Policy context

The National Service Framework (NSF) for Mental Health (Department of Health, 1999), while emphasising the importance of tackling dual diagnosis, failed to include standards and service models to address the challenges posed by patients with dual diagnosis, including those with severe mental illness. It was in the context of this gap in policy that the Dual Diagnosis Good Practice Guide (Department of Health, 2002a ) was launched. The NSF also omitted to provide standards and service models for people with substance use disorders, an omission that was addressed by the complementary guidance on models of care launched by the National Treatment Agency for Substance Misuse (2002).

The key message in the Dual Diagnosis Good Practice Guide is that substance misuse is usual rather than exceptional among people with severe mental health problems, and that the relationship between the two disorders is complex. Individuals with dual diagnosis have varied and complex needs and require high-quality, comprehensive and integrated care that should be delivered within the mainstream mental health services. The guide recognises that mainstreaming will not reduce the role of drug and alcohol services, which will continue to treat the majority of people with substance misuse problems and to advise on substance misuse issues. The guide summarises good practice in relation to treatment and sets out a programme for local implementation of the appropriate service model. It is concluded that integrated care by a single team delivers better outcomes than serial care (sequential referrals to different services) or parallel care (more than one service engaging with a patient at the same time). The guide recommends that more UK-based research is required to establish the evidence base, and that well-organised parallel care can be used as a stepping stone to integrated treatment delivered by existing mental health services following training and support from substance misuse services.

It should be noted that the Dual Diagnosis Good Practice Guide was launched at the same time and place as two other guidelines: Adult Acute Inpatient Care Provision Guidance (Department of Health, 2002b ) and National Minimum Standards for Psychiatric Intensive Care Units and Low Secure Environments (Department of Health, 2002c ). Neither of these other publications emphasises the importance of dual diagnosis. The intensive care guidance specifies substance misuse as an exclusion criterion on two counts, and falls into the trap of emphasising the primacy of one diagnosis over another in the acute situation, potentially perpetuating the passing of complex patients from ‘pillar to post’ – the title of a video produced by the mental health charity Mind in Croydon (2004) – because of the recognised diagnostic uncertainty and tautology. It is simplistic to adopt a dualistic approach to behaviour where the relationship between the two conditions is properly comorbid, with shared aetiological factors.

Defining dual diagnosis

Currently recognised subgroups of patients with dual diagnosis are defined by presumed aetiological mechanisms: primary psychiatric disorder with secondary substance misuse, substance misuse with secondary psychiatric disorder, and psychiatric symptoms related to substance intoxication or withdrawal. These categories are consistent with the operationally defined corresponding categories in DSM–IV (American Psychiatric Association, 1994), in which a distinction is made between independent (primary psychiatric comorbidity) and substance-induced (organic) psychiatric comorbidity and the category of expected symptoms of substance use or withdrawal. The evidence base for these aetiological subgroups has identified two key aetiological factors for dual diagnosis: the presence of underlying antisocial personality disorder and the vulnerability of people with severe mental illness to non-dependent problematic substance misuse (the supersensitivity model; Reference Mueser, Bellack and BlanchardMueser et al, 1998). The self-medication hypothesis has not been sustained despite its plausibility and popularity with users and clinicians alike. In the case of schizophrenia, it has been suggested that the emergence of comorbid substance misuse is integral to the disorder and is related to the disconnection in the neural networks that occurs in the schizophrenia disease process (Reference Chambers, Krystal and SelfChambers et al, 2001). An important piece of the jigsaw that is often missing is the underlying personality disorder, offering a triple diagnosis. This absence is related to the difficulties of reliably diagnosing personality disorder in the context of comorbidity. An inclusive and pragmatic approach would offer the typology of:

1. • severe psychiatric disorder with problematic substance misuse, with or without an underlying personality disorder;

2. • substance-induced psychiatric disorder;

3. • substance dependence with personality disorder, without comorbid psychiatric disorder.

Assessment

As comorbidity is the rule rather than the exception, it is crucial that all patients are routinely screened to detect substance misuse in those presenting to general psychiatric services and to detect psychiatric problems in those presenting to addiction services. Detection is based on self-report, informant report and laboratory tests. Hair analysis carries a major advantage over urine testing in that it covers much longer periods than a single urine test (Reference McPhillips, Kelly and BarnesMcPhillips et al, 1997). Those with comorbidity are then provided with a specialised assessment (Reference Noordsy, McQuade, Mueser, Graham, Copello and BirchwoodNoordsy et al, 2003), which should include the items listed in Box 1.

