Hey there. I'm certainly not schizophrenic but think I can explain this.

Dopamine isn't simply a motivator. Motivation is a made up idea.

Dopamine creates understandings in our environment and information. It creates meaning.

Not even these words would matter to you if it wasn't important to you. We get dopamine and our relationship with it from lots of things and it begins at childhood and the stimulus we experienced while also being genetic. Dopamine creates a moment of understanding or a "click". When people say something "clicks", it's because dopamine assisted in forming a new memory which gets used later to understand the things around them.

Then we have behavior. Impulsive, compulsive or premeditated.

Dopamine is the guidance system for decision making. Which is what we often refer to as "motivation" when simply put, anyone making decisions appears "motivated". That's not really a good way of looking at it.

You're not motivated to get out of the way of a car, nor are you incentivized. In fact, it's probably involuntary. You just know you have to, or else you die. That's a pattern you are able to put together because of dopamine. That's a really basic and frankly, not a very good example but I hope you get what I mean.

Schizophrenics do what they do because they feel like it makes sense, like there is pressure to, or it may even be planned and orchestrated and will make complete sense to them. You'll notice what I'm describing sounds exactly like how you make your decisions and how you get your "motivation". They do it because they feel like it's meant to be done. They've been learning different information because of their imbalance and that's going to determine what kind of action they take.

Essentially, their brains are taking things that aren't meaningful, creating meaning out of it, which results in action - good or bad.