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Diagnosis and management of comorbid psychotic and alcohol use disorders

Published online by Cambridge University Press:  01 September 2025

Asimina I. Karampela*
Affiliation:
A fourth-year medical student at Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK. She has an interest in adult psychiatry.
Amy Martin
Affiliation:
A consultant in general adult psychiatry with NHS Lothian, based at the Royal Edinburgh Hospital, Edinburgh, UK. She has a special interest in substance misuse.
Stephen M. Lawrie
Affiliation:
Head of the Division of Psychiatry and Professor of Psychiatry & Neuro-Imaging at the University of Edinburgh, Edinburgh, UK and an honorary consultant psychiatrist with NHS Lothian, Edinburgh, UK, in which capacity he works as a sector-based general adult psychiatrist. He is particularly interested in clinical applications of brain imaging in psychosis and in the development of novel treatments that might enhance outcomes in established schizophrenia and possibly even prevent psychosis in high-risk populations.
*
Correspondence Asimina I. Karampela. Email: ha20692@qmul.ac.uk
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Summary

Alcohol use disorders (AUDs) often coexist with psychotic disorders. Both are common and each can cause or perpetuate the other. Comorbid diagnoses are multifactorial in origin, and both diagnostically and therapeutically challenging. This article is a narrative review of the epidemiology, diagnosis and management of comorbid AUDs and psychotic disorders. Although there is a lack of robust evidence on many aspects of this association, AUDs have been repeatedly shown to worsen outcomes in individuals with schizophrenia. The importance of a rigorous approach to diagnosis is emphasised. Three main treatment strategies emerge: considering particular antipsychotic drugs, relapse-prevention medication and engagement with a number of psychosocial interventions.

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Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of Royal College of Psychiatrists

LEARNING OBJECTIVES

After reading this article you will be able to:

  • understand that AUDs are widespread in individuals with schizophrenia, with an estimated 20% having a lifetime diagnosis of AUD

  • recognise the role of the AUDIT screening tool in identifying potential AUD

  • appreciate that although current guidance focuses on treating the two disorders separately, emerging evidence renders some interventions appropriate for both clinical entities.

Alcohol excess adversely affects the course of schizophrenia and related psychoses. Alcohol-induced psychotic disorder (AIPD) is associated with increased hospital readmissions, suicidal behaviour and mortality (Jordaan Reference Jordaan and Emsley2014). The co-occurrence of an alcohol use disorder (AUD) and a psychotic disorder is also important in terms of self-harm and risk to others (Mulligan Reference Mulligan, Varese and Harris2024). Both psychotic disorders and AUDs are associated with crime, and the combination even more so. Individuals with psychotic disorder are more likely to be a victim of crime than the general population, and the odds are further increased if they have an AUD (de Vries Reference de Vries, van Busschbach and van der Stouwe2019).

In this review, we will consider the management of schizophrenia and related disorders in those with varying degrees of problematic alcohol use. In ICD-11 ( World Health Organization 2025), the term ‘disorders due to use of alcohol’ (6C40) replaced ‘alcoho-related disorders’ (F10), used in ICD-10 (World Health Organization 1993). ‘Alcohol abuse’ (F10.1) was also included in ICD-10, but not in ICD-11. AUD is characterised by impaired control over alcohol consumption, physical dependence (evidence of withdrawal symptoms on reduction/cessation of alcohol), tolerance and negative impact on social, occupational or recreational activities. AUD is further categorised into mild, moderate and severe. AIPD is a distinct psychiatric disorder characterised by auditory hallucinations and persecutory delusions in clear consciousness and the absence of thought disorder in individuals with heavy alcohol consumption (Jordaan Reference Jordaan and Emsley2014).

Epidemiology

Alcohol use disorders (AUDs)

Alcohol use is a major cause of disability and mortality in the UK and around the world. There were 10 473 alcohol-specific deaths recorded in the UK in 2023 (15.9 deaths per 100 000 population) – the highest number on record (Office for National Statistics 2025). It is important to note that AUDs are associated with a range of psychiatric comorbidities, including personality disorders, other substance use disorders (SUDs), anxiety and depression (Yule Reference Yule and Kelly2019).

