Anxiety psychiatric diseases associated with

Although L-dopa can increase dopamine levels in the brain, its effectiveness decreases across time, such that larger and more frequent doses are required for it to be effective. In addition, after only 2-5 years of L-dopa treatment, its duration of effect is reduced. Chronic administration of L-dopa has been reported to produce psychiatric symptoms, such as paranoia, mania, anxiety, depression, hallucinations as well as increased incidence of insomnia and nightmares (92). It is not clear whether these symptoms are associated with chronic L-dopa therapy or disease course, since the two are temporally related (94). Chronic L-dopa therapy may also produce a state where patients response to administration fluctuates, such that they experience an on/off phenomena of L-dopa s effects. Additional symptoms of dyskinesias, e.g., involuntary twisting and writhing, are associated with this on/off phenomenon. Consequently, treatment with L-dopa is typically delayed until other treatments are no longer effective. 

---