Adverse childhood experiences and hippocampal volumetric reductions: MRI study

I'm in a 12-Step program for an addiction (have been since 1998), and have met hundreds of other 12-steppers over the years in multiple fellowships. I see two incredibly common traits among members:

1. A significant majority have ADHD.

2. A significant majority have experienced childhood trauma of some sort.

Hippocampal damage has been linked to increased hyperactivity and diminution of response inhibition (among other affects, mainly memory related). This is not a surprise.

Are they all addicted to prescription amphetamines now, instead of alcohol? What about cigarettes?