Because of missing diagnostic biomarkers, schizophrenia spectrum disorders still pose a
diagnostic challenge. In daily clinical practice, especially when deciding admission to inpatient
treatment it is not uncommon to reserve the diagnosis of SZ for severe cases presenting with
flamboyant psychotic symptoms such as bizarre delusions or first-rank symptoms, reflecting
uncertainty in distinguishing SZ from SAD. However, patients with SAD might exhibit more
severe depressive and negative symptoms, lower age of onset , less cognitive disabilities
, and better social functioning when compared to SZ individuals. Correspondingly,
there is some evidence that patients with SAD have better clinical outcome than those with SZ
. It is fair to assume that these reflect the episodic character of SAD compared to SZ. Still,
the diagnostic stability of SAD is poor and the diagnosis at the first admission is often not
definitive .