What's the difference?
 

Between psychotic depression and schizoaffective disorder depressive type?
I'm just being nosey :P

What does google or wiki say?

Schizoaffective normally involves a relatively 'equal' duration of psychotic and affective symptoms and you must have psychotic features without the depression for at least 2 weeks. The delusions/hallucinations may or may not be compatible with mood (mood-congruent).

Psychotic depression, on the other hand, often involves delusions and hallucinations that develop AFTER the onset of depression and are often mood-congruent (e.g. delusions of guilt). Psychotic period must be comparatively shorter than the depressive period.

Differential diagnosis is hard- and there is a great level of fluidity within the diagnoses. I personally view them on a spectrum, with psychotic depression on one end, schizoaffective in the middle and schizophrenia with depressive features on the other end. One can move along the spectrum.

Hope this helps :-)

from the new DSM:

depression with psychotic features = all the symptoms of a major depressive episode with delusions OR hallucinations

schizoaffective disorder (depressive) = Major Depressive Episode, concurrent with symptoms that meet Criterion A for Schizophrenia (criterion A being at least two of: delusions, Hallucinations, Disorganized speech, Catatonia, Negative symptoms, i.e., restricted affect or avolition/asociality)

So yes, it appears they are very similar, but it looks like schizoaffective disorder places more emphasis on the psychosis side of things - if someone's depressed with just hallucinations or delusions they will be diagnosed as depressive with psychotic features. If they have both, or psychotic features in addition to this they will be diagnosed as Schizoaffective.

I could be wrong.. but that's how it appears.

badically psychotic symptoms are present during the depressive episode only when it is psychotic depression.

While schizoeffective the psychotic symptoms are present outwith the mood episode also... plus they can have manic episodes. It is hard to diagnose as there is such an over lap between depression, schizophrenia and bipolar disorder.

DevilGirl pretty has it spot on. Initially I was diagnosed with psychotic depression, then my pdoc at the time realised the voices were worse and more mood was up and down (had quite a few manic phases). That stayed fine until recently I was diagnosed as schizophrenic.

As for treatment: generally it is the same. A antidepressant is prescribed, and if the psychotic symptoms are bad, then one of the antipsychotics are prescribed. If they feel your mood is constantly (or considerably) unstable, then they make prescribe a mood stabliser (such as lithium) but most of the time it is not necessary. Lithium requires you to have regular blood tests, and if the dose is dangerous, can potentially poison you, so docs tend to avoid prescribing it unless strictly necessary.