Adult ADHD — which is basically the same as childhood ADHD, just with more responsibilities — can be a career wrecker. More specifically undiagnosed ADHD can wreck careers. If discovered as present, many find ADHD to be manageable. But even with awareness, the presence of a very common ADHD trait must be dealt with on a daily basis.

ADHDers call this Time Blindness.

If you have been enjoying yourself so much that you lost track of time, you have experienced just a hint of what Time Blindness is like for someone with ADHD. Only it doesn’t just happen when you’re having fun or “in the zone.”

It happens when you’re in the shower, and need to leave at a certain time or you will be late for a date.

It happens when you’re talking to someone at work or at a party and have no idea that you’ve been talking so long that they now think you’re a total cad.

It happens when you try to handle your finances, but just can’t seem to get a grip on how to budget your money.

It happens when you have a work project due in two weeks — or worse, six weeks — but don’t start on it until the day before it’s due.

People with ADHD basically have difficulty with what is called Executive Function. This is a set of operations that the brain performs to keep your life moving in an orderly fashion. They include:

Working (short-term) memory
Reasoning
Task flexibility
Problem solving
Planning and execution

While people with ADHD can do these things, there are literally blood flow and oxygen issues in parts of the brain that control them. Neurotransmitter levels are lower. Sometimes, especially when they are tired or bored, the requisite connections just don’t get made.

Time Blindness is really just a casual name for having a shorter Time Horizon — the length of time that we can realistically imagine and work with. For many people, imagining centuries or millennia are intellectually possible. But imagining them in terms of planning and budgeting is just off the charts. For some, that Time Horizon is more like decades, or even just a few years. They can’t “see” beyond that. They know it is there, but it does not feel real. It’s out somewhere in the hazy future. Pairing such a distant future point with the actions needed today to arrive as you want to arrive is unrealistic.

For a person with ADHD, that Time Horizon may only be weeks or even days.

Think of it this way: If you are driving a relatively short distance, such as a few miles away, you can easily imagine what time you need to leave to get there. The further the distance you have to travel, the more you may feel you need to “round up” the time it will take, perhaps adding on some extra time for unforeseen delays. This is especially true if you have never driven the route before.

Now, imagine that you are driving across the entire United States. Your destination is a friend’s house on the opposite coast. Sure, you can do the math and get an idea of how many days it will take to make the drive.

But what if your friend insisted that you tell him exactly what time you will arrive, within a 15-minute window?

That feeling you just got? That’s how a person with ADHD feels when they’re getting ready to go out to dinner. They know they have to be at the restaurant at 7:00. They know that it will take about half an hour to drive there. They know it will take 20 minutes to shower and dress. They know it will take …

And the calculations begin. If they miss any piece of the process — like forgetting that they need to stop for gas — they will be late.

If the appointment a person with ADHD is heading for is something regular, like getting to work in the morning, they may eventually get a plan down and know exactly where they need to be at every stage of their morning routine. Clocks, timers, alarms, and other reminders are crucial.

If they never get this math down on a note, they are chronically tardy. Employers start to characterize them as irresponsible, lazy. And the person with ADHD knows that is what the boss is thinking. It is the same thing that teachers thought. The same thing their former friends thought.

People with ADHD have trouble holding jobs, handling money, and planning anything beyond the reach of their headlights. They are far from lazy, often building a dizzying array of prosthetic aids around them to keep them in sync with the rest of the neurotypical world.

But it never goes away. You just get better at handling it.

Difficulty making it to work or other appointments on time is just one facet of Time Blindness. Budgeting, saving — planning almost anything for the future — is affected.