Diagnostic assessment of comorbidity optimally takes place following detoxification, to disentangle substance-induced disorders from primary comorbid psychiatric disorders and expected effects of substance intoxication/withdrawal using DSM–IV criteria (see above). Psychiatric symptoms or disorder that persist after 4 weeks of substance withdrawal indicate primary comorbidity. Similar considerations apply for the optimal assessment of personality disorders (Axis I), particularly in the setting of Axis II comorbidity.

Treatment models

People with comorbidity often fall into the cracks between general psychiatric and specialist addiction services. Whereas the culture of addiction services is dedication to ‘clients’ who want to be helped, general psychiatric services are obliged to treat all patients, including reluctant ones detained under the Mental Health Act. The plight of these patients is compounded by the lack of community care facilities, including residential care, while day centres and rehabilitation facilities often do not admit them. Several models for treatment of comorbidity have evolved.

The serial treatment model involves management of the psychiatric disorder and substance misuse in separate settings and services; for example, patients are treated first in the general psychiatric service, and when recovered are referred to the specialist addiction service.

The parallel treatment model involves the concurrent treatment of substance misuse and psychiatric disorder by different staff and in different settings. Both serial and parallel treatment models have serious limitations for optimal treatments of both disorders, with high rates of patient withdrawal.

The preferred model is integrated treatment, in which the same staff treat both disorders in the same setting. The limitation of this model, however, is that it may not provide the same intensity of treatment for the substance misuse as is afforded to the psychiatric disorder. A review by Reference Drake, McHugo and ClarkDrake et al(1998) of 36 studies of the effectiveness of integrated treatment for dual diagnosis patients identified ten studies (six uncontrolled and four controlled) of comprehensive, integrated out-patient treatment programmes which were effective in engaging patients in services, reducing substance use and sustaining remission. Outcomes related to hospital use, psychiatric symptoms and other domains were less consistent. Several features of the programmes appeared to be associated with effectiveness: assertive outreach, case management, and a longitudinal, stage-wise, motivational approach to treatment of the substance misuse.

The integrated approach involves individually tailored treatments and differs from traditional substance misuse treatment in several respects:

1. • the focus is on preventing anxiety, rather than breaking through denial;

2. • it emphasises trust, understanding and learning, rather than confrontation and criticism;

3. • it emphases reducing harm from substance use, rather than abstinence;

4. • it uses slow-paced and long-term management, rather than rapid withdrawal and short-term treatment;

5. • it provides staged and motivational counselling, rather than confrontation;

6. • it employs supportive clinicians readily available in familiar settings, rather than only during working hours and at clinics;

7. • 12-step (Alcoholics Anonymous) groups are available for those who choose and can benefit from them, rather than being required for all patients.

Reference Drake, Bartels and TeagueDrake et al(1993), using an evidence-based approach, identified nine principles for the treatment of substance misuse in severely mentally ill patients (Box 2).

A Cochrane systematic review (Reference Ley, Jeffrey and McLarenLey et al, 1999) of treatment programmes for those with both severe mental illness and substance misuse identified six relevant studies. It found no clear evidence supporting an advantage over standard care of any type of programme, including integrated assertive community treatment and a residential treatment programme.

Treatment considerations

The treatment of comorbidity is fraught with difficulties which are related to diagnostic assumptions and to the setting in which the comorbidity is encountered. One consideration is a tendency for the comorbid condition to be considered as being of secondary importance and hence to be ignored or insufficiently treated. This is based on the assumption that the comorbid disorder is secondary to the primary disorder – be it substance misuse or other psychiatric disorder – and that treatment of the primary disorder may resolve the secondary disorder, which is not considered to require specific treatment. Also, there is general reluctance to treat psychiatric patients who misuse substances. Reasons for this are multiple, and include concern about possible toxic interaction between the prescribed medication and the substances that are misused; the assumption that active substance misuse will cause worsening of comorbid psychiatric symptoms and impair response to treatment; and the fear that ‘enabling’ the patient by treating the psychiatric illness would diminish the patient's motivation to deal with the substance misuse problem (Reference Weiss, Najavits, Kranzler and RounsavilleWeiss & Najavits, 1998).

