Hi @realtreebivvy. It is interesting you mention IQ and that many people including experts tend to dislike psychodynamic theory and much of Freud's work. I personally love his process.
So about IQ You are right that those with low IQ tend to have a violent streak. However these theories, can be used with all IQ's as it is meant only to help understand where one comes from.. their experiences and how they work and respond to situations.
So Freud believed we are born with a primitive principle that can end up controlling us.. If this state, the id, does control us then it is possible to have a low IQ. Because the id is all about immediate gratification it can stunt our emotional growth and that can become a ripple effect, impacting the IQ. However if all three states are at play in our life, mind etc one can grow healthy and have an IQ that is reachable by that person..
He also believed that how we are brought up impacts what principles (Id, ego and superego) are effected, therefor creating our personality with healthy semi healthy or not healthy and all the in between.
I believe that if each theory is used correctly with a existential process each theory can benefit an individual
RE: Theories Of Personality: Introduction (Part1)