another look at the Mental Health Services Act

In the Mental Health Services Act Community Support and Services Plan put out by the Humboldt County Department of Health and Human Services Mental Health Branch, the claim is made that:
“among the estimated 2000 homeless adults, 80% of homeless adults suffer mental health issues; 90% suffer substance abuse.” (page 35)

The overlap (“co-occurrence”) of “mental health issues” and “substance abuse” is estimated at 4% in the MHSAA CSS Plan.

This would mean that 76.8% of homeless adults have “mental health issues” exclusively, 86.8% of homeless adults have “substance abuse” exclusively, and 3.2% of homeless adults have “co-occurring” “mental health issues” and “substance abuse.”

These numbers exceed 100% greatly, and thus are impossible!

Even if we use the estimate of 50% “co-occurring” “mental health issues” and “substance abuse” that is asserted in the “Blueprint for Change: Ending Chronic Homelessness for Persons with Serious Mental Illnesses and/or Co-Occurring Substance Use Disorder” (US Dept. of Health and Human Services), we STILL get numbers greater than 100%!!! (40% exclusively “mental health issues,” 50% exclusively “substance abuse,” and 40% having both.)

Mental Health Services Act Community Support and Services (MHSA CSS) Plan available on the net at: http://co.humboldt.ca.us/hhs/mh/mhsa.asp

“Blueprint for Change: Ending Chronic Homelessness for Persons with Serious Mental Illnesses and/or Co-Occurring Substance Use Disorder” (US Dept. of Health and Human Services) available at:
http://www.mentalhealth.samhsa.gov/publications/allpubs/SMA04-3870/default.asp