Does ADHD Medication Stop Working? Tolerance and Dose Increases

"The medication doesn't work like it did in the first months" is a sentence that gets said often, and right after it comes one word: tolerance.

Yet beneath that sentence there are at least five different possibilities, and tolerance is one of the rarest of them. This article rules out the possibilities one by one. Dose decisions are the doctor's.

First, the matter of expectation

The effect seen in the first weeks is often the most striking one. Something you have struggled with for years suddenly becoming easier leaves a strong impression.

As time passes, that ease turns into the new normal. The point of comparison shifts: you are no longer comparing with the time before the medication, but with the medication's first month.

This is not the effect fading; it is the measuring stick moving. The way to tell the difference is to go back and look at the weeks before the medication. The question "what was I unable to do back then" often puts the picture back in place.

The dose may have stayed low from the start

Treatment generally begins with a low dose and is adjusted gradually. NICE (NG87) and the European consensus statement (Kooij et al., 2019) describe this gradual adjustment as the standard approach.

Sometimes the adjustment is left before it is finished: the first dose works to some extent, the person is satisfied, no check-ups are attended and the dose stays there. The feeling of "it isn't enough" that appears months later is in fact the result of an adjustment that was never completed.

This is not tolerance; it is incomplete titration.

Life may have changed

The medication's effect is fixed, while the load of life varies.

• If the workload has grown, the same dose does not give the same result.
• If sleep debt has grown, attention drops anyway; I wrote about this in the article on sleep.
• A change in weight can change what the dose amounts to in the body.
• A new source of stress adds a load that the medication cannot cover.

A dose increase made without these items being discussed changes the wrong variable.

A co-occurring condition may have worsened

Depression, anxiety, sleep apnea, thyroid problems and iron deficiency all affect attention and energy.

If the medication is not working the way it used to, there may be another picture growing in the background. This is why these things are asked about at a check-up appointment.

I wrote about the relationship between depression and ADHD in a separate article.

How real true tolerance is

Whether tolerance in the clinical sense develops with stimulants is a disputed topic. The World Federation consensus statement (Faraone et al., 2021) reports that efficacy is generally maintained with long-term use.

The approach accepted in practice is this: a diagnosis of "tolerance" is something to be discussed after the other possibilities have been ruled out. First expectation, dose, sleep, load and co-occurring conditions.

The problem with raising the dose on your own

Taking one more from the box you have left is very common, and unwise.

First, side effects depend on the dose: anxiety, palpitations, insomnia and loss of appetite become more pronounced as the dose rises. Second, with a controlled medication the quantity is tracked; I described this framework in the article on the prescription. Third, when the raised dose does not give the expected benefit, you are left with no information, because the change was made without a plan.

A dose increase is not a trial; it is a measurement. For the measurement to be useful, when it was done, how much and by looking at what needs to be written down.

When a dose increase comes up

If the doctor decides on a dose increase, the things to follow are usually these:

• The change in symptoms: which tasks have become easier.
• Side effects: sleep, appetite, anxiety, palpitations.
• Blood pressure and pulse.
• How long the effect lasts: when during the day it starts to fall off.

Writing down these four for two weeks becomes the basis for the decision at the next appointment.

What stays with me

The sentence "tolerance has developed" is in fact often used to close a conversation. Yet the real work is in opening that sentence up.

The useful question I took from this article is this: has the medication changed, or has the load of life? Asking it most often leads to a conversation about sleep and workload before a conversation about dose.

Decisions about dose, medication and duration are things to be made with your doctor. This article is so that you go to that appointment with your hands full.