When most people talk to me about problems with focus, what they usually mean is: I can't force myself to keep doing this uninteresting task. Maybe it's building an Excel financial model or writing a product design spec. It's boring, difficult, or both. And, guess what, it can cause real physical discomfort (or psychic unease) that eases when you switch tasks and “focus” on something else. When talking about focus, I often use an analogy I learned during residency. There are really two types of focus: spotlight and floodlight. Spotlight is easy enough to understand. There is a specific, definite thing that needs to get done, and all your mental energy is beamed onto that task. A proposed budget for next year is due by 9 a.m. tomorrow, and you need to put it together and send it out. These can be stressful necessities of work life but mostly require a butt-in-seat grind on known data.

Floodlight attention is what you need to solve problems creatively: explore a wide set of options, evaluate outcomes with incomplete information, and make a decision. It can require quiet, sustained imaginative attention or detailed scenario planning and can be uncomfortable, though it's rarely called “boring.”

Now, where do stimulants fit into this story? They are potently dopaminergic -- Adderall particularly so -- and in our brains dopamine is a salience signal. That is, dopamine spikes tell us when a given stimulus is worth paying attention to (think survival or reproduction).

Dopamine has different effects in different brain regions, and our circuitry is often clever enough to evoke the right effect for the right stimulus. Psychostimulants are nonspecific dopaminergic enhancers: they increase dopamine signaling throughout the brain for extended periods (~12 hrs for Vyvanse). This makes whatever is in front of us (e.g., expense reports) feel artificially important. They also increase endurance and can cause euphoria unrelated to the pleasurableness of the activity. They turn up the spotlight. “OK, great,” you might be thinking, “I’ll get that PowerPoint done lickety-split, then get back to the more creative problem-solving that is my real value add at work.” Not so fast. The floodlight doesn't have an off switch. Published data consistently show stimulants help people grind through tedious tasks (not just those with ADHD -- and for neither group as much as widely claimed) but do not help, and can harm, creative “floodlight” thinking.

If “focus” to you means robotically completing tasks you find mind-numbing, yes, amphetamines will probably help. At the very least, they will make you feel you are “getting more done.” If the floodlight/spotlight analogy doesn't hit home, as it doesn't for some of my more Dexedrine-determined patients, I try one more analogy from the wonderful Carlat Report: stimulants are like hearing aids for our minds. You could put in hearing aids right now and hear louder than before; that’s not proof you have a hearing impairment. They are boosting the normal signal. If anything, focusing more when your focus is boosted is a sign your brain responds appropriately to a dopaminergic signal -- not that you have an organic brain disorder or a psychiatric diagnosis.

There are people for whom amphetamines slow them down, quiet the noise, and make an overtly dysfunctional system appear to normalize and relieve impairment. I still prescribe stimulants daily for folks where the benefits clearly outweigh the costs. But there are very real costs, and for the average person -- one of the 25% of adults who think they have ADHD -- the meager benefits are not worth them.