AUDs and psychotic disorders

Alcohol use disorder is the second most common comorbidity in people with schizophrenia, after nicotine dependence. An analysis of data from World Mental Health Surveys across 18 countries (Degenhardt Reference Degenhardt, Saha and Lim2018) found that AUDs were associated with a roughly 1.6 times higher adjusted risk of psychotic experiences, and that psychotic experiences conferred a 1.5 times higher risk of having an AUD, indicating a bidirectional relationship. A family history of AUDs in those with schizophrenia increases the risk of comorbidity but the reverse association is not clearly established (Jones Reference Jones, Lichtenstein and Grann2011). Comorbidity in psychotic disorders can also be associated with life experiences that increase the risk of AUDs, for instance low educational attainment (Degenhardt Reference Degenhardt, Saha and Lim2018).

Alcohol-induced psychotic disorder (AIPD)

Alcohol-induced psychotic disorder was found to have a lifetime prevalence of 0.41% in the general population (Perälä Reference Perälä, Kuoppasalmi and Pirkola2010). Risk factors for the development of AIPD can be found in Box 1. A large-scale Finnish study which looked at alcohol-induced psychotic syndrome (AIPS) (defined as alcohol-induced psychotic disorder and/or alcohol-induced delirium) in those with alcohol dependence, found a prevalence of 4.8%, with 4.0% for AIPD and 1.9% for delirium (Perälä Reference Perälä, Kuoppasalmi and Pirkola2010). Among those with alcohol dependence, the odds of having had AIPS were higher in participants who had a low income, had never been married, were unemployed and aged 45–54 years. During their lifetime, all participants with AIPS have had some mental health or alcohol treatment contact, and 82% had received psychiatric hospital-based treatment. However, only 59% had been treated in psychiatric hospital with a diagnosis of any psychotic disorder. Most concerningly, the risk of death during the follow-up period was substantially higher among participants with AIPS compared with those with alcohol dependence and the rest of the study population – 37% of patients with AIPS died during the follow-up period (Perälä Reference Perälä, Kuoppasalmi and Pirkola2010).

BOX 1 Risk factors for developing alcohol-induced psychotic disorder

  • Family history/genetic predisposition

  • Multiple hospital treatments for any psychotic disorder or delirium

  • Younger age at onset of alcohol dependence

  • Low socioeconomic status

(Perälä Reference Perälä, Kuoppasalmi and Pirkola2010)

There are very few neurobiological studies on the pathophysiology of comorbid AUD and psychotic disorders or of AIPD. Functional neuroimaging studies in AUD and in substance-induced psychotic disorder have, however, demonstrated reduced dopaminergic activity compared with schizophrenia, suggesting a different possible pathophysiology of AIPD (Jordaan Reference Jordaan and Emsley2014). Structural neuroimaging studies suggest that multiple neuroanatomical regions and networks are involved in AIPD (Jordaan Reference Jordaan and Emsley2014), but the changes associated with alcohol are concentrated on the prefrontal cortex and white matter (Boer Reference Boer, El Marroun and Muetzel2024). The few available studies of cognition in AIPD suggest that people with the disorder perform similarly to people with schizophrenia and worse than those with alcohol dependence alone (Gicas Reference Gicas, Parmar and Fabiano2022).

Alcohol-induced psychotic symptoms compared with schizophrenia

Over the decades there have been studies looking into the relationship between alcohol-induced psychosis and schizophrenia. Several theories have been proposed. These include that an underlying schizophrenia is triggered by excess alcohol intake, that AIPD is secondary to schizophrenia (‘self-medication hypothesis’), the chance development of schizophrenia in someone who is already alcohol dependent or the toxic effect of the alcohol itself. Subsequent studies have dismissed the concept that underlying schizophrenia is triggered by alcohol excess (Jordaan Reference Jordaan and Emsley2014).

A systematic review comparing hallucinations across diagnostic classes demonstrated that, except for age at onset in late adolescence, there is no single feature characteristic of a diagnosis of schizophrenia (Waters Reference Waters and Fernyhough2017). Among the 21 features of hallucinations in schizophrenia considered, 95% were shared with other psychiatric disorders, 85% with medical/neurological conditions, 66% with drug- and alcohol-related conditions and 52% with non-clinical groups. Nevertheless, those with schizophrenia demonstrated more suspiciousness, thought broadcasting, thought insertion and feelings of alien influence (Waters Reference Waters and Fernyhough2017).

