Amino Acid Tied to Depression in Parkinson's Patients
 (HealthDayNews, 6/21/04)

As reported in the June 21, 2004 edition of the Archives of Neurology, investigators studied 97 Parkinson’s patients, 54 of whom were taking levodopa. The researchers gave the subjects a depression questionnaire, assessed their cognitive and motor skills, and divided them into two groups based on whether they had normal or high blood levels of the amino acid, homocysteine. The scientists found that participants taking levodopa tended to have higher homocysteine concentrations than those not taking the drug and that subjects with high homocysteine levels were more depressed and had worse cognitive functioning. These findings raise the possibility that levodopa may raise homocysteine levels and thereby contribute to cognitive, motor and emotional deterioration.