What does reckless behavior have to do with mental health?

A lot. Pull over& listen. You scare me. Do you really think a ''mentally well'' person would drive recklessly? As a psychiatrist, i hope you are kidding me. If not, you walk & think until you understand the death of a child ! go to your nearest morgue & look real good at the gruesome results of reckless driving. Got it? Good.
Depends on behavior. Wonder what you mean by reckless behavior. Some of it has to do with poor impulse control. Some with adrenaline addiction. Some is short term pleasure. Some behaviors have to do with hitting the 'heck with it' button, basically a cast your fate to the wind moment where it's too hard to keep thinking/agonizing over a choice, so you just do it. Take charge over choices, connect to consequences!