ABSTRACT
Delusions and misidentification can be defined as false or incorrect beliefs in perception and experience. They are classified as polythematic, typically observed in psychiatric patients and affecting different areas and the whole behaviour, and monothematic, limited to a single topic and often a result of a brain damage, focal or diffuse, as in some forms of dementia.
In this final chapter we describe the main forms of monothematic delusions, such as Capgras Syndrome, where the affected person can recognize well-known persons as familiar, but deny their identity, waiving them as doubles or impostors.
In other cases the affected person denies his/her neurological deficit and can consider the paretic limb as alien.
A tentative explanation of the different forms of monothematic delusions is offered, pointing to a process of disconnection between the neurological site leading to the specific deficit and frontal lobes whose task is to assess the reliability of the content processed by the affected neurological impairment.
