Acturial methods are used to study the correlation between the initial condition and early therapeutic results, and the present condition of 164 parkinsonian patients treated with L. dopa for 4 to 8 years. There is an ineluctable deterioration in motility. There is a lower risk in patients who are autonomous and only slightly akinetic at the beginning of treatment. Intellectual deterioration is seen in some patients only. The risk factors are: males, the clinical forms of Parkinson's disease in which tremor is not predominant, onset of the disease before 60 years of age, and depression and transitory psychotic disorders during the first year of treatment. This deterioration appears 3 to 5 years after starting dopatherapy, which could be the cause. Life expectancy is still reduced by the disease at the present time. It is longer in patients in whom the disease started with isolated tremors, absence of Babinski's sign, and no loss of autonomy, and those in whom a good initial therapeutic result was obtained.