Existing theories of student attrition, centered primarily on the undergraduate student experience, posit that attrition is influenced by individual, institutional, and social factors . Institutional factors include program characteristics, administrative policies, and academic requirements, and social factors include peer culture, faculty/staff interactions, and social integration. Individual pre- and post-matriculation factors include demographic characteristics, skills and abilities, goals and expectations, external commitments, and academic history. Largely missing from theories of student attrition are health status and health behaviors, particularly substance use prior to and after enrollment in an academic degree program. The relationship between alcohol and marijuana use and graduate degree completion is likely influenced by demographic characteristics. Both heavy drinking and marijuana use are more prevalent among college males than females , and substance use disorders are associated with being male, white, and unmarried . Having children is associated with a lower prevalence of substance use among both men and women . Demographic characteristics are also associated with graduate school completion, with burnout and attrition highest among women . Attrition is also more common among African-American/Black students , domestic students , and students enrolled in master’s degree programs . This study aimed to fill a gap in the literature by assessing the relationships between alcohol and marijuana use before and after graduate school enrollment and graduate degree completion. It is hypothesized that lower levels of alcohol and marijuana use both before and after graduate school enrollment are associated with graduate degree completion after adjustment for potentially confounding variables.The College Life Study is a longitudinal study of young adults who were recruited from a large, mid-Atlantic university. During the first stage of sampling, a ten-minute survey was administered to all incoming first-time, first-year students ages 17 to 19 that contained questions on demographic characteristics and tobacco, alcohol, and other drug use behaviors. During the second stage of sampling, the sample was stratified by race, gender, and substance use history. Students who had tried a drug or used a prescription drug non-medically at least once prior to college entry were over sampled. A random sample was chosen for longitudinal follow-up, and 1253 students completed a personal interview at baseline [Year 1 ; modal age 18].
Follow-up assessments were then conducted annually from Years 2 through 8 and then again in Years 10 and 12 through face-to-face interviews, self-administered surveys, and web based surveys. Follow-up rates were high,grow tent for sale ranging from 91% in Y2 and 73% in Y12. The university’s Institutional Review Board approved the study, and informed consent was obtained. Additional detail on recruitment methods and follow-up procedures can be found elsewhere . From the original sample of 1253 young adults, 541 participants enrolled in a degree-seeking graduate program at some point by Y10 of the study. Of these, 21 participants were excluded from analyses. Five of these participants were excluded because upon further examination of other assessment responses, they had listed graduate school enrollment by mistake, and one participant was excluded because information on their specific graduate degree type could not be identified. In addition, to ensure participants had adequate time to complete their degree, 15 participants who first enrolled in a doctorate or professional degree program in Y10 were excluded, giving a final analytic sample of 520 participants.Alcohol use was measured annually in Y1-Y12. To assess frequency of alcohol use, participants were asked, “In the past 12 months, on how many days have you drank any drink with alcohol in it?”. To assess quantity of alcohol use, participants were asked the number of drinks they had on a typical drinking day . Data on days used during the past year were used to estimate average alcohol use frequency for descriptive purposes. Marijuana use frequency was assessed annually in Y1-Y12 with the question “In the past 12 months, on how many days have you used any type of marijuana?” . Data on days used during the past year were used to estimate average marijuana use frequency for descriptive purposes. Past-month frequency of both alcohol and marijuana use were also assessed, but because of the high degree of correlation with past-year measures , only past-year variables were used in the analyses. For each participant, alcohol use frequency, alcohol use quantity, and marijuana use frequency were averaged separately for each of two time periods: before and after the first year they indicated enrollment in a graduate degree program. The mean for each of the six separate variables was used to capture variation in substance use during the pre- and post-enrollment periods, particularly because the before enrollment period included the undergraduate college years as well as the interim years after college graduation but before graduate school enrollment.Gender was coded by the interviewer in Y1 as either male or female. Race/ethnicity was measured in Y3, and response options included white; Black/African-American; American Indian or Alaskan Native; Native Hawaiian; Other Pacific Islander; Asian; and Hispanic, Latino, or Spanish. Participants could also write in a response or choose “Don’t Know/Refuse to Answer”. Given that the majority of the sample was non-Hispanic white, race was dichotomized into white and nonwhite. Marital status was measured in Y4-Y8, Y10, and Y12.
