Schizoaffective disorder was originally defined through negative space, meaning that doctors could see a pattern in patients with different diagnoses, and a definition needed to be created to describe that group. That's why doctors haven't settled on a single definition. It's essentially bipolar with schizophrenic features. Or bipolar with full-blown schizophrenia. Saying "schizophrenic features" is the same as the way they used to put it: "borderline schizophrenia". That latter illness is now referred to as borderline personality disorder. So a good working definition of schizoaffective disorder would be bipolar with either schizoprenia or borderline personality disorder — or, to put it another way, psychotic bipolar. Except bipolar can also be unipolar, as someone can be more one side than the other. (I'm fairly unipolar on the depressive side.) What I personally deal with could be described as generalized anxiety, major depression and BPD. Except schizoaffective, more than anything else, is a mood disorder. The other issues are comorbid. If schizophrenics live in delusion and/or hallucination, schizoaffectives live with constant, drastic shifts in mood, and non-stop agitation. (That's another big difference between the two: schizophrenics live *in* their reality, but schizoaffectives live *with* theirs. Our thinking is closer to the surface, our behavior more anti-social.)
There are three groups of people with mental illness. Roughly ten percent of the population deals with mental illness to the degree that they can still function and participate in society, and treats it with therapy and a pill or two. Roughly one percent of the population (the seriously mentally ill) deals with hardcore mental illness that limits or eliminates their ability to function, and treats it with a cocktail of medication and a lifetime of making occasional visits to the psych ward. Life may also include AFC (Adult Foster Care). Roughly a tenth of a percent of the population (the severely mentally ill) deals with crippling mental illness that keeps them under constant care, often in state hospitals. The latter two groups are referred to as "the mentally ill". That means that those who fall into the first group are dealing with mental illness, but not with being mentally ill. Almost by definition, receiving a disability pension is what puts one in that group. People with wealthy families can avoid social security but still be in that category — as, of course, anyone not protected by the safety net. It's just that, for the most part, all the mentally ill are receiving social security.
The signature trait of schizoaffective disorder is that, once it sets in, it doesn't let up for a moment, for the rest of your life. Its moment-to-moment emotional and mental brutality explains why we have the highest suicide rate, and the highest rate of drug and alcohol abuse. Medication is less effective on us than on any other group, and, like any mental illness, there is no cure. Schizoaffective is a barrage of noise combined with a raw emotional self constantly boiling over. We tend to stick close to home, and often lack even the most basic functioning required of an independent adult. Many of us are, in fact, living in AFC or (if they can afford it) assisted living, though the severity of the illness varies. Our abrasive and confusing behavior is our main symptom, at least as far as the public is concerned. Inside ourselves we deal with depression, anxiety, paranoia, other comorbid symptoms such as ADHD or OCD, and sometimes hallucinations. A social visit is probably the best thing you can do for any schizoaffective person you might know.