Despite hallucinations and delusions being common in both AIPD and schizophrenia, a review by Jordaan & Emsley Reference Jordaan and Emsley2014, reported that they can be distinguished on aspects of their clinical history (such as age at onset and the temporal relationship between psychotic disorder and excessive alcohol intake) and presentation. Those with schizophrenia have higher levels of delusions of reference and persecution. Also, the absence of thought process disorder, appropriateness of behaviour to the hallucinatory content and rapid recovery make AIPD distinguishable from schizophrenia. Importantly, people with AIPD demonstrate a more favourable outcome (Jordaan Reference Jordaan and Emsley2014).

There is also evidence that AIPD can be distinguished from schizophrenia by the absence of the phenomena described by Bleuler – ambivalence, autism, blunting in affect and thought disorder. Furthermore, the family history is important: those with AIPD are more likely to have a family history of alcohol misuse than of psychosis, and vice versa for those with schizophrenia (Masood Reference Masood, Lepping and Romanov2018).

Effects of AUD on people with schizophrenia

Alcohol has been linked to many different poor outcomes in people with schizophrenia. According to a recent systematic review and meta-analysis, the risk of suicide, attempted suicide and suicidal ideation were all significantly increased with alcohol use in people with a schizophrenia-spectrum disorder (Mulligan Reference Mulligan, Varese and Harris2024). A nationwide population-based study also reported poorer medical outcomes, finding higher rates of both psychiatric admissions and emergency department visits in the comorbid AUD and schizophrenia group compared with the schizophrenia-only group (Ahn Reference Ahn, Choi and Choi2021). Interestingly, the rates for both parameters dropped more noticeably after diagnosis in the comorbid group, potentially indicating better management. The control group, which included patients with schizophrenia but no AUD, showed a higher medication possession ratio (MPR) both before and after the AUD diagnosis of the comorbid group, but the MPR of the comorbid group significantly improved after diagnosis (Ahn Reference Ahn, Choi and Choi2021). The MPR is a measure of adherence to prescribed medication, with higher MPR indicating better adherence (Ahn Reference Ahn, Choi and Choi2021).

There is a consensus in the literature that alcohol use increases the mortality rate in schizophrenia by up to 2.9 times (Correll Reference Correll, Solmi and Croatto2022). A nationwide register-based study found a general increased mortality in people with schizophrenia and AUD, with an elevated risk of death from cardiovascular, respiratory and digestive tract-related causes, but with a reduced risk of suicide (Hjorthoj Reference Hjorthoj, Ostergaard and Benros2015). As regards the impact of this comorbid diagnosis on different aspects of life of the patients, unemployment and divorce are increased, as are depressive symptoms, disruptive behaviours and violence (Ahn Reference Ahn, Choi and Choi2021).

Diagnosis

Schizophrenia with comorbid AUD and AIPD are separate and distinguishable disorders, and it is also important to differentiate them from Wernicke’s encephalopathy, Korsakoff syndrome and alcohol-induced dementia, while recognising that all those with severe AUD could develop these conditions. The hallmarks of Wernicke’s encephalopathy are opthalmoparesis with nystagmus, confusion and ataxia related to thiamine deficiency (Vasan 2024).

Both ICD-10 (F10.5) and DSM-5 (292.1) refer to alcohol-induced psychotic disorder. ICD-10 (F10.159) refers to alcohol abuse with AIPD and DSM-5 (292.1) to substance/medication-induced psychotic disorder. According to ICD-10 (F10.5), psychotic symptoms occurring within 2 weeks of alcohol use, persisting for more than 48 h and lasting for less than 6 months, are the key features of AIPD. Hallucinations, delusions, a clouding of consciousness but not severe confusion are the main manifestations. Alcoholic hallucinosis, paranoia, jealousy and psychosis not otherwise specified can also be present. In contrast, ICD-11 (6C40.6: Alcohol-induced psychotic disorder) stipulates that symptoms must be a direct result of the alcohol and differentiates between alcohol-induced psychosis with hallucinations or delusions. It is stressed that there must not be another mental disorder, other disease or disorder that better explains the symptoms.

DSM-5 also emphasises that the symptoms should not be better explained by another psychotic disorder. These include psychotic symptoms, hallucinations or delusions that develop during or soon after intoxication with alcohol or in response to withdrawal of alcohol. They must be in excess of what would be expected from intoxication or withdrawal alone, with an amount and duration of alcohol consumption judged to be capable of producing psychotic symptoms.

