Even ADHD people are either understimulated or overstimulated (and sometimes both at different points in time). Soft color and textures etc. are ideal for overstimulated ones (aka me). Would not work for my husband, who needs strong colors, comforting clutter, physical contact and studying in coffee shops (gasp!). Other ADHD people I met were similarly divided. I tend to agree with the experts that argue that ADHD is in fact an umbrella diagnosis and there are several different mechanisms at play. And that doesn’t even cover co-morbid conditions like SPD, OCD etc. I know ADHD people that find indoor plants comforting (natural exposure and all that). All I think is dirt, water spots and the possibility of fungal or insect diseases.