Date of Award


Degree Type


Degree Name

Doctor of Philosophy in Psychology


Clinical Psychology



First Advisor

Mark Robbins


Substance abuse is a growing problem worldwide, and the negative consequences associated with Substance Use Disorder (SUD) impact people across all age groups, but the availability of SUD screening tools that show clinical usefulness across generational differences is limited. Therefore, more research exploring differences and similarities in substance abuse and dependence problems across age groups may provide useful information for future research and clinical work. The present study examines age group differences in substance abuse and dependence behaviors in three main analyses.

First, age differences in abuse and dependence of drug types were examined using Chi-square tests for independence with a sample (N = 1,620) who completed Structured Clinical Interviews for DSM (SCID) interviews as part of the MIDAS study at Rhode Island Hospital. Participants reported on whether they abused different drug types (i.e., sedatives/hypnotics/anxiolytics, cannabis, stimulants, opioids, cocaine, and hallucinogens) in the past year. Crosstabulations comparing abuse and dependence of different drug types across age groups (i.e., ages 18-25, 26-35, 36-49, 50 and older), showed that the middle age group (i.e., ages 36-49) reported significantly higher rates of past-year substance abuse and dependence compared to the other age groups, for drug types including sedative/hypnotics/anxiolytics, cannabis, stimulants, and cocaine. In addition, past-year cannabis abuse appeared to be significantly more prevalent across all age groups compared to other drug types.

Second, the factor structure of a proposed substance abuse problems measure, the Clinically Useful Substance Abuse Problems Outcome Scale (CUSAPOS), was explored with principal components analysis (PCA) and confirmed with confirmatory factor analysis (CFA) in order to evaluate clinical usefulness in an outpatient psychiatric setting. Results from PCAs showed that the proposed CUSAPOS subscales, which assess for alcohol and drug abuse problems, should be treated as two distinct scales, the Clinically Useful Alcohol Problems Outcomes Scale (CUAPOS) and the Clinically Useful Drug Problems Outcome Scale (CUDPOS), each with two factors. Both scales show one factor that appears to describe the level of one’s insight regarding their substance abuse problems, and the other factor assessing for behavioral consequences of substance abuse problems. The factor structure for each scale was confirmed with CFAs examining overall goodness of fit. Multigroup CFA was used to test for invariance of participant responses to these scales across four Age Cohorts including Young Adults (ages 18-25), Adults (ages 26-35), Middle Age (ages 36-49) and Older Adults (ages 50 and older). Results showed that both the CUAPOS and the CUDPOS are non-invariant, suggesting that there may be meaningful differences in the way participants in different age cohorts interpreted and responded to the proposed items in each scale.

Third, after confirming the factor structure of the two distinct scales and establishing that they are both non-invariant across Age Cohorts, differences in participants mean scores were examined between Age Cohorts for both the CUAPOS and the CUDPOS with Analyses of Variance (ANOVAs). Confounding variables that potentially influence relationships between age and alcohol or drug abuse, including Race, Gender, Mood Impairment, Attention Deficit Hyperactivity Disorder (ADHD), Self-Injury, and Childhood Trauma were analyzed using ANCOVAs and two-way ANOVAs. ANOVA results showed that the CUAPOS showed no significant differences in mean scores between Age Cohorts, however an interaction effect between Age Cohort and Race showed that the Young Adult, Persons of Color, group reported significantly less problems than the rest of the Age Cohort and Race groups, whereas the Middle Age, Person of Color group reported significantly more alcohol problems compared to the other groups. The CUDPOS showed significant differences in the mean scores between the Young Adult group and the Middle Age and Older Adult groups. Gender was found to have a significant main effect on CUDPOS scores but showed a nonsignificant interaction effect with Age Cohort. Overall, results showed that the only significant covariate influencing the relationship between the participant responses on the CUDPOS between Age Cohorts was Childhood Trauma. Implications of these findings and study limitations are discussed, as well as suggestions for future research further exploring relationships between age and substance abuse and dependence.



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