The literature often uses the terms AIPD and alcohol hallucinosis interchangeably, which can add to diagnostic uncertainty. However, they are better acknowledged as potentially overlapping rather than the same (Masood Reference Masood, Lepping and Romanov2018).

Diagnostic screening for alcohol dependence and harmful drinking can be carried out using various tools. The National Institute for Health and Care Excellence (NICE) recommends that for a brief assessment the Alcohol Use Disorders Identification Test (AUDIT) or Severity of Alcohol Dependence Questionnaire (SADQ) are used in general (NICE 2025).

The AUDIT (Box 2) has been developed by the World Health Organization (WHO). It is a useful screening tool to ascertain whether patients are drinking a harmful or hazardous amount of alcohol and identify those who require further assessment for alcohol dependence. During its development, the AUDIT questionnaire was tested on 913 patients in primary care who were consuming alcohol. This demonstrated that when the upper cut-off of ≥8/14 was implemented, the AUDIT had a specificity of 94% and a sensitivity of 92% (Saunders Reference Saunders, Aasland and Babor1993). It is recommended that those who score >20 are considered for further specialist assessment. The obvious limitation of the AUDIT is the time required to elicit answers to and score the ten questions. Alternatively, one key question can be asked about both the frequency and quantity of drinks (question 3).

BOX 2 The Alcohol Use Disorders Identification Test (AUDIT)

The AUDIT screening tool was developed by the World Health Organization and modified for use in the UK. It comprises the following questions:

  1. 1 How often do you have a drink containing alcohol?

  2. 2 How many units of alcohol do you drink on a typical day when you are drinking?

  3. 3 How often have you had 6 or more units if female, or 8 or more if male, on a single occasion in the last year?

  4. 4 How often during the last year have you found that you were not able to stop drinking once you had started?

  5. 5 How often during the last year have you failed to do what was normally expected of you because of your drinking?

  6. 6 How often during the last year have you needed an alcoholic drink in the morning to get yourself going after a heavy drinking session?

  7. 7 How often during the last year have you had a feeling of guilt or remorse after drinking?

  8. 8 How often during the last year have you been unable to remember what happened the night before because you had been drinking?

  9. 9 Have you or someone else been injured as a result of your drinking?

  10. 10 Has a relative, a friend, a doctor, or another health worker been concerned about your drinking or suggested that you cut down?

Each question scores 0–4 points. Scoring: 0–7 points = no current alcohol use disorder (low risk); 8–15 points = hazardous or increasing risk drinking; 16–19 points = harmful or higher risk drinking; 20 or more = possible dependence.

(Office for Health Improvement and Disparities 2023)

Another quick tool that can be used is AUDIT-C, which consists of the following three questions: ‘How often do you have a drink containing alcohol?’, ‘How many units of alcohol do you drink on a typical day when you are drinking?’ and ‘How often have you had 6 or more units if female, or 8 or more if male, on a single occasion in the last year?’. A score ≥5 should prompt completion of the full AUDIT questionnaire (Office for Health Improvement and Disparities 2023).

Treatment

The treatment of comorbid psychotic disorder and AUD is complex. Although schizophrenia and schizoaffective disorder alongside AUD may be treated by addressing each disorder separately, it is beyond the scope of this review to describe this and we will focus on how to manage comorbid psychotic disorders and AUD concurrently. Nevertheless, it is worth mentioning that treating one problem may reduce the impact of the other. We will also outline the treatment of AIPD.

Medical treatment of alcohol withdrawal and Wernicke–Korsakoff syndrome

Alcohol withdrawal is potentially life threatening and can be treated with a benzodiazepine, carbamazepine or clomethiazole (CG100: NICE 2010). Wernicke–Korsakoff syndrome should be considered in any patient who is alcohol dependent and confused. If suspected, it is advised to give parenteral thiamine. Oral thiamine can also be offered prophylactically to someone who is alcohol dependent or drinking at harmful levels if they are malnourished or at risk of malnourishment, if they have decompensated liver disease, if they are in acute withdrawal or before and during a planned medically assisted withdrawal (NICE 2010).

