Passion has linguistic roots in suffering, and its biological mechanism ties in with addiction. 2

from book The Passion Paradox: A Guide to Going All In, Finding Success, and Discovering the Benefits of an Unbalanced Life

The story of passion is one that stretches back a long way. Although nowadays we tend to view passion as a term with positive attributes, this wasn’t always the case.
Passion finds its linguistic roots in the Latin “passio,” which literally means “suffering.” For much of its history, this suffering was exclusively associated with the passion of one person – Jesus Christ.

But, as for many other words, passion’s meaning changed over time. By the Middle Ages, passion was also being used to refer to the suffering of people other than Christ. And by the Renaissance, the term slowly took on non-negative connotations. Poets like Geoffrey Chaucer began to use the word to describe surging emotions in general, and it was Shakespeare who finally used the term in a more positive light to describe the uncontrollable desire one feels for another person.

The story of the term doesn’t end there, however. It took another couple of centuries for the meaning of passion to extend beyond people to activities or career choices. By the 1970s, phrases like “follow your passion” had begun to emerge; passion-seeking had finally become an important part of the average person’s life.

And the concept has only become more important since then, with Generation X and Millennials even more enthralled by fulfilling their personal passions than their baby-boomer predecessors.

Just like the word “passion,” the biological mechanisms of passion itself have both positive and negative connotations.
That’s because passion is regulated by dopamine, a powerful neurochemical that motivates us to do things. Once released by the brain, dopamine pushes us toward our goals and makes us crave rewards. Dopamine drives passionate people in their pursuits but also motivates drug addicts to satisfy their cravings.

Only the finest of lines exists between the personalities of extremely passionate people and those of drug addicts. That’s because while dopamine motivates us to pursue rewards, the chemical dissipates once we receive them. This, of course, leaves us yearning for more. And, as with addictive drugs, the more dopamine we experience, the higher our tolerance for it becomes. We begin to set our goals higher and place ever-increasing importance on chasing our passions. And we’re never satisfied with the reward; it’s the process of reaching the reward that releases that sweet dopamine.