Objective: Here we report the case of a schizoaffective psychosis in a female carrier of fragile-X (CGG sequence > 200).
Clinical picture: The patient presented with symptoms of psychosis (hallucinations, delusions and disorganised thinking) and mania, preceded by decline in intellectual and social functioning.
Treatment and outcome: Initial treatment with antipsychotic drugs alone or in combination with sodium valproate was only partially effective, but the addition of lithium resulted in a complete remission.
Conclusions: One year later the patient presented predominantly with deficit symptoms and profound deficits in memory and executive functions. It is likely that the intellectual deterioration around the time of puberty associated with fragile-X increased her vulnerability to a schizoaffective disorder and eventually to poor functioning.