In the Gralnick classification of 1942 the term folie à deux is classically divided into four basic subtypes: folie imposée, folie communiquée, folie simultannée and folie induite. This last one refers to the addiction of new delusions in a previous psychotic patient, under the influence of another patient. We report a case of folie induite that occurred between mother and son, both diagnosed previously with psychotic disorders (delusional disorder and schizophrenia, respectively), who started to share persecutory and sexual delusions. Cases of folie à deux generally correspond to the induced psychotic disorder in the DSM-IV-TR or the induced delusional disorder in the ICD-10. However, our patient do not meet neither diagnosis, since, in both, it is necessary that the induced delusional patient do not have any previous psychotic disorder. We think that our report underscores the insufficiency of the modern classifications in this area. Cases of folie induite may require a management different from those used in other cases of shared or non-shared psychosis. We suggest that modern criteria should be revised to include cases such as the present one.
Folie à deux; induced psychotic disorder; induced delusional disorder; schizophrenia