A Dopa-medication leads sometimes in Parkinsonian patients to a psychosis. 2. The diminished capacity of striatal dopaminergic neurons to store DA leads to a storage of DA in serotoninergic or noradrenergic neurons. 3. Extrastriatal noradrenergic and/or serotoninergic neurons are involved. 4. Dopaminergic receptors of the striatium are not involved because of a lack of kinetic response after L-Dopa application in Parkinsonian patients with akinetic crises. 5. Extrastriatal dopaminergic receptors of DA as "false transmitter" at serotoninergic receptors seem to be responsible for the production of psychotic symptoms, whereas noradrenaline is not responsible. Psychotic symptoms can be imagined to be triggered by a contact of a transmitter to a nonspecific receptor.
