Emptiness inside (1) "Reward deficiency"

People have struggled  for a long time to discover what lies behind addictions of all kinds.  Learned journals and countless articles have attempted to clarify what lies behind  these extraordinary behaviors. One such, that captured my attention right at the start of my research in 2002, was written in 1996 and  is about a "Reward deficiency syndrome". 

That resonated with me, because its clear that addictions are an attempt to fill up the emptiness inside.  Womb twin survivors often mention emptiness, or feeling unsatisfied,  and many of these also say that are addicted to substances or behaviors that damage their health, wealth or well-being.  But these scientific research writers know nothing of the inner feelings of womb twin survivors, so the idea that emerges is some kind of "deficiency in the reward system of the brain". Like so many writers on the subject of addiction, they get so very close, but not close enough......