Severity of Substance Use Disorder: Utility as an Outcome in Clinical Settings

Some authors have pointed out the usefulness of the levels of substance use disorder (SUD) as a treatment outcome. However, in order to use this variable as an outcome measure, its impact needs to be addressed within a clinical context. The aim of this study was to analyze the sensitivity of SUD levels as a measure for detecting reliable changes and to make a comparison between the changes in SUD levels detected when using the number of criteria fulfilled and when using the reliable change index (RCI).

The sample consisted of 206 (106 in follow-up) patients diagnosed with abuse/dependence on alcohol and cocaine, according to DSM-IV criteria. The Substance Dependence Severity Scale for DSM-5 was used to determine current alcohol use disorder (AUD) and cocaine use disorder (CUD). Number of DSM-5 criteria fulfilled and RCI were used to determine the change in SUD levels.

No association was found between adherence to/abandonment of treatment and AUD severity levels (χ²  = 7.029, p = 0.071) or CUD severity levels (χ²  = 2.044, p = 0.413). Statistical significant differences for levels of AUD (z = -3.870, p = 0.000) and CUD (z = -5.382, p = 0.000) were found between baseline assessment and follow-up. According to the number of DSM-5 criteria and RCI, the Kappa coefficient for the change in patient status (improved, worsened, or no change) was k = 0.61 for alcohol patients and k = 0.64 for cocaine patients. The "mild" category showed the greatest inconsistency between both procedures.

Levels of SUD are sensitive to the impact of treatment as measured by the difference between the baseline assessment and 3-month follow-up. However, conclusions differ according to whether the DSM-5 criteria or the RCI is applied.