Is addiction always indicative of mental issues?

I have been thinking about this a lot lately. Obviously addiction is a hallmark feature of mental health issues/disorders.

However… is it possible to develop an addiction simply because you just absolutely love drugs and the way they make you feel? I’ve accomplished a lot for my age and check the boxes for all of society’s indicators of success, but I’ve never really got the same zest out of life that others do. Never felt like celebrating any of my achievements. Drugs just make me feel whole.

I’ve struggled with polysubstance abuse for years, never really relying on one substance class. Opioids were the closest I got to full blown addiction.