These slides outline the conundrum of treating schizophrenia – in the ‘normal’ brain the levels of dopamine in the mesolimbic and mesocortical pathways are in balance.[Stahl, 2013] However, in the brain of a patient with schizophrenia, the levels are out of balance, with levels in the mesolimbic pathway too high and levels in the mesocortical pathway too low.[Stahl, 2013]

Reference:
Stahl SM. Stahl’s Essential Psychopharmacology. Neuroscientific Basis and Practical Applications. Fourth Edition. © Cambridge University Press, 2013.