Figure 5.

Hierarchical age-period estimates, by parental education, of period effects of loneliness among 8th, 10th, and 12th graders in the Monitoring the Future Study (1991–2019), adjusted for self-reported frequency of attaining ≥7 hours of sleep nearly every day or every day. The models also were adjusted for sex (male vs. female), race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic, other races or ethnicities), grade point average (B– or less vs. B or higher), survey implementation technique (paper vs. tablet), and past-year cannabis/alcohol/other drug use. Drugs in the “other substance use” category varied by grade: For 12th graders, we included lysergic acid diethylamide, other hallucinogens, cocaine, amphetamines, sedatives, tranquilizers, heroin, narcotics, crack, and other forms of cocaine. We did not include heroin, narcotics, or sedatives for 8th and 10th graders (parental education is less than college, n = 102,629; for parental education is college or more, n = 126,717).