This theory has now been discredited .
This theory has now been is no longer generally accepted by the scientific community , but endogenous production of neurotoxic tetrahydroisoquinoline derivatives such as norsalsolinol continue to be investigated as possible causes for some conditions such as Parkinson 's disease .
This theory has now been discredited and is no longer generally accepted by the scientific community , but endogenous production of neurotoxic tetrahydroisoquinoline derivatives such as norsalsolinol continue to be investigated as possible causes for some conditions such as Parkinson 's disease .