Mental Health America has just released the State by State rankings for 2018 mental health. The results are summarized below.

Overall Ranking
A high overall ranking indicates lower prevalence of mental illness and higher rates of access to care. A low overall ranking indicates higher prevalence of mental illness and lower rates of access to care. The combined scores of all 15 measures make up the overall ranking.  The overall ranking includes both adult and youth measures as well as prevalence and access to care measures. 

Illinois is ranked at #11 – improved from #15 in 2017

Adult Ranking
States with high rankings have lower prevalence of mental illness and higher rates of access to care for adults. Lower rankings indicate that adults have higher prevalence of mental illness and lower rates of access to care.

Illinois ranked #6 – improved from #9 in 2017

Youth Ranking
States with high rankings have lower prevalence of mental illness and higher rates of access to care for youth. Lower rankings indicate that youth have higher prevalence of mental illness and lower rates of access to care.

Illinois is ranked #15 – improved from # 18 in 2017

For much more detail about how the data was collected, analyzed etc, click on this link:
State of mental health