Assalaamu alaikum Nisthar,
Dopamine is a natural hormone you need for your body to function. I got the following from Psychology today:
What is Dopamine?
Dopamine is a neurotransmitter that helps control the
brain's reward and pleasure centers. Dopamine also helps regulate movement and emotional responses, and it enables us not only to see rewards, but to take action to move toward them. Dopamine deficiency results in Parkinson's Disease, and people with low dopamine activity may be more prone to
addiction. The presence of a certain kind of dopamine receptor is also associated with
sensation-seeking people, more commonly known as "risk takers."
Source:
https://www.psychologytoday.com/basics/dopamine
If you didn't have any dopamine, you couldn't move. (smile) And from reading the above, it seems that having less could make you
more prone to addictions. (smile) So it seems to me that it couldn't possibly be the shaitan. (smile) Besides which, the shaitan is described as "smokeless fire". Doesn't sound like a hormone molecule to me...
May Allah, the One Who Knows, Protect us from the whispers that cause doubt.