Addiction is a biopsychosocial disorder. It's a combination of your genetics, your neurobiology and how that interacts with psychological and social factors. That basically means that addiction is a chronic disorder - like type 2 diabetes, cancer and heart disease. (Maureen Boyle from the National Institute of Drug Abuse)
And also sounds much better then 
I smoked cigarettes, rolled tobacco and now swapped to vaping. Smoking has always been my 5. My five minutes of peace and a short break. It is my start and end point. In my deluded mind it keeps me organized. I finished middle school for nursing, I walked on the hallways of oncology, and I’ve seen how a healthy and smokers lungs look like in the flesh. A friend died of lung cancer just 2 years ago … and while typing all this I just dragged one in.
How my smoking started? Very early actually. It started when I was a baby and I sucked my thumb and to my shame did that for the longest time, even though my parents did everything possible for me to stop. When the thumb was out I started biting my nails. After nails followed my hair and of course through all the stages there was food. Until I found smoking at age 16.
Now by psychology standards this could have simply been my coping skill. A child sucking her thumb for the sake of feeling soothed and calmed like a baby in the womb. Regarding my upbringing that theory was just fine with me and I took it. Until later when I learned about sensory integration and worked with children who had the heaviest mental and physical disability.
Sensory integration is about how our brain receives and processes sensory information so that we can do the things we need to do in our everyday life. There is a theory of sensory integration and a therapeutic approach based on the theory.
In very generalizing and simplistic way explained you all know it. People who can’t sit still for 2 minutes, people you give a gentle tap on the shoulder and scream: auuuuuuu, people who are bothered by sounds or bright light, people who hate socks or specific material, people who don’t like to eat certain structure of food, people who in the middle of winter walk around in shorts, etc. etc.
Simply put we receive or process information we get from our environment differently. The issue occurs where we over or under respond to the stimuli. With children with special needs that is easily spotted. Body rocking, body harm, hand flapping, making noises, etc. Simply stimming themselves in different ways.
Was I simply stimming myself orally all this time? Guess it all depends which expert you ask.
And all of this sounds better than simply -
Done in Corel Painter.