Relapse-prevention medication

According to the current NICE guidelines on alcohol-use disorders (CG115: NICE 2011a), acamprosate and naltrexone are offered to only a minority of eligible National Health Service patients, despite being considered effective. To be considered eligible, they should have moderate to severe alcohol dependence, be successfully withdrawn from alcohol and wish to maintain abstinence. Disulfiram can be considered if the above medications are not suitable, or it is the patient’s preference and they are willing to fully be abstinent from alcohol. Again, the dependence should be moderate or severe and the medication should be accompanied by a psychological intervention.

In the following subsections, we outline considerations regarding relapse-prevention medications in the context of the comorbidity.

Acamprosate

Acamprosate is an analogue of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). One study found that acamprosate was no more effective than placebo in reducing drinking or symptoms of schizophrenia, but that it can be safely used in people with alcohol dependence and comorbid schizophrenia-spectrum disorders (Ralevski Reference Ralevski, O’Brien and Jane2011). Acamprosate has also been shown to have neuroprotective properties and therefore has value in those undergoing alcohol detoxification and in relapse prevention (Mason Reference Mason and Heyser2010).

Naltrexone

Naltrexone acts as an opiate receptor antagonist and is therefore thought to reduce the rewarding effects of drinking. A systematic review supported naltrexone’s effectiveness over placebo in terms of reduction in drinking days and the number of drinks consumed on such days, in treating those with AUD and comorbid schizophrenia-spectrum disorder (Sawicka Reference Sawicka and Tracy2017). Comparison of naltrexone with other pharmaceutical interventions showed approximate equivalence with disulfiram, and modest superiority over acamprosate. However, a randomised, double-blind trial (included in Sawicka Reference Sawicka and Tracy2017) involving 31 individuals with schizophrenia and alcohol dependence or misuse who were treated for 12 weeks, reported that participants treated with naltrexone had significantly fewer heavy drinking days, fewer drinking days and experienced reduced cravings compared with the placebo group (Petrakis Reference Petrakis, O’Malley and Rounsaville2004). The review notes that, owing to their design, the included studies were limited to individuals with good engagement with services, with adherence that may not be realised in the real world (Sawicka Reference Sawicka and Tracy2017).

A more recent systematic review and meta-analysis revealed that 50 mg per day of oral naltrexone and acamprosate two tablets of 333 mg acamprosate, given three times per day, improved alcohol consumption-related outcomes compared with placebo (McPheeters Reference McPheeters, O’Connor and Riley2023) in adults with AUD.

Disulfiram

Disulfiram works as a deterrent medication. A randomised controlled trial has been carried out to evaluate the use of disulfiram and naltrexone in people with alcohol dependence and Axis I mental disorders. It showed that those who had a psychotic spectrum disorder had worse alcohol-use outcomes compared with individuals with non-psychotic spectrum disorders. However, they had better alcohol-use outcomes on an active medication compared with placebo, although there was no clear superiority of disulfiram, naltrexone or the combination. Both medications were well tolerated, with medication adherence over 80%. (Petrakis Reference Petrakis, Nich and Ralevski2006).

There have been concerns that disulfiram could worsen psychosis, owing to its inhibition of dopamine beta-hydroxylase, but this seems to be rare in clinical practice (Archibald Reference Archibald, Brunette and Wallin2019). Further research is needed to establish whether disulfiram should have a prominent role in the treatment of AUD since all reported studies to date have significant limitations (McPheeters Reference McPheeters, O’Connor and Riley2023).

Baclofen

Although baclofen has not been licensed for use in AUD in the UK or in most of the world, it has been used as a treatment strategy for alcohol dependence. Despite the fact that it was associated with significantly lower rates of return to any drinking in 13 double-blind randomised controlled trials, evidence has not shown a clear benefit compared with placebo because of inconsistency of results (McPheeters Reference McPheeters, O’Connor and Riley2023). In terms of dosing, there is no established universally approved dose, in part because of the interindividual variability in baclofen pharmacokinetics. There is also a problematic side-effect profile, including seizures, respiratory depression with sleep apnoea and potentially coma, mania, depression and delirium (de Beaurepaire Reference de Beaurepaire, Sinclair and Heydtmann2019).

Other

Nalmefene is approved by NICE for reducing alcohol consumption in people with alcohol dependence who do not require immediate detoxification but have a high-risk level of drinking; it should only be prescribed in combination with ongoing psychosocial support (TA325: NICE 2014).

