Healthcare use, interventions and longer term outcomes in people with co-occurring bipolar and alcohol use disorders

Since 1990, the global prevalence of bipolar disorder (BD) has increased by 59.3% (GBD Mental Disorder Collaborators, 2019). Across all mental disorders, BD is the third highest cause of disability-adjusted-life years for adolescents and in the top five across the entire lifespan (GBD Mental Disorder Collaborators, 2019). 40-70% of people diagnosed with BD globally suffer from comorbid alcohol use disorder (AUD) (Grunze et al., 2021) with a higher comorbidity than for other mental disorders (Puddephatt et al., 2021). Comorbid AUD problematically influences the clinical outcomes (Salloum & Brown, 2017), increases suicide risk (Oquendo et al., 2010) and lowers treatment adherence (Manwani et al., 2007) in BD. The relationship between AUD and BD is likely bidirectional, with the depressive stages of BD increasing alcohol craving, and alcohol use exacerbating both mania and depression symptoms of BD (Grunze et al., 2021).

There are established inequalities in access to care and treatment experience for people with co-occurring problems (Harris & Edlund, 2005). However, even when someone accesses treatment it typically only targets either mood symptoms or alcohol use outcomes (e.g., Schmitz et al., 2002; Weiss et al., 2007). Indeed, no existing psychosocial interventions consistently benefit both BD and substance use symptoms for patients with co-occurring disorders (Gold et al., 2018).
The above issues are compounded by social inequalities and people of lower socioeconomic status are disproportionately burdened with alcohol-related harms, including mortality (Collins, 2016), and an increased prevalence of severe mental illness, including BD (Lee et al., 2020). Specifically, the North of England reports disproportionately higher rates of mental health conditions, including BD, associated with deprivation, reduced life expectancy and increased suicide risk (Public Health England, 2019). However, evidence for BD treatment effectiveness is biased by research centred around the South of England (UK Clinical Research Collaboration, 2015; MQ, 2019), and health inequalities regarding comorbid AUD and BD remain unexplored. Resultingly, there is a need to review national records to further understand the inequalities that may be experienced by people with comorbid AUD and BD and to investigate how treatment pathways and outcomes may be impacted.