As a follow-up, I’ll clarify that aphantasia isn’t directly related to any mental illness to my knowledge. I’ve had it as long as I can remember. It’s not a direct symptom or result of illness and is normally congenital, although it can be acquired through brain trauma like a stroke. It’s believed to be present in roughly 2-3 percent of the population. I learned of it when I heard of an even rarer cognitive difference where some people lack an inner monologue. The term was coined in the late 1800’s, but resurfaced in 2015 and onward with renewed interest and published studies on the phenomenon.
Until these studies were popularized by social media, most people with aphantasia were unaware of their differences. Some work in highly visual fields like media and art, including one of the founders of Pixar and a co-creator of the web browser—Firefox. Generally I feel we have a tendency to think of ourselves as “normal” and similarly give others the benefit of the doubt in most cases. For example, I was unaware that my father also had aphantasia until I described the condition to my mother, who’s a visual artist.
If you want to learn more, there are many online articles, personal accounts and blogs and vlogs about the subject. A question commonly asked is whether people with aphantasia dream in pictures, and most (myself included) do, but some don’t. Despite my talk of compensations I make for my lack of visual imagination, I wasn’t conscious of these preferences until I became aware of the condition less than a year ago.