Although not used in the UK, topiramate or gabapentin are suggested in the USA for patients with moderate to severe alcohol use disorder who have a goal of reduced consumption, if it is their preference or they are unresponsive to naltrexone and acamprosate (DSM-5: American Psychiatric Association 2013).

Antipsychotic medication

Alcohol dependence

A systematic review and meta-analysis of antipsychotics for alcohol dependence showed that, apart from one isolated outcome, antipsychotics did not reduce drinking and did not improve craving or abstinence rates (Kishi Reference Kishi, Sevy and Chekuri2013).

Comorbid AUD

A review of the pharmacotherapy of schizophrenia with comorbid SUD reported that tricyclic antidepressants given in addition to antipsychotic maintenance therapy showed efficacy in reducing substance use and craving (Wobrock Reference Wobrock and Soyka2008). The review authors concluded that although there is a theoretical argument for the use of second-generation antipsychotics, the evidence is weak. They advocated early initiation of treatment with antidepressants, if indicated, as well as a relapse-prevention medications.

A long-term prospective study has reported that aripiprazole in a once-monthly prolonged-release injectable formulation (AOM) improved global functioning in people with schizophrenia both with and without comorbid substance use (Margolese Reference Margolese, Boucher and Therrien2022). Supporting this, a 6-month study found AOM to reduce disease severity scores by more than 30% and to markedly improve daily functioning in people with schizophrenia and comorbid SUDs, including alcohol users (Szerman Reference Szerman, Basurte-Villamor and Vega2020). The benefit of using injectable antipsychotics compared with oral ones has been demonstrated in Canadian study including patients with first-episode psychosis and an SUD, where markedly lower relapse rates, longer relapse-free survival time and reduced hospital readmission rates were observed in people taking the injectable treatment (Abdel-Baki Reference Abdel-Baki, Thibault and Medrano2020). In this study the most common substance misused was cannabis, followed by alcohol.

Clozapine may be another option for individuals with comorbid AUD and a diagnosis of either schizophrenia or schizoaffective disorder. Although the potential effect of clozapine in this context is still unknown (CG120: NICE 2011b), a recent large-scale study demonstrated that clozapine treatment of people with schizophrenia and an SUD reduced the risk of psychiatric hospital admission. Additionally, it was demonstrated that participants with schizophrenia taking clozapine had a reduced risk of developing an SUD compared with no clozapine use or use of other antipsychotics (Lahteenvuo Reference Lahteenvuo, Luykx and Taipale2022).

Nevertheless, motivation is an important factor, as clozapine can only be prescribed to patients who are highly motivated to manage their illnesses and to participate in treatment, consequently resulting in better outcomes for this treatment group. Most reported studies were performed in polysubstance users; therefore, it is difficult to form conclusions specifically for AUDs. Polysubstance use may also result in several interactions affecting the mechanism of action of the antipsychotics, therefore complicating the interpretation of findings (Arranz 2018).

Another antipsychotic, lurasidone, was shown to improve psychopathological burden, positive symptoms and substance craving, although high drop-out rates were noted (Cavallotto Reference Cavallotto, Chiappini and Mosca2024).

Importantly, a review of literature on medications for AUD and mental health conditions demonstrated that medication alone, without the psychosocial interventions, may not lead to stabilisation of both conditions (Yule Reference Yule and Kelly2019).

Services for comorbid psychiatric and SUDs

It is widely recognised that people with both a severe mental health problem and substance misuse should be able to access care to meet their treatment needs. Although mental health services will often lead the care, it is expected that those working in drug treatment should be aware of how to access mental health services and carry out a mental health assessment. It is recommended that if additional psychiatric input is required after a drug treatment team assessment of symptoms or routine screening or because of an existing diagnosis of substance misuse, then drug services should either provide treatment for the mental illness or make appropriate referrals to local psychiatric services (Department of Health 2017).

According to NICE (CG120: NICE 2011b), healthcare professionals should ensure that patients with a comorbid psychiatric disorder and SUD should be offered evidence-based treatments for both conditions. When developing a personalised treatment plan, the severity of both diseases, the individual’s social and treatment context as well as their readiness for change should be taken into account. Also, interactions between the substance being misused and the medication taken should be accounted for and the patient should be informed about potential risks. Last, specialist substance misuse services are advised to provide training for healthcare professionals working in mental health services. The different treatment strategies recommended by NICE are listed in Box 3.

