Indiana University-Purdue University Indianapolis (IUPUI) / This dissertation examines three vulnerable groups’ health and healthcare access. The first research uses the 2002–2011 Health and Retirement Study data to estimate the effects of adult children’s employment on their caregiving to aging parents. State monthly unemployment rates are used as an instrument for employment. Results show that being employed affects neither male nor female adult children’s caregiving to aging parents significantly. The findings imply that the total amount of informal care provided by adult children might not be affected by changes in labor market participation trends of the two genders. The second research studies the labor impact of Colorado and Washington’s passage of recreational marijuana laws in December 2012. The difference-in-differences method is applied on the 2010–2013 National Survey on Drug Use and Health state estimates and the 2008–2013 Survey of Income and Program Participation data to estimate legalization’s effects on employment. The results show that legalizing recreational marijuana increases marijuana use and reduces the number of weeks employed in a given month by 0.090 among those aged 21 to 25. The laws’ labor effects are not significant on those aged 26 and above. To reduce legalization’s negative effects on employment, states may consider raising the minimum legal age for recreational marijuana use. The third research examines disparities in suicidal behaviors between indigenous and non-indigenous adolescents. The study analyzes the 2001–2013 Youth Risk Behavior Survey data. Oaxaca decomposition is applied to detect sources of disparities in suicide consideration, planning, and attempts. The study finds that the disparities in suicidal behaviors can be explained by differences in suicidal factors’ prevalence and effect sizes between the two groups. Suicidal behavior disparities might be reduced by protecting male indigenous adolescents from sexual abuse and depression, reducing female indigenous adolescents’ substance use, as well as involving male indigenous adolescents in sports teams.