Predictive capacity of a cognitive screen: can the Addenbrooke’s Cognitive Examination - III predict early relapse following inpatient detoxification in severe alcohol dependence?
Background: Alcohol misuse and dependency are major health problems worldwide. Despite the availability of a number of evidence-based treatments for alcohol-dependency, a large proportion of people relapse following detoxification. The costs to society and the individual are vast, not only economically but in terms of social and interpersonal functioning also. There is a recognised need to understand the factors that contribute to poorer outcomes in this population. Cognitive impairment is one factor that has demonstrated considerable associations with poor outcomes in the wider substance-misuse population. Aims: This thesis has two sections. The first comprises a systematic review which aimed to present the objective evidence for emotional decision-making deficits in the alcohol dependent population. The second is an empirical study which aimed to establish whether or not relapse can be predicted in a severely alcohol dependent population in the early stages following inpatient detoxification. In addition, a normative dataset for this clinical population using the ACE-III is presented. Methods: For the systematic review, a structured search of the literature relating to emotional decision-making in alcohol dependent samples was conducted. Iterative application of pre-defined inclusion and exclusion criteria identified eighteen studies for critical review. Quality assessment of these studies was undertaken and validated by means of calculating inter-rater reliability. For the empirical study, two sub-samples of a cross-sectional group of patients being treated for severe alcohol-dependence were examined; one to collate normative data for the ACE-III (N=73) and one to investigate associations between the ACE-III and relapse (N=20), including covariates of age, mood, anxiety and motivation. Results: The systematic review demonstrated substantial support for a deficit in emotional decision-making ability in alcohol-dependence. Methodological quality of the reviewed papers was moderate to high. Deficits in performance on a task of emotional decision-making compared to healthy controls indicated a reduced learning curve in alcohol dependent samples. Limitations of the studies included failure to report power analyses and effect sizes, insufficient detail regarding methodology and exclusion of common comorbidities in alcohol-dependence. The empirical study demonstrated clinically significant cognitive impairment in a sample of severely alcohol dependent individuals in the early stages following detoxification. In a smaller sample, cognitive functioning was not found to be predictive of relapse at one-month post-detoxification. Associations were identified between age and ACE-III score and between age and relapse status. Age was not predictive of outcome. Conclusions: The available evidence points towards the existence of emotional decision-making deficits in alcohol dependent individuals. These are likely to impact on the ability of individuals make the health behaviour changes required to recover from alcohol dependence. Further research may be helpful in identifying factors associated with increased decision-making deficit in this specific population and investigating the processes underlying such difficulties. The clinical normative dataset presented in the empirical study points towards generalised cognitive impairment during the early stages of abstinence which may negatively impact on ability to engage meaningfully with psychosocial interventions. Performance on the ACE-III was not found to predict relapse in the current sample. Previous research would suggest that the links between cognitive functioning and relapse are less well defined in alcohol-misusing samples than in the wider substance-misuse population. Therefore future research may help to clarify this association in alcohol dependent samples. It is acknowledged that the ACE-III is yet to be validated for use in the alcohol dependent population and is limited in its ability to assess executive functions. Given the high prevalence of executive functioning deficits in the alcohol dependent population, it seems of importance to use cognitive screening tools which place appropriate emphasis on these abilities. Service providers are encouraged to incorporate routine cognitive screening into clinical practice and consider the implications of cognitive impairment at both individual and service delivery levels.