Scaling up Treatment for Co-morbid Mental Disorders

To the Editor:

The article on hazardous drinking and depression by Park et al. (1) was quite interesting and informative. The finding of severe symptoms and greater burden of illness in persons with depression and comorbid problematic drinking reinforces current understanding of this common form of heterotypic comorbidity. The co-occurrence of mental health problems with hazardous drinking in this study raises important questions about the etiology of mental and substance use disorders (2). The etiology of these comorbid disorders is most likely multi-factorial involving interactions between biological (genetic), psychological and social factors (for example, childhood abuse, trauma, poverty, lack of social capital). Genetic epidemiological studies suggest that alcohol dependence and depression are not transmitted independently, but the genetic and specific environmental sources of liability to major depression overlap with those underlying alcohol dependence (3). Several explanations have been suggested for the occurrence of mental health problems among alcohol users. An important one is the "shared vulnerability model" that posits that there are underlying genetic or other general susceptibility traits that contribute to both alcohol use and observed psychological or behavioural disturbances (4). Another possibility is that some psychiatric disturbances might prompt or increase alcohol consumption. For example, individuals with depressed moods might use alcoholic beverages to self-medicate in 2008 (5). In addition, the social acceptability and availability of alcohol may contribute to the consumption of hazardous quantities. This is more so in many societies where binge drinking is a recognized part of social events and religious ceremonies. In the context of serious mental illnesses like depression, the possibility of hazardous drinking may be increased further by impaired judgment.

Park et al. (1) also observed that 'cross-cultural differences can contribute to the under-diagnosis of depressive disorder and close relationship between hazardous drinking and suicidal ideation in Korea'. This is more so in societies where mental illness is heavily stigmatized and suicidality is not often expressed publicly. In view of this, the authors could have provided more information on the drinking patterns in Korea since drinking patterns have been consistently reported to vary by culture and geographical locations (6). For instance, alcohol is rarely consumed on a daily basis in Mexico, rather its use is usually linked with special occasions including weekends, festivities and paydays during which large amounts are consumed. This drinking pattern contrasts with findings in some parts of Europe for example, France and Portugal where drinking is well integrated into everyday activities (7).

Clearly, the relationship between alcohol use and depression has been confounded by genetic, personality and environmental factors that will continue to require additional research and attention. Nevertheless, the article provides some evidence for integrating screening for alcohol related problems during mental health assessments. There may also be a need for community based interventions focused on changing societal attitude to mental illness in order to improve social support available for persons with depression and/or problematic drinking (8). Better understanding and management of comorbid mental conditions may potentially reduce morbidity and mortality in persons with mental disorders.