Invisible Illness Awareness Week is dedicated to the millions of people who struggle with invisible illnesses and disabilities. The week of Sept. 28 - Oct. 4, 2015, is a significant one for this very special group of people.

They are hoping that able-bodied people will listen to what they have to say, and experience a great understanding of what they deal with every day of their lives.

Invisible Illness Awareness Week has been on the calendar since 2002, conceived and created by Lisa Copen, who has suffered from chronic invisible illness for many years. Copen has run a website for those with chronic illnesses called Rest Ministries since 1997.

In 2002, Copen organized her volunteers to help in the running of chat rooms for Invisible Illness Awareness Week. Starting in 2003, speakers made themselves available for a virtual conference. Later there would be Blog Talk Radio podcast conferences.

The first photo campaign was held in 2012. The Invisible Illness Awareness Week that year was spotlighted on the CNN Health webpage. Lisa was a chat guest on their Facebook page.

The 2012 conference for Invisible Illness Awareness Week has been viewed 60,000 times since then.

In 2013, guests presided over discussions on the Facebook page. In 2014, a video virtual conference was held.

Facebook, Pinterest, Tumblr and Twitter have been versatile and fruitful arenas for those with invisible illnesses.

The theme for the 2015 campaign is "Invisible Fight." And that is exactly what this is all about.

Here are just a few of the invisible illnesses and disabilities experienced by almost 50 percent of Americans, according to Disabled-world.com: ADHD, allergies, asthma, autism, brain injuries, ME/CFS, celiac disease, Crohn's disease, depression, diabetes, epilepsy, fibromyalgia, IBS, lupus ...

Trust me, it's a very long list and I don't have room for it here.

Illness and disability can often bring with them misunderstanding and dismissal from others.

It's simple, really. An invisible illness or disability is not readily evident to other people.