Although assessment of comorbidity is best done after the substance of misuse has been withdrawn, complete withdrawal is rarely obtained in an out-patient setting and treatment of the psychiatric disorder often begins while the patient is still misusing the substance. There is evidence that treatment of the psychiatric disorder during active substance misuse is effective and occasionally also has a positive impact on the substance misuse itself. Reference Saxon and CalsynSaxon & Calsyn (1995) showed that outcome at the end of 1 year of treatment in a substance misuse programme was as favourable for dually diagnosed patients as for those with substance misuse alone. Controlled trials of antidepressants in patients with depression who misuse alcohol have demonstrated efficacy in treatment of the depressive disorder and modest effect on the substance misuse. These findings counter the assumption that treatment of the comorbid psychiatric disorder in those actively engaged in substance misuse represents a form of ‘enabling’ (Reference Cornelius, Salloum and CorneliusCornelius et al, 1997).

Specific treatment approaches

Treatment is guided by a comprehensive assessment, and in integrated settings it involves a number of interventions matching patients’ needs. Treatment is normally provided in the community with assertive outreach, but is also given in in-patient settings, particularly when the patient needs to be stabilised, to be assessed following detoxification and to achieve abstinence. Importantly, staff should hold a realistic and longitudinal view of treatment of substance misuse, with different interventions matched to different stages of the treatment process:

1. • Engagement – regular contact and development of a therapeutic alliance, and meeting basic needs.

2. • Persuasion – motivational techniques to enhance motivation to change (reduce substance use).

3. • Active treatment – from harm reduction to abstinence-oriented approaches.

4. • Relapse prevention – identification of high-risk situations for relapse and management of future relapses.

Reference Noordsy, McQuade, Mueser, Graham, Copello and BirchwoodNoordsy et al(2003) have mapped various interventions at different stages of treatment (Table 1).

Table 1 Potential interventions at different stages of treatment

		Stage of treatment
	Engagement	Persuasion	Active treatment	Relapse prevention
Case management	×	×	×	×
Family work	×	×	×	×
Pharmacological treatment	×	×	×	×
Assertive outreach	×	×	×
Coerced or involuntary interventions	×	×	×
Residential programmes		×	×
Motivational interviewing		×	×
Persuasion groups		×	×
Cognitive–behavioural counselling		×	×	×
Social skills training		×	×	×
Vocational rehabilitation		×	×	×
Active treatment groups			×	×
Self-help groups			×	×

Reference Drake and MueserDrake & Mueser (2000) identified the following common components of integrated treatment.

1. • Case management – multidisciplinary case management with assertive outreach to engage and retain patients in community services.

2. • Close monitoring – medication supervision, urine drug screening and coercive approaches.

3. • Substance misuse treatment – motivational approaches; harm reduction and cognitive–behavioural therapy in individual, group and family settings; self-help (12-step programmes) and social skills training.

4. • Rehabilitation – provision of long-term support in the community, whether day care or residential care, to enable restoration of social and occupational function (supported education and employment).

5. • Housing – both supported and independent.

6. • Pharmacotherapy – provision of antipsychotic medication (particularly clozapine) in those with schizophrenia, and improvement of compliance by providing education and medication supervision.

Optimal services

The optimal model of care for patients with comorbidity could be developed in the context of current service models and structures, provided minimum standards for quality are established (Reference Abou-SalehAbou-Saleh, 2000) (Box 3).

Reference JohnsonJohnson (1997) advocated the development of a dedicated, highly specialised service for patients with dual diagnosis along the lines of the integrated treatment model discussed above. She suggested integrated models of addiction workers working within community mental health teams (CMHTs); training and supervision of CMHT staff in substance misuse; and establishing dual diagnosis specialists in CMHTs. However, there is a risk that such a service could become too selective and exclusive, with two dangers: exclusion of the most difficult patients, and de-skilling of the staff working in addiction and general psychiatric services.

