L-tryptophan administration in L-dopa-induced hallucinations in elderly Parkinsonian patients

L-tryptophan (L-T) was added at a dose of 150-450 mg daily to eight Parkinsonian patients who developed visual hallucinations with paranoidal features under L-dopa (L-D) treatment (112.5-75 mg daily) in combination with alpha-methyldopa hydrazine (12.5-75 mg daily). In six patients L-T ameliorated the symptomatology by arresting the visual paranoidal hallucinations or diminishing their frequency and relieving the psychomotor agitation. As a 'side effect', L-T produced new 'pleasurable', 'LSD-like' visual images in three patients. In two patients, in whom L-T did not affect the mental disturbances, amelioration was obtained only by phenothiazines. Theoretical considerations on the role of dopamine in the genesis of visual hallucinations and mental disturbances emphasizes the benefit of L-T administration in this 'organomental' syndrome.