The administrative review proceeding began with the issuance of a Notification Letter to the Individual. See 10 C.F.R. ' 710.21. The letter informed the Individual that information in the possession of the DOE created a substantial doubt concerning his eligibility for a security clearance. Specifically, the Local Security Office (LSO) stated that the Individual had: (1) been diagnosed by a psychiatrist as suffering from cannabis abuse, an illness or mental condition of a nature which causes, or may cause, a significant defect in judgment or reliability; (2) used marijuana and therefore engaged in illegal drug use; and (3) engaged in unusual conduct which brought his honesty, trustworthiness, and reliability into question by providing inaccurate information to DOE security officials.