“The significance of this article lies in its translational quality (i.e., taking epidemiologic findings and applying them to the bedside where patients can be helped).”

This study, based on the largest alcohol, drug, and mental comorbidity survey ever conducted worldwide to date (the National Institute on Alcohol Abuse and Alcoholism’s National Epidemiologic Survey on Alcohol and Related Conditions-NESARC) was the first and only nationally representative sample (N=43,093) of the U.S. population to use definitions newly provided in the most current psychiatric nomenclature of the American Psychiatric Association (the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition, APA 1994) to separately define and distinguish between DSM-IV major mood (i.e., major depressive disorder, bipolar I, bipolar II, hypomania, and dysthymia) and anxiety (i.e., generalized anxiety disorder, panic disorder with and without agoraphobia, social phobia, specific phobia) disorders that were: substance-induced, defined as mood or anxiety disorders that are due to alcohol/drug withdrawal or intoxication, or due to a general medical condition; from independent mood and anxiety that were not substance-induced or due to a general medical condition. This differentiation is important because we need to know if substance use disorders (abuse and dependence) are related to mood and anxiety disorders even when substance-induced mood and anxiety disorders are excluded from examining the associations. Substance-induced mood and anxiety disorders are not true or independent mood and anxiety disorders but rather mimic symptoms of true mood and anxiety disorders through symptoms of withdrawal and intoxication. So, the methodology used to differentiate between true or independent mood and anxiety disorders and those that are substance-induced (including those due to a general medical condition) was a technological advance that other researchers can use in future research. 

The second technological advance was in the measurement of DSM-IV alcohol and drug use disorders (together called substance use disorders). Unlike previous measures of substance use disorders, our new measures: (1) were drug specific, that is, we measured diagnostic criteria for DSM-IV abuse and dependence on alcohol and 10 drug categories separately so we could derive separate estimates for abuse and dependence on alcohol and each drug; (2) we measured alcohol and (each) drug dependence as syndromes, or the required number of criteria occurring in any one year of the respondent’s life.

The significance of this article lies in its translational quality (i.e., taking epidemiologic findings and applying them to the bedside where patients can be helped). Although the NESARC was the first to differentiate mood and anxiety disorders that were true and substance-induced, several clinical studies of great stature had determined that about 60% of all mood and anxiety disorders among alcoholics and drug abusers is (i.e., those with alcohol or drug abuse and/or dependence) were substance-induced. This meant that individuals with alcohol and drug use disorders weren’t being treated as much as they should have been for the comorbid mood or anxiety disorder since most of these mood and anxiety disorders according to these prior clinical studies were substance-induced and importantly, the symptoms of these mood and anxiety disorders would dissipate when the individual stopped drinking and no longer experienced withdrawal or intoxication from alcohol and/or drugs.

We demonstrated in our paper how the methodology used to differentiate substance-induced from true or independent disorder in these clinical studies was wrong and that, more importantly, when our (the correct methodology) was used on a representative sample of the U.S. populations, the percentage of current (12-month) mood and anxiety disorders that were experienced both overall and among individuals with current alcohol and drug use disorders was very small (well less than 1.0%) and certainly no where near the 60% found in clinical studies.

The bottom line: Many more persons with alcohol and drug use disorders will now be treated for their comorbid mood and/or anxiety disorders. As stated in the manuscript: "Moreover, these results strongly suggest that treatment for a mood or anxiety disorder should not be withheld from those with substance use disorders in stable remission on the assumption that the majority of these disorder are due to intoxication or withdrawal. Left untreated, such mood disorders have been shown to lead to relapse of substance dependence and can also be fatal, as many former substance abusers with severe untreated independent depressions will die by suicide. Short of this ultimately adverse outcome, independent mood and anxiety disorders, particularly among individuals who have a comorbid substance use disorder, are immensely disabling."

I have been conducing epidemiologic research of alcohol, drug, and mental health disorders for over 25 years. My entire scientific career is focused on the understanding of the risk factors and causes of these disorders with a view toward prevention and treatment.

As described above, the implications of this study are largely clinical. However, if more individuals with alcohol and drug use disorders can be assured of treatment for their comorbid substance use disorder and mood and/or anxiety disorders—that occur quite frequently—see manuscript for numbers—then the societal and economic costs of substance use disorders and mood and anxiety disorders may be decreased.