BOX 3 Treatment strategies for comorbid psychotic disorders and alcohol use disorder

  • Treat alcohol withdrawal

  • Consider appropriate relapse-prevention medication

  • Recommend mutual aid organisations, e.g. Alcoholics Anonymous or SMART recovery

  • Offer psychological therapies, e.g. brief motivational interviewing or cognitive–behavioural therapy

  • Monitor antipsychotics if already prescribed for psychosis – but need to consider potential harm through side-effects

(NICE 2011b)

Psychosocial interventions

As suggested in NICE CG115, psychological interventions are important treatment strategies for both primary and comorbid alcohol dependence (NICE 2011a). However, current evidence is considered of low or very low quality (Hunt Reference Hunt, Siegfried and Morley2019). A recent systematic review reported drop-out rates as high as 27% (Bouchard Reference Bouchard, Lecomte and Cloutier2022).

The 3-year report of an important seminal study, Project MATCH, demonstrated that out of 12-step facilitation (TSF), cognitive–behavioural therapy (CBT) and motivational enhancement therapy (MET) there were no major differences among the treatments. However, TSF continued to display a potential advantage compared with the others, also in line with the 1-year report. Comorbid alcohol dependence was not assessed (Project MATCH Research Group 1998).

Although NICE guidelines do not provide a clear algorithm for managing the specific comorbidity, a patient-based approach focused on having a clear care plan for the individual is suggested in NG58 (NICE 2016), agreeing with NICE CG120 (NICE 2011b) in stating that evidence suggests that both psychosis and substance misuse can improve if adverse social and environmental factors are addressed.

Last, it is specified that although psychosocial interventions are recommended for the treatment of substance misuse, with contingency management showing particular promise, they have not been adequately tested for the comorbidity with psychosis (NICE CG120).

12-step approach/mutual aid organisations

The 12-step approach for maintaining abstinence has been adapted for those with SUDs and mental health conditions, forming Dual Recovery Anonymous (https://draonline.org), Dual Diagnosis Anonymous (https://www.ddauk.org) and Double Trouble in Recovery (https://dtrky.org/). Evidence showed that patients had better outcomes in terms of abstinence, personal functioning and adherence to psychiatric medication if they attend a dual-focus group compared with Alcoholics Anonymous (Archibald Reference Archibald, Brunette and Wallin2019). Mutual aid groups aimed at those with co-occurring conditions are less common than the 12-step approach for AUD alone (Yule Reference Yule and Kelly2019). Nevertheless, a meta-analysis reported evidence that those with an AUD and a mental health condition still benefit from engaging with Alcoholics Anonymous, although only 4 out of the 22 included studies related to schizophrenia (Tonigan Reference Tonigan, Pearson and Magill2018). Despite the ongoing research, according to NICE (NG58: NICE 2016), Alcoholics Anonymous is still not included in the guidelines owing to insufficient evidence.

Assertive community treatment

Assertive community treatment offers a more intensive, integrated approach to community mental health service delivery. There is evidence that the assertive community treatment model can improve outcomes for individuals with a diagnosis of AUD comorbid with schizophrenia or schizoaffective disorder (Archibald Reference Archibald, Brunette and Wallin2019). However, NG58 addresses the weak to moderate evidence for this intervention and its limited use in the UK (NICE 2016).

Psychological therapies

The use of CBT in AUD is based on the theory that alcohol dependence is due to both maladaptive habits and a physiological response to alcohol. Alcohol can provide a coping strategy to manage peer pressure, unpleasant feelings or difficult situations.

A systematic review demonstrated that individuals with psychotic disorders and excessive alcohol consumption are responsive to psychological therapy (Baker Reference Baker, Hiles and Thornton2012). The latter took the form of brief motivational interviewing and longer courses of CBT. Brief interventions, of 1–2 sessions, were as effective as 10 sessions. The review suggested, however, that longer psychological input improved functioning and depression.

Psychosocial interventions, among them motivational interviewing, CBT and skills training, for people with AUDs and severe mental illness have also been the subject of a Cochrane review (Hunt Reference Hunt, Siegfried and Morley2019). The authors concluded that there was no substantial evidence to support one psychosocial intervention over another to optimise engagement in treatment, improve the mental state of individuals with severe mental illness or lessen substance use.

