Here’s a 2011 meta analysis that reports that DRD (delayed reward discounting — basically putting lower importance on delayed gratification and instead putting greater importance on immediate rewards) is highly associated with addictive personalities:

https://addictions.psych.ucla.edu/wp-content/uploads/sites/1...

> Conclusions These results provide strong evidence of greater DRD in individuals exhibiting addictive behavior in general and particularly in individuals who meet criteria for an addictive disorder.