Is it possible that low serotonin in a child cause him to be slow minded, have obsessions, inferiority complex and advanced or?

Not clear: There are presently hypotheses that genetic polymorphisms associated with differential concentrations of neurotransmitters can predispose to certain personality traits and mental disorders. It is not thought at this point that the presence of individual alleles is deterministic. In other words, there is a lot of interaction between genes and environment including epigenetics and unknown variables.