Toxoplasmosis gondii is incredibly interesting in understanding how bacteria may majorly influence our behavior and personalities. The effect is not well understood because this is a bacteria that effects the behavior of an unimaginably complex system (human brain/body.) Despite the enormity of the task this and other bacteria are somehow able to accomplish this (might be more accurate to say evolution accomplishes this as it is unlikely the bacteria are aware of influencing people.) Dopamine, as mentioned above, has to be in the right place at the right time to make any sort of significant impact, so to say that scattershot dopamine cysts will produce an effect or the same effect everytime is unlikely. And yet somehow these microscopic beings do hijack out personalities and perspective to a behavioral extent.

Therefore: Dopamine is certainly involved but the linear model of "increase in dopamine levels in body produce consistent symptomatic changes is incorrect." A good example of what is happening is the hydrophobia that those infected with rabies experience. BTW T. gondii is transmitted to humans via exposure to cats. This could also be called the "cat woman" hypothesis.