Issue 15, 2006R

Emergency Department Visits Involving Patients With Co-occurring Disorders

Mental health and substance abuse practitioners and researchers have become increasingly conscious of a link between substance use and mental disorders in recent years.¹ A substantial number of persons in the United States experience co-occurring substance use and mental disorders. In 2004, an estimated 4.6 million adults in the United States met criteria for both serious psychological distress (SPD) and substance abuse and dependence.² Approximately 50 percent of persons with a substance use disorder have had a co-occurring mental disorder in their lifetime.³

Individuals with co-occurring substance use and mental disorders often are more difficult to treat and experience worse outcomes than other patients.⁴ Persons with these co-occurring disorders also have higher rates of emergency department (ED) use than those with mental disorders alone.⁵ Identifying those individuals with co-occurring disorders and the problems they experience is essential to developing appropriate treatment strategies at all points of contact, including the ED visit.

The Drug Abuse Warning Network (DAWN) collects data from a national sample of hospitals on ED visits related to recent drug use. Using data on patient diagnoses, we are able to identify those drug-related ED visits where patients were diagnosed with both substance use and mental disorders.⁶ This report presents findings on these ED visits involving co-occurring substance use and mental disorders.

During 2004, an estimated 246,800 patients in drug-related ED visits were diagnosed with co-occurring substance use and mental disorders. This number accounted for nearly 10 percent of all drug-related ED visits. In more than half (57%) of the ED visits with co-occurring disorders, the mental disorder diagnosis was depression. Among diagnoses for substance use disorders, more than half (54%) involved a diagnosis of "drug abuse," and nearly a third (31%) were diagnosed with an "overdose."

However, not all ED visits involving patients with co-occurring disorders will have such diagnoses documented in the ED chart. For instance, a patient with depression controlled by medication may come to the ED for an injury related to his or her abuse of another drug. In such cases, the diagnoses may document drug abuse but not depression.

Patients in age groups between 18 and 54 had similar rates of ED visits with co-occurring disorder diagnoses, ranging from 99 to 179 visits per 100,000 population (Figure 1). In general, the rates for patients aged 18 to 54 were higher than those found for younger patients (aged 12 to 17) and older patients (aged 55 and older), but only the larger differences were statistically significant.

Figure 1. Rates of ED visits involving co-occurring disorders, by age

Source: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2004 (03/2008 update).

Male and female patients experienced similar levels of ED visits with co-occurring disorder diagnoses (Figure 2).

Figure 2. Rates of ED visits involving co-occurring disorders, by gender

Source: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2004 (03/2008 update).

Where ED visits involved co-occurring disorders, 49 percent of patients were admitted to inpatient units, and 37 percent were treated and released (Figure 3). Of patients who were treated and released, most were discharged home (72%), but a quarter (25%) were referred to detoxification or other drug treatment.

Among patients admitted for inpatient care, 72 percent were admitted to psychiatric units. Nearly 10 percent of admitted patients required intensive or critical care.

Figure 3. Discharge status of ED visits involving co-occurring disorders

Source: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2004 (03/2008 update).

Alcohol (in 37% of visits) was the most frequently reported drug for ED visits with co-occurring diagnoses (Table 1). In addition, cocaine, marijuana, and stimulants (in 36%, 18%, and 13% of visits, respectively) also were involved often in co-occurring ED visits. Besides illicit drugs, medically prescribed benzodiazepines (15% of visits) were also among the five drugs most often reported in ED visits for those with co-occurring substance use and mental disorders.