What distinguishes Shared Psychotic Disorder from other delusional disorders?

Shared Psychotic Disorder, also known as folie à deux, is characterized by the phenomenon where an individual develops delusions or other psychiatric symptoms that are similar to those of someone with whom they share a close relationship, usually a family member or significant other. This distinguishes it from other delusional disorders, which typically result in a solitary individual presenting with their own unique delusions without influence from another individual.

The essence of Shared Psychotic Disorder lies in the relational dynamic; one person (the primary or predominant individual) has a well-established delusion, and the other person adopts these delusions through their close association, often without having any clear personal psychopathology themselves. This transmission of beliefs occurs in the context of a close relationship, making the shared aspect critical to the diagnosis.

In contrast, hallucinations, bizarre beliefs, and chronic psychotic episodes may be present in various forms of delusional disorders, but they do not capture the essential feature of Shared Psychotic Disorder, which is the acquisition of delusions from another person. Therefore, option B accurately encapsulates the core distinguishing feature of this disorder.