Table 2.

Sketch of syndromal diagnostic criteria for schizophrenia versus psychotic disorder.

Schizophrenia spectrum	Psychotic disorder spectrum
Subclinical phase	- Syndrome characterized by acute psychotic symptoms—hallucinations or delusions—not preceded by over a year of cognitive decline and/or negative symptoms.
- Presence of subtle, persistent cognitive decline starting in infancy and early adulthood	- Can be characterized by disorganized speech or behavior, if no previous progressive impairment is observed
- Unobtrusive progression of negative symptoms starting in infancy and early adulthood	- Include: delusional disorder, cycloid psychosis (that would cover some types of schizophreniform disorders, and schizophrenias with full recovery and no cognitive decline or negative symptom progression before the first episode psychosis), brief psychotic episode.
Prodromal phase - Unspecific depressive and/or anxiety symptoms, starting some years after the subclinical phase, and lasting 1 or 2 years	- Exclude: mood disorders with psychotic features, substance-induced psychotic episode, psychotic symptoms due to a somatic condition.
Psychotic phase - Irruption of psychotic symptoms following the prodromal phase May be absent in Schizophrenia Simplex
– Exclude: neurodevelopmental disorders, neurocognitive disorders, and substance use disorders, as primary cause of early cognitive decline; psychotic disorders and mood disorders, due to different syndromal presentation.