AbstractWe reviewed the records of 358 patients with various forms of focal, segmental, and generalized dystonia who had received pharmacotherapy in a systematic order, beginning with anticholinergics. If no benefit was encountered, we then tested clonazepam, baclofen, and other agents sequentially. In each situation the dosage was gradually increased until benefit or troublesome adverse effects were encountered. In this manner we obtained data on the percentage of patients who showed moderate to marked benefit. Anticholinergics were the most beneficial agent, confirming previous reports. Statistical analysis of this response revealed that benefit from anticholinergics was most likely if treatment was begun within 5 years after the onset of dystonia. From this analysis, it appears that delaying treatment beyond 5 years is likely to result in an unsatisfactory response.