Participants indicated whether they were married, divorced, widowed, separated, in a civil union or domestic partnership, or never married. A dichotomous variable was created to represent whether or not participants were married at any point during Y4-Y12. The number of children participants had was measured in Y4-Y8, Y10, and Y12. A dichotomous variable was created to represent whether or not participants ever had children by Y12.Descriptive statistics were used to analyze the distributions of all study variables. Pearson correlation coefficients were used to analyze the relationships between all six alcohol and marijuana use predictor variables. A series of logistic regression models were fit to assess the relationships between alcohol and marijuana use and graduate degree completion. First, in Stage 1, separate logistic regression models were fit to analyze the relationships between each alcohol and marijuana use predictor variable and graduate degree completion while controlling for demographic and program characteristics. Second, in Stage 2, a best- fitting model was obtained by entering each of the six alcohol and marijuana use predictor variables into the model one at a time, retaining any predictor variable that was statistically significant and dropping those that were not significant. All demographic and program characteristic variables were retained in the final model regardless of significance. The Nagelkerke R2 value was used to examine the variance in graduate degree completion explained by the Stage 2 variables. A similar method has been used in prior work by the research team . SPSS Version 24.0 was used for all analyses, and the alpha level was set at 0.05.The majority of the sample was female and non-Hispanic white , with 42% of participants getting married and 14% having children by Y12 . About two-thirds had enrolled in master’s degree programs and 31% had enrolled in doctorate or professional degree programs, with Y5 as the most common year to begin graduate school. The majority of the sample completed their graduate degree by Y12.The majority of participants drank alcohol during at least one year before graduate school enrollment and after graduate school enrollment . Among drinkers, the average alcohol use frequency was about 75 days during the past year before enrollment in graduate school and 88 days during the past year after enrollment . Among drinkers, mean alcohol use quantity decreased from a mean of 3.9 drinks per drinking day before graduate school enrollment to 2.6 drinks per drinking day after enrollment. The typical quantity consumed for male drinkers was greater than female drinkers both before and after graduate school enrollment . Based on past-year data, it was estimated that about 35% of drinkers drank less than weekly and about 24% drank twice a week or more before graduate school enrollment.
After graduate school enrollment, 32% of drinkers drank less than weekly and about 31% drank twice a week or more.As seen in Table 2, marijuana use frequency among users was about the same prior to and after graduate school enrollment with a mean of about 40 days during the past year. Among those who used marijuana prior to graduate school enrollment, 56% used once a month or less and about a quarter used at least weekly . Among those who used marijuana after graduate school enrollment, 64% used once a month or less and about 18% used at least weekly . The correlations between the six alcohol and marijuana use predictor variables are presented in Table 3. There were moderate to strong correlations between the before enrollment estimates and the after enrollment estimates. Despite this statistical overlap, both before and after enrollment variables were retained due to their importance to the research question of interest. Alcohol use frequency before graduate school enrollment was strongly correlated with alcohol use quantity before graduate school enrollment and moderately correlated with alcohol use quantity after graduate school enrollment . To avoid the potential for multicollinearity effects on the statistical models, only the alcohol use frequency variables were retained for further analyses. There is prior evidence that frequency of alcohol use increases during the post-college period while quantity of alcohol use decreases ,indoor grow tent and alcohol use frequency has higher sensitivity and specificity in identifying alcohol-related problems than alcohol use quantity .Stage 1 results showed that, even after controlling for demographic and program characteristics, marijuana use frequency after enrollment was negatively associated with graduate degree completion . The best-fitting model included alcohol use frequency before graduate school enrollment and marijuana use frequency after graduate school enrollment, which were both significantly associated with graduate degree completion after being entered into a model together and with the demographic and program characteristics. Alcohol use frequency before enrollment was positively associated with the odds of graduate degree completion . In contrast, as marijuana use frequency after enrollment increased, the odds of graduate degree completion decreased . In the best-fitting model, gender, marital status, and first year of graduate school enrollment were associated with graduate degree completion.
Female students had almost two times higher odds of graduate degree completion when compared with male students, and married students had more than two times higher odds of graduate degree completion when compared with those who had never been married. In comparison with students who began their graduate degree in Y10 , students entering graduate school in Y5 , Y6 , and Y7 had significantly higher odds of graduate degree completion. 4. Discussion This study examined whether or not alcohol and marijuana use before and after graduate school enrollment were associated with graduate degree completion. Alcohol and marijuana use were moderate among participants in this sample. Results showed that more frequent marijuana use after graduate school enrollment was associated with decreased odds of graduate degree completion after adjustment for potentially confounding variables. This finding is consistent with prior research that has shown a relationship between frequent marijuana use and degree non-completion among high school and undergraduate college students . Marijuana use was less prevalent after graduate school enrollment as compared with before, which is consistent with research showing that marijuana use declines as young adults age . However, while past-year marijuana use frequency among marijuana users who completed their graduate degree declined from 40 days before enrollment to 35 days after enrollment, frequency among users who did not complete their graduate degree increased from 45 days before enrollment to 85 days after enrollment. There are several mechanisms through which marijuana use might affect degree completion. The first is through decreased academic performance, with underachievement cited as the most well-supported correlate of marijuana use . While little research has been done on the relationship between marijuana use and decreased academic performance among graduate students, existing evidence among high school and college students shows that frequent marijuana use is associated with academic unpreparedness , lower grades , and lower academic achievement . The relationship between marijuana use and degree non-completion might also be explained by the effects of marijuana use on cognition .