The primary aim of this work was to provide researchers who use the SSAGA with a psychometrically valid and well-characterized Internalizing Scale that can be derived directly from the SSAGA without the need for an additional instrument. Because the SSAGA also contains items that can be used to measure externalizing traits, it is hoped that our scale will enable investigators to examine the relationship between internalizing and externalizing characteristics over time, particularly in relation to substance use problems. This paper describes the development, assessment, and characteristics of a SSAGA-based Internalizing Scale for measuring internalizing problematic characteristics that underlie more specific internalizing conditions such as major depressive episode.22,36 We assessed the Internalizing Scale for internal consistency and construct validity. We hypothesized that the Internalizing Scale scores would be higher in females than in males and would be positively associated with alcohol as well as other substance (i.e., nicotine, marijuana) use disorder symptoms and characteristics.
