Persistent delusional disorder

• Systematised, fixed delusions are the major or only feature

Schizotypal disorder

• A disorder characterised by eccentric behaviour and anomalies of thinking and affect which resemble those seen in SZ, though no definite and characteristic SZ anomalies occur at any stage
• The symptoms may include a cold or inappropriate affect, anhedonia, odd or eccentric behaviour, a tendency to social withdrawal, paranoid or bizarre ideas not amounting to true delusions, obsessive episodes which intense illusions, auditory or other hallucinations and delusion-like ideas, usually occurring without external provocation

Acute and transient psychotic disorder

• SZ-like symptoms, lasting one month

Increased delusional disorder

• Folie a deux, folie a pusiers

Schizoaffective disorder

• Episodic disorders in which both affective and SZ symptoms are prominent but which do not justify a diagnosis of either SZ or depressive or manic episodes