Unmet need for treatment for substance use disorders across race and ethnicity

Abstract

Background

The objective was to analyze disparities in unmet need for substance use treatment and to observe variation across different definitions of need for treatment.

Methods

Data were analyzed from the 2002 to 2005 National Survey of Drug Use and Health and the National Epidemiologic Survey on Alcohol and Related Conditions. Logistic regressions estimated the likelihood of specialty substance use treatment across the two data sets. Parallel variables for specialty, informal and any substance abuse treatment were created. Perceived need and normative need for substance use treatment were defined, with normative need stratified across lifetime disorder, past twelve month disorder, and heavy alcohol/any illicit drug use. Treatment rates were analyzed, comparing Blacks, Asians and Latinos to non-Latino whites across need definitions, and adjusting for age, sex, household income, marital status, education and insurance.

Results

Asians with past year substance use disorder had a higher likelihood of unmet need for specialty treatment than whites. Blacks with past year disorder and with heavy drinking/illicit drug use had significantly lower likelihood of unmet need. Latinos with past year disorder had a higher likelihood of unmet need for specialty substance abuse treatment. Asians with heavy drinking/illicit drug use had lower likelihood of unmet need.

Conclusions

The findings suggest that pathways to substance abuse treatment differ across groups. Given high rates of unmet need, a broad approach to defining need for treatment is warranted. Future research to disentangle social and systemic factors from factors based on diagnostic criteria is necessary in the identification of need for treatment.

Introduction

Planning for service provision for drug and alcohol treatment requires precise estimates of unmet need for such treatment (Rehm and Greenfield, 2008, Shepard et al., 2005) broken down by subgroups such as race and ethnicity (Alvarez et al., 2007, Reynoso-Vallejo et al., 2008). Generating such estimates is difficult. Few studies have large enough sample sizes to compare need for treatment for substance use only across racial and ethnic subgroups; hence, many studies combine mental health and substance diagnoses and treatment estimates across groups. Inconsistencies in how need for behavioral health treatment is defined are also evident (Aoun et al., 2004, Sareen et al., 2005), making it difficult to reconcile different findings across groups.

A comprehensive understanding of disparities in need for substance use treatment is necessary. To achieve this goal, researchers must agree on what constitutes need. Some evidence suggests that differential endorsements of symptoms in diagnostic assessments may occur across race/ethnicity and cultures (Alegría and McGuire, 2003, Breslau et al., 2008, Weiss et al., 2003). Hence, restricting need estimates for substance use treatment to those who fulfill the most restrictive diagnostic criteria may undercount need estimates for some subpopulations and bias estimates. Alternately, substance use treatment has a health system function and a criminal justice function, with evidence of disproportionate court-mandated substance use treatment services for Latinos and African Americans compared to non-Latino whites (Rounds-Bryant et al., 2003) which could reflect a social control element embedded in treatment for substance use disorders (Burman, 2004). If some groups are more vulnerable to such social influences, relaxing the diagnostic criteria could lead to artificially inflated and biased rates of treatment use for some groups. It is critical to take into account differences across need definitions when considering disparities estimates.

Two need definitions often used in psychiatric epidemiology are normative need and felt need (Aoun et al., 2004). Normative need is defined by diagnostic criteria determined by experts (e.g., the presence of a psychiatric diagnosis). Felt need (or perceived need) is defined by the subjective opinion that one needs treatment. These definitions are often combined differently across studies, yielding inconsistent conclusions about unmet need for treatment across racial/ethnic groups.

Inconsistencies in need definitions may contribute to contradictory disparities estimates. In the longitudinal household telephone survey, Health Care for Communities, need for treatment services was defined by whether a person thought they needed help (felt need) or probable clinical need (normative need), measured by screening positive for mental health problems and/or alcohol abuse or recent use of illicit drugs. Analyses based on these data showed greater unmet need for treatment among racial/ethnic minorities relative to Whites (Stockdale et al., 2007, Wells et al., 2001). In contrast, other studies using the National Survey of Drug Use and Health (NSDUH), calculated past year unmet need for substance use treatment using only diagnostic criteria from the DSM-IV-R (normative need; Epstein et al., 2004, Wu et al., 2003). These studies found no significant differences in unmet need across race/ethnicity. A third study using the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) defined need according to lifetime diagnoses, and found Blacks were more likely to utilize non-specialty services for drug disorders compared to Whites (Hatzenbuehler et al., 2008). The differences in methodologies make drawing conclusions about disparities in unmet need for substance disorders difficult to disentangle across studies.

Even within normative diagnostic definitions of need, significant variability in criteria used to define need is often evident. Using DSM criteria, definitions of substance use disorders can differ according to whether a respondent meets one or more of six symptoms (Wu et al., 2003) or meets three or more of seven criteria (Harris and Edlund, 2005). However, current APA practice guidelines recommend treating individuals with substance “misuse” without progression to dependence or abuse (American Psychiatric Association, 2006). The critical question is whether variability in substance use treatment disparities across race/ethnicity exists depending upon the cut-off point in the normative definition of need.

The purpose of this analysis is to compare disparities in unmet need for substance use treatment restricted to substance use disorders only, using robust sample sizes to enable comparisons across groups. A related objective is to observe whether disparities estimates vary depending upon the definitions of need for treatment applied. We concentrate on substance use disorders without co-occurring mental health diagnoses because little information exists about treatment patterns for substance use services only across race/ethnicity. Such information is necessary to improve tracking across race/ethnicity and to design more targeted clinical and policy interventions that are culturally appropriate for these populations (Robles et al., 2006).

To provide a comprehensive picture of unmet need, we utilize data from two epidemiologic datasets – the 2002–2005 National Survey of Drug Use and Health (NSDUH) and the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). We match definitions for categories of need and treatment across the two surveys. By conducting parallel analyses with two different surveys, we accomplish two goals. First, we capitalize on the strengths of both datasets, as the NSDUH has a large enough sample size to allow comparisons across ethnic/racial groups in past year diagnoses, and the NESARC has more comprehensive treatment data. Secondly, we enable assessment of a broad range of need definitions, as the NSDUH collects data on perceived unmet need and past year substance diagnoses, while the NESARC includes lifetime substance diagnoses in addition to past year. We estimate disparities using the large samples available in the NSDUH, and check these findings against those in the NESARC as a sensitivity analysis.