Substance Use Disorders in Patients With Anxiety Disorders
Substance Use Disorders in Patients With Anxiety Disorders
Patients who seek treatment for anxiety disorders often have problems with alcohol or drug abuse and are otherwise at an increased risk for developing such problems. Therefore, it benefits mental health practitioners to be aware of the following:
• The specific prevalence of substance use disorders among those with anxiety disorders
• How to reliably identify comorbid drug and alcohol use disorders in patients with anxiety disorders
• The signs of elevated risk of substance use problems developing in patients with anxiety disorders
• How to respond clinically when comorbid drug or alcohol problems exist or when there is a high risk of such problems to develop
In this article, we attempt to leverage state-of-the-art research findings to provide empirically informed perspectives and practices related to these issues. Toward this end, we draw heavily on our own research (funded by the National Institute on Alcohol Abuse and Alcoholism [NIAAA] and National Institute on Drug Abuse) and our clinical experience, as well as on the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC).1
Risk of comorbidity
Substance use disorders (SUDs) occur significantly more often in patients with anxiety disorders than in the general population. Table 1 summarizes the magnitude of these associations for current (ie, past 12 months) diagnoses expressed as odds ratios. The odds of alcohol dependence being diagnosed are 2 to 3 times greater among patients with an anxiety disorder; these correlations are even greater for drug dependence. (Substance abuse—unlike dependence—does not appear to be strongly correlated with anxiety disorders.)
Odds ratios are base-rate neutral by design (ie, they are insensitive to the raw number of individuals classified). Therefore, it is important to know the actual percentage of people with an anxiety disorder who also have an SUD. The Figure shows the 12-month prevalence rates of alcohol and drug dependence in patients with anxiety disorders and in persons in the general population. Table 1 shows greater correlations between anxiety disorders and drug dependence; the Figure shows greater absolute numbers for alcohol use disorder among patients with an anxiety disorder. This reflects the greater overall rate of alcohol-related disorders and suggests that clinicians are 2 to 3 times more likely to see alcohol dependence than drug dependence in their patients with anxiety disorders.
Both Table 1 and the Figure refer to current diagnoses because we considered this time frame to be most relevant to the clinical focus of the article. However, the prevalence of lifetime dependence is obviously higher than that of current diagnoses. In addition, these data do not include patients whose use of drugs or alcohol, while problematic, does not (yet) rise to the level of a DSM diagnosis. By some estimates, this rate could be 3 times greater than that of a diagnosable disorder.2
In addition to current problems associated with drugs and alcohol use among a subgroup of patients with anxiety disorders, it is important to know that there is an elevated risk of future SUDs in all patients with anxiety disorders. Using the student dataset collected by Kushner and colleagues,3 we found that the odds ratios for developing alcohol dependence within 4 to 7 years were 3 to 5 times higher in college freshman with an anxiety disorder than in students who did not have an anxiety disorder. Similarly, Christie and colleagues4 found that individuals between the ages of 18 and 30 who had an anxiety disorder experienced a 2- to 3-fold increased risk of later development of drug dependence.
Some patients with anxiety disorders are at greater risk for SUDs. For example, we found that the 20% of patients with anxiety disorders in the NESARC sample who endorsed using alcohol to self-medicate anxiety symptoms had a much greater risk than others with anxiety disorders of developing a new SUD within the next 3 to 4 years.5 We also found that the number of lifetime internalizing disorders (eg, common anxiety disorders, mood disorders) is a more powerful predictor of SUD risk than is the type of anxiety disorder.6 Finally, the risk of future SUDs among persons with anxiety disorders should also be expected to covary with all of the usual signs of risk, including a positive family history, binge drinking (ie, 5 or more drinks during a single episode) in the past year, a younger age, and being male (Table 2).
All patients with anxiety disorders should be screened for drug- and alcohol-related problems at the initial assessment.7 Because of their prospective risk for an SUD, patients with anxiety disorders seen on an ongoing basis should also have follow-up screening on a routine basis. The most widely used screening tools for alcohol problems include the 4-item CAGE questionnaire (Cut down, Annoyed, Guilty, Eye-opener) and the 10-item AUDIT (Alcohol Use Disorders Identification Test).8,9 A truncated 3-item version of the AUDIT is also recommended by the NIAAA.10 The items from these screening tools are shown in Table 3.
The World Health Organization and the NIAAA have developed the ASSIST (Alcohol, Smoking and Substance Involvement Screening Test) to quantify drug-related risk and behavior of patients (Table 4).11 The patient is first asked about lifetime and previous 3-month substance use by class (eg, marijuana, pain medication, prescription stimulants, cocaine). For each class of drug that is endorsed, additional ASSIST questions are asked.
Causes for comorbidity
Drinking to cope. The view that individuals with anxiety disorders are at risk for SUDs because of escalating substance use aimed at “self-medication” is ubiquitous relative to its limited empirical support. Although it is clear that alcohol’s acute effects can include attenuation of stress and anxiety responding, there is little evidence that this effect alone accounts for the progression to alcohol and drug dependence among those with anxiety disorders.12,13