Something tells me this is either a) really obvious or b) is not really known. But I was wondering...

What factors affect the necessary dosage for someone, and which ones affect the necessary dosage the most? I say this because I think my ADD inattentivness is "mild", compared to others diagnosed earlier in life or those who may be more inattentive to me. Is it just how "ADD" someone is, or does it depend on things like body weight, metabolism, maybe even prior drug usage? I currently take 36mg concerta and 15mg Ritalin in the afternoon for rebound, and weigh 190 pounds. I don't know if I sound dumb in this post, bu t maybe it is a valid question...:confused:

It is correlated with weight, but that said, there are so many variables that it's more art than science when determining the correct dose.

b) not really known. (for the most part)

The weight thing is a fairly old method of working out dosage if I remember right. I think they did some studies on this and figured out it wasn't a huge factor in the dose people need to get the therapeutic effects.

I personally think severity of ADD comes into it. If you've only got mild inattentive you may not need as much as a severe hyperactive.

It's probably got a lot to do with each individuals brain chemistry IMO. There's still lots of unknowns when dealing with the brain, new things are being discovered all the time.

Here's a post I made a while ago that relates: Keep in mind this is very unscientific :) and extremely simplified.


I was talking to my psychiatrist the other day and he was telling me about how drugs get metabolized. Was pretty interesting and apparently there's tests starting to become affordable that can show what kind of drugs get metabolized fast or slow in a certain person. I think in the future drugs will be personalized and made specifically for each person...should be excellent :) No worrying about dose.

Here's is a quick example on how stimulants get metabolized, this is my interpretation of what my psychiatrist told me:

Lets say everyone has these things called 'keys' in their bodies and they look like this: ~ Picture them sitting in your tummy waiting for your medication to be ingested.

There's different keys for different substances but we're talking about the 'stimulant' one here.

When you swallow your tablet/s in the morning the key or keys get working on the medication and start trying to 'unlock' the drug so your brain can start using it.


Lets say most people have two 'keys' and it's considered the normal/average type of metabolization..these people are what the recommended doses are based on.

But some people are different - they might have one key ~. This means they can't 'unlock' the medication as well as the average people and thus they need a higher dose to get the same effect.


Other people have 3 keys ~~~ and this means they unlock more of the medication in each dose than both the other types. They need a much smaller dose than average.

So, for example:
~ = needs much higher doses (this is prob. the one you are matt)
~~= average. need normal dose (this is me)
~~~= needs smaller dose. (this might be someone who only needs 2.5mg of dex twice a day)
~~~~= needs much smaller dose. these guys are the ones who often overdose on the average sized doses. hypersensitive


I hope you made some sense out of that. It's not exact science but I think different metabolization levels in different people play a big part in what dose they might require.

I'm sure we'll start to learn more about how this stuff exactly works as time goes on. So much to be discovered - exciting :)

Ozchris got it right IMO with the brain chemistry and also how each of us metabolizes stimulants or medications in general.

The brain is a very complex organ and everyone is unique. That's why it's imperative to start low and go slow. And I believe equally important to have a doctor who knows their stuff and isn't afraid to work with the patient to find the optimal dose.

The bottom line is too low a dose feels like normal unmedicated self or maybe just a slight benefit; too much, for me, I just felt drugged, unable to focus, overall uncomfortable; but the right dose I was able to be calm, focus like a "normal" person, and able to carry on a conversation as well as listen.

If you have not read the sticky on titrating I would recommend it. It's located in the medication section. Good luck

It's more about drug metabolism than weight or severity of ADD. (I specifically asked my doctor today if it had anything to do with severity.)

Definitely agree with watts that you should start low and go slow. I started at the lowest dose possible and increased every 2-3 weeks. It takes time for your body to adjust. I know patience is hard (I actually called my doc the first week and told him that I quit), but if it feels right, then X-amount of medication is just a number.