Answer:
It is likely that Jeremy’s basal nuclei is producing less dopamine than it needs to.
Explanation:
Parkinson's disease is caused by less production of neurotransmitter dopamine from basal nuclei present in the cerebrum of the brain. Lower levels of dopamine have caused Jeremy's mental health. He needs to smoke more than earlier to fight depression caused by lower dopamine levels.
Dopamine imbalance would also affect his balance and coordination of muscles. He would not be able to perform the routine tasks by himself.