Thanks for starting your own thread, c130herc.
Smoking marijuana
can make a difference in whether you are granted Top Secret clearance, but drug use is only one factor looked at when determining who gets security clearance.
The clearances issued by the Department of Defense are Confidential, Secret, and Top Secret. To have been issued Secret clearance already, the DoD investigated your past seven years, your written reports and your records, verified all of the information, and determined, after examining all of the information gathered on you, that you were eligible to have access to Secret classified information. In order to be issued Top Secret clearance, the DoD will do
another investigation, reviewing your last
ten years. A comparison will be made between the information gathered originally and the new information - to check for changes, omissions, etc.
What will be looked at with your marijuana use is how recent the drug involvement was and whether it was an isolated event. If a seven year investigation showed only minor drug use early on, for instance (especially if it occurred when you were young and stupid), and no recurrence during those seven years, and there were no other concerns with your record, you would probably be issued Secret security clearance. If, however, a ten year review shows this early use of marijuana and, in addition, your more recent use of marijuana, the earlier use of marijuana takes on greater significance. It shows a recurrence.
What also matters in obtaining securtiy clearance is how honest you are in reporting the drug use (or anything else that may be questionable in your past), and the circumstances surrounding the use.
I obviously cannot tell you if you have jeopardized any chance of being issued a Top Secret security clearance because of your use of drugs while having Secret security clearance. As I said, drug use is only one of many things considered when you are investigated. How honest you are about the use is an important factor, however, from everything I have read and researched on security clearances, and you would not want investigators to discover on their own, for instance, that you were once arrested for marijuana use. The reporting of it should be made by you, voluntarily, before it is discovered by investigators.
You should check out any information provided here, by the way, before relying on it 100%. I am not an attorney, and I am not an expert on security clearances (although I am certainly becoming one rapidly
).