorders together is that both SMI and SUD are simultaneously addressed and are given due attention [28]. However, practices are often patchy. Despite the known effectiveness of integrated treatment models for patients with coexisting disorders, integrated services availability remains sparse. A study conducted in the United States sampled programs from all over the US and showed that only 18% of addiction treatment and 9% of mental health programs had sufficient capacity to provide simultaneous services for patients with coexisting disorder [29].

A previous systematic review published in 2010 evaluated SMI and SUD guidelines to investigate whether or not they addressed co-occurring disorders [30]. The review considered guidelines published until 2007 and was limited to the inclusion of guidelines published in the National Guideline Clearinghouse database. Guidelines developed by the professional societies and clinical excellence committees are important decision tools that guide health care professionals’ care of their patients. Evidence-based guidelines allow practitioners to follow the best available evidence and also speeds up the adaptation of new treatment approaches. While practitioners may utilize professional judgements and conduct their own evidence search to inform person-centred care, guidelines are cornerstones in healthcare practice and adherence to clinical guidelines is often taken synonymous to evidence based practice [31]. The aim of this systematic review was to explore the scope, quality and inclusivity of international clinical guidelines on mental health and/or substance abuse in relation to diagnosis and treatment of such co-existing disorders and consideration of wider social and contextual issues in treatment recommendations.

This study provides an up-to-date assessment of the scope, quality and inclusivity of international clinical guidelines on mental health and/or substance abuse in relation to diagnosis and treatment of such co-existing disorders and consideration of wider social and contextual issues in treatment recommendations.

The overall quality of the included guidelines rated from a high to moderate quality. The ‘scope and purpose’ and ‘clarity of presentation’ domains were well addressed by the included guidelines. Previous systematic reviews have also demonstrated that clinical guidelines often score high in these domains [58‐60]. For the ‘Stakeholder involvement’, it was noticed that there was a lack of incorporation of patient or public preferences in the guidelines development process. The ‘applicability’ domain was rated low amongst all the guidelines.

This review has demonstrated that there is a lack of clinical guidelines aimed to help healthcare professionals manage the dual diagnosis. More importantly any existing single disorder guidelines should incorporate coexisting disorders in diagnosis and treatment recommendations. These guidelines need to be consistent with current evidence that supported development of integral treatment model, strengthen the connection between mental health care setting and substance abuse services, and providing care for patients’ multiple disadvantages including wider social and contextual factors such as homelessness, involvement with criminal justice system [2, 15, 17].

Treatment guidelines for management of either SUD or SMI have tend to have limited considerations for dual diagnosis. There is a need for the guidelines to be more inclusive in order to enable better diagnosis and treatment and cover social cause and consequences of dual diagnosis such as homelessness. Further emphasis is also needed to promote effective transition of care across services and promotion of self-care after discharge. Professional societies should better communicate the guideline development process as well as rigour in relation to the inclusion and appraisal of evidence base in the guideline development process.