The national guidance on good practice in dual diagnosis (Department of Health, 2002a ) is timely and welcome, and in so far as it focuses on the needs of patients with serious mental illness and comorbid substance misuse, it is a step in the right direction. It places lead responsibility with mainstream mental health services; provides ‘joined-up thinking’ at the policy level, standards of good practice in assessment and treatment, with good examples such as the Kingston Community Drug and Alcohol Team, the Haringey Dual Diagnosis Service and the COMPASS programme in Birmingham; and gives guidance on implementation and commissioning standards. However, the document fails to address important issues relating to social care, the resource implications of this major service development, and the interface between mainstream mental health services and addiction services, as well as implications for the future and the scope of addiction services.

Concerning social care, particularly the housing needs of this vulnerable population, there is a lack of provision, with limited access to mainstream community care and residential care in mental health and addiction. It is a prime task for local implementation teams working with drug action teams to tackle this problem. The provision of housing is also important because the pooled budget for drug misuse is targeted towards meeting the rising demand for drug misuse services, and it is doubtful whether mainstream mental health funding could cater for the needs of this population.

A most important implication of the guidance on dual diagnosis is the role of addiction services vis-à-vis mainstream mental health services, which at present lack capacity to deal with this population. A survey of the training and support needs of staff working with patients with dual diagnosis showed that mental health service workers lacked the knowledge and skills for assessment and treatment of substance misuse and were insufficiently aware of the available resources and how to access substance misuse services (Reference Maslin, Graham and CawleyMaslin et al, 2001). The role of addiction services is paramount in providing training and support for development of capacity and, importantly, in sustaining this capacity with optimal supervision and the agreement of local shared care working arrangements and care pathways, including the care programme approach. Our experience at South West London and St George's Mental Health NHS Trust has been positive, with the introduction of shared-care working arrangements and protocols to ensure that patients with dual diagnosis who present to addiction services have optimum access to mental health services for assessment and treatment. However, one problem that has persisted is that of people with substance-induced psychiatric disorders who have a high risk of self-harm and harm to others and who are often not accepted by mainstream mental health services. From the perspective of addiction services, the introduction and implementation of the National Treatment Agency for Substance Misuse's (2002) models of care framework could address these difficulties. Commissioners and providers of services should consider how to integrate the guidance on dual diagnosis (Department of Health, 2002a ) with the models of care framework to create a single policy document that also addresses referral to mental and addiction services from primary care.

MCQs

1. 1 Studies of dual diagnosis have shown that:

   1. a the prevalence of substance misuse in psychotic disorders is of the order of 10%

   2. b psychotic disorders are most commonly associated with cannabis use

   3. c there is a strong association with antisocial personality disorder

   4. d substance-induced psychiatric disorders predominate

   5. e there is a strong association with suicide.

2. 2 Concerning national policies on the provision of services for people with dual diagnosis:

   1. a the National Service Framework provides important guidance

   2. b services should be provided within mainstream mental health services

   3. c there is strong evidence for the effectiveness of integrated models of care in the UK

   4. d addiction services have a prime role in the provision of training and supervision of staff

   5. e models of care advocate integrated care pathways with enhanced care coordination for this population.

3. 3 Practical clinical assessment of people with dual diagnoses includes:

   1. a screening with the Chemical Use, Abuse and Dependence (CUAD) scale

   2. b screening with the Alcohol Use Disorders Identification Test (AUDIT)

   3. c administration of the Psychiatric Research Interview for Substance and Mental Disorders (PRISM)

   4. d detailed assessment of substance misuse and its interaction with other psychiatric disorders and of risk behaviour

   5. e eanalysis of hair rather than urine for drugs.

4. 4 Treatment for substance misuse in severely mentally ill people includes:

   1. a in-patient treatment as an essential component

   2. b a long-term perspective for lapsing and chronic disorders

   3. c close liaison with the criminal justice system

   4. d the enhanced care programme approach

   5. e community residential care and a stable living situation.

5. 5 Concerning the treatment of people with dual diagnosis:

   1. a motivation interviewing is a core approach

   2. b there is evidence for the efficacy of family therapy

   3. c clozapine is particularly advocated for those with schizophrenia and comorbid alcohol misuse

   4. d cognitive–behavioural techniques are optimally matched to the relapse prevention stage of treatment

   5. e assertive outreach is a key principle.