I worked in the field of disability arts/arts and disability from around 1996 to 2008 and was part of the original Disability Arts Online team, during which time I came to terms with my own hidden impairments, which are always present, come and go in intensity, and are probably connected in ways I have yet to fathom.
This is an incurable but treatable form of Leukaemia or blood cancer where my body produces too many Lymphocytes (kind of white blood cell) that aren't properly formed. I was diagnosed in 2012, and am currently in stage A which needs no treatment. Symptoms come and go, but are mainly: extreme tiredness, shortness of breath, exhaustion and irregular body temperature. You can read more about CLL on the Macmillan website. If you have CLL, FYI at diagnosis I was FISH chromosome deletion 13q14 in 49% of cells, rGHy2.05 90% homology to germline.
Now somewhat eclipsed by the CLL, this is like a permanent 'post-viral fatigue', which I've had since around 1991-2 with no real change: muscle aches, tiredness, low energy, memory loss and concentration voids. Sometimes gravity feels stronger, stairs steeper. I get mentally fuzzy or overloaded and need to rest or work in isolation, or else find it hard to concentrate without feeling extremely stressed. I sometimes forget important things. Most people notice nothing, because I've become expert at managing my limited resources - I only ask if I want to walk slower or rest, and don't go out when I feel drained. Adreneline gets me by at other times, but I pay the price afterwards. I had lots of tests which came to very little, but a student doctor tentatively recognised the original virus as Parvo, the human version of the canine disease, which (I surmise) caused a chronic disruption of my stress-weakened immune system (sometimes, I even dream I'm a dog). In late 2008 I was treated for a vitamin D deficiency, which was exaggerated the symptoms severely (I was lactose-intolerant and using soya milk, so changed my diet - goat's milk/cheese/yoghurt - and now feel better, but the underlying fatigue remains). Friends and a former partner with chronic fatigue have been really helpful. The remarkable Reciprocality (philosophical site on programming and culture) has some interesting ideas about the high incidence of both CFS and ADD (Attention Deficit Disorder) in programmers (Ted Nelson, who envisioned the hyperlink, has lived with ADD and even has trouble maintaining his own computers); and about contributory factors in CFS. CFS causes are still under research, but recent findings (New Scientist No2241 3/6/2000) suggest causes in a dis-synchrony between the usually harmonised 24-hour sleep/wake signals emitted by temperature and hormonal cycles. Other more recent research is pointing to a deficiency in Choline, which I don't yet quite understand. Like the immune system, it's an issue of some complexity.
In 1990, when I first realised I needed help to maintain a coherent personality (as I then saw it), I avoided Public Health Service therapy and psychoactive drugs (having watched friends go through the process), using instead a series of counsellors, initially via a free public service. The first committed suicide (nothing to do with me, I was assured). The second was a real treasure (with a slight alchohol problem) and tolerated me sitting in almost complete silence (or asleep) for two of the four years I spent with him. He also understood my homespun spirituality. The third went through a marriage break-up (what is it with counsellors?) which I irrationally used as a reason to stop counselling. But through their continuing support I learned to live with my smörgasbord of past and present experiences, including socialphobia, insomnia, obsession-compulsion (symmetry, food, collecting and geometrical perfectionism), and unusual or extreme subjective states, including out-of-body experiences, extreme lucidity and its opposite, for which there is no name, although 'melancholy' comes close. You can read some poetry about melancholy (older but up here since 2000) - thoughtful not depressing, which is what melancholy is actually about. Despite all this, I'm often pretty content and focussed, which contradicts one of the common misconceptions about impairments.
I've arranged some of the natural objects I collect on a page of small things (new window) that gives a personal account of the impact of these mental states on my life. Why go against web access guidelines by opening things in separate windows? I suppose I like the idea of personal stuff living on self-contained web 'islands'. Anyway, if you've got this far you have to be interested enough.