The nature and structure of febrile onset psychosis, primarily malaria, in the Sudan were investigated. At least a third of the patients exhibited one or more of the following: excitement, aggressiveness, sleep disturbance, auditory hallucinations, visual hallucinations, paranoid delusional, disorganized thinking, and disorientation. Other notable symptoms were depression, not eating, mutism, and catatoniFactor analysis revealed a schizophreniform deterioration factor, a schizophrenia versus mania factor, a depression factor, a toxic psychosis factor, and an aggression factor. The diagnostic implications for the diversity of symptomatology in febrile onset psychosis were discussed.