What is the maximum number of patients an "X" DEA registered physician can treat after a year with approval?

The "X" DEA registration, which is issued to practitioners who are authorized to prescribe medications for the treatment of substance use disorders, specifically under the Drug Addiction Treatment Act (DATA) of 2000, allows a maximum number of patients that a physician can treat. Initially, physicians are permitted to treat up to 30 patients. After one year, they may apply for an increase to a maximum of 100 patients.

However, physicians who have received additional training or meet specific criteria can be approved for a higher patient limit. It is essential to note that under certain conditions, specifically for those physicians who have completed additional training and have been approved by the Drug Enforcement Administration, the limit can be increased significantly, allowing treatment for a maximum of 275 patients per year.

This context explains why the correct answer mentions a maximum of 275 patients, as this is applicable following specific approvals and training enhancements in the treatment of opioid use disorders.