People with ADHD are often "time blind," which means they are unaware of the passage of time. As a result, they frequently find it difficult to manage their time properly.

It is widely known that time blindness is definitely a symptom of ADHD. However, more research is needed to discover the root cause of it.

One obvious contributor to time blindness is hyperfocus, the "in the zone" mode that many believe to be an ADHD superpower. One disadvantage that it has, however, is that when the ADHD brain is hyperfocused it loses all sense of time. Someone with ADHD could be hyperfocusing on an art project and not realize that they have not only forgotten to eat lunch, but they are now late for their 5:30 dinner reservation they planned weeks ago.

Time blindness doesn't only affect our immediate perception of time though. It also shortens our "time horizon". A time horizon is the point in the future at which things cease to feel real and begin to feel imaginary. It is the temporal frame in which we can realistically envision and work.

For most neurotypical people, they are able to plan months, and sometimes years into the future because events in the distant future seem real and tangible. For people with ADHD, however, that timeframe is vastly reduced, sometimes down to mere weeks, or even days. This can cause major issues when trying to set goals for the future, or meet deadlines. Oftentimes, if a large project is assigned to someone with ADHD without a deadline, that project will be ignored (especially if seems boring) until a hard date is set. This is because having no date automatically puts it way out in the future and not tangible. However, if a date it put on the project, especially one that is within a few weeks, that project will suddenly become something tangible within the ADHD brain's time horizon. Thus, it will get put high on the priority list. Many people with ADHD tend to develop coping mechanisms to compensate for their shortened time horizon, becoming very good and working efficiently in a time crunch.

One unusual effect of time blindness, is that it seems to have the opposite effect for many people with ADHD when it comes to events in the past. To a person with ADHD, an event that happened years in the past could seem as if it just happened yesterday. This effect is usually tied to the emotional dysregulation part of ADHD as the events are usually tied to some emotion they were feeling at the time. A sad event such as a death, or a difficult breakup, could suddenly come up and the person would feel the same as if it had just happened. This makes it very difficult for many people with ADHD to move on from the past.