Question: what is the most subtle brain disease

Daniel Mietchen answered on 24 Jun 2010:

Well, subtle in what respect? Many psychiatric disorders would probably qualify in the sense that their initial stages (e.g. what is called the prodromal phase in schizophrenia and related conditions) go along with only very subtle changes in behaviour. We work on picking up the corresponding changes in brain structure in order to facilitate diagnoses in those early periods because that is when help has the greatest effect. To be more concrete, schizophrenia is more subtle than Alzheimer’s in terms of changes in brain structure, and addiction generally more subtle still (though this varies with kind).

Another kind of subtlety may be invoked in cases like stroke, where blood flow is blocked for some reason for a short period of time. If the affected blood vessel is large, the effects on brain function (nad possibly also structure) may be very devastating. If, however, only very small vessels are involved, then the person may not even notice the event.