Ok thank you. What would be considered chronic use? For a clear cut example, if I take 3 mg friday and all anxiety dissapears, I feel sluggish and slightly more sociable on Saturday, but nothing really on Sunday. Would I be able to dose on Saturday, say, 1.5 mg to get that similar effect? I'm just a bit confused as to how the amount remaining in your blood effects the body, and if theres a clear cut difference between being under the influence and feeling the residuals and if so where that line is drawn.
First of all it would be important to know what benzodiazepine you're taking as tricomb mentioned.
The amount remaining in your blood will affect you during chronic usage because the dosage you ingest, will overlap with the dormant benzodiazepine blood levels in your system, creating an additive effect. There's no clear cut line as it occurs in chronic usage, chronic means non-stop, this could be a dosage anywhere within the several half-lives of the select benzodiazepine done continuously over weeks, months, or years. If the drug and it's metabolites have been excreted, then taking the next dosage will not affect the one before. The longer you continue to take benzodiazepines and at a more frequent rate the higher and quicker blood/fat levels you will achieve. Of course the overlap could happen with something as small as two consecutive dosages but certainly nowhere near to the same extent as during chronic dosing.
The residual effects don't really have much of an effect on their own, such as taking diazepam for a week and relying on the residual effects for anxiolysis. The 'residual effects' only work together with the ingested dosage to potentiate it, and the ingested dosage will help maintain the blood/fat levels in chronic usage.
Let me give you an example with diazepam:
Diazepam has a half-life of up to 200 hours, and it's the most famous benzodiazepine for this due its high lipophilicity (long half-life). Lets assume you take the first dosage of 10 milligrams on day 1. On day 2 you take another 10 milligrams. The next day 10 milligrams. You continue taking one dose of 10 milligrams for a week. So by the time you've reached your last dosage on the last day of that week, the dosage you took on the first day of the week hasn't even reached half-life (which means half of that drug has left your system). So when you take your 8th dosage, you have that in addition to all the accumulated blood/fat levels to provide you with a more potent and additive effect. If you decide to skip your eighth dosage, then you will still get limited benefit from the diazepam for a day or two at best (residual effects).
The important thing to note is, just because the half-life of a drug is 200 hours, it doesn't mean that it stays active for that long. This is a whole different discussion but things such as receptor desensitization comes into play which disallows that.
The only clear cut line would be for you to measure benzodiazepine serum levels in chronic dosing, and measure them during intermittent dosing. A vague measurement would be self-assessing the potency of benzodiazepines during intermittent dosing and chronic dosing.