Treatment of AIPD

Evaluation of the optimal treatment strategies for alcohol-induced psychosis has proven problematic. A relatively recent systematic review found the evidence to be inconclusive. The authors cited the main reason as low numbers of participants, potentially due to recruitment and retention, but also recognised that achieving prolonged abstinence can be challenging (Masood Reference Masood, Lepping and Romanov2018).

Antipsychotic medication

Antipsychotic treatment together with alcohol abstinence remains a treatment for AIPD, but there is a lack of convincing evidence to support this strategy (Jordaan Reference Jordaan and Emsley2014). A systematic review of AIPD treatment found inconclusive results, although larger studies tend to report at least partial remission on antipsychotic medications, whether in combination with other treatments or as monotherapy (Masood Reference Masood, Lepping and Romanov2018). Nevertheless, the authors highlighted that if a patient showed only a slight or no response to an antipsychotic it was difficult to justify the continuation of that form of treatment.

Abstinence alone

The above-mentioned systematic review also examined abstinence alone as a treatment goal for AIPD (Masood Reference Masood, Lepping and Romanov2018). This would be a safe treatment strategy and, if effective, would have clinical and resource implications, but the review found no studies looking at abstinence without drug treatment.

Conclusions

It is clear that harmful alcohol use or alcohol dependence with comorbid psychotic disorders are both complex and challenging to treat. Despite evidence that this dual diagnosis is common and associated with adverse outcomes, there is a lack of robust evidence on treatment of this double diagnosis as one. Treatment options are further complicated by the individual’s motivation, other comorbidities and social circumstances. However, it is important that these individuals access support to address their alcohol problems. There is evidence that naltrexone and acamprosate are safe and effective in this patient group, as AUD relapse-prevention medication. Regarding psychosocial interventions, psychological therapies were found to be moderately helpful. If there are symptoms of depression, then use of an antidepressant is evidence-based. The evidence is mixed regarding antipsychotics and there is some suggestion that clozapine and once-monthly injectable aripiprazole may be the most effective if there is a comorbid schizophrenia. However, issues with adherence and monitoring may mean this is not a realistic option. Recognising AUDs and psychotic disorders as a clinically significant comorbid entity – and advancing our understanding of their shared pathophysiological mechanisms – will facilitate the development of tailored therapeutic strategies for affected individuals.

MCQs

Select the single best option for each question stem

  1. 1 The likelihood of those with alcohol dependence developing alcohol-induced psychosis is increased if they:

    1. a have a low income

    2. b have never married

    3. c are unemployed

    4. d are middle aged

    5. e meet all of the above criteria.

  2. 2 Considering the psychopathology of people with schizophrenia or alcohol-induced psychotic disorder (AIPD):

    1. a both groups present with the same symptoms

    2. b people with schizophrenia show less suspiciousness than those with AIPD

    3. c thought broadcast is more common in schizophrenia than in AIPD

    4. d delusions of reference are less common in schizophrenia than in AIPD

    5. e age at onset is older in schizophrenia than in AIPD.

  3. 3 The cut-off score on the AUDIT screening tool that suggests alcohol dependence is likely is:

    1. a 10 or above

    2. b 15 or above

    3. c 20 or above

    4. d 25 or above

    5. e 30 or above.

  4. 4 Which of the following is not part of the clinical presentation of Wernicke’s encephalopathy?

    1. a confusion

    2. b opthalmoplegia

    3. c ataxia

    4. d thiamine deficiency

    5. e urinary incontinence.

  5. 5 According to NICE guidelines, who is eligible for acamprosate or naltrexone for alcohol use disorder (AUD)?

    1. a individuals with moderate to severe alcohol dependence, who have successfully withdrawn from alcohol and wish to maintain abstinence

    2. b individuals with mild alcohol dependence

    3. c individuals who are not willing to remain abstinent, but have already tried psychological therapies unsuccessfully

    4. d any individual with AUD who requests these medications

    5. e any individual with AUD who requests these medications and agrees to be adherent.

MCQ answers

  1. 1 e

  2. 2 d

  3. 3 c

  4. 4 e

  5. 5 a

Data availability

Data availability is not applicable to this article as no new data were created or analysed in this study.

Author contributions

A.I.K. and A.M. drafted the article, with written contributions from S.M.L. All authors agreed the final content.

Funding

This research received no specific grant from any funding agency, commercial or not-for-profit sectors.

Declaration of interest

None.

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