MCDD: a subgroup of PDD-NOS or a psychotic disorder?

Background:  MCDD in childhood is possibly a forerunner of schizophrenia in adulthood. Children with MCDD suffer from thought disorders, affect regulation problems and impairments in social communication. MCDD is currently not a DSM-IV classification and these children are often classified under PDD-NOS, because of their social difficulties. Another possibility would be to classify this concept under the psychotic disorders, but this would implicate a different approach to treatment and prognosis. Previous studies have shown that MCDD differs from autism but it has not yet been studied whether MCDD differs from PDD-NOS.

Objectives: The aim of this study therefore was to assess whether MCDD can be delineated from PDD-NOS.

Methods: MCDD children (n = 25, 6-12 years of age) were compared to children with PDD-NOS (n = 86) on the dimensions of (psychotic) thought problems, co-morbid psychiatric disorders and social contact problems.

Results:  MCDD was associated with psychotic thought problems, anxiety and disruptive behavior, whereas PDD-NOS was associated with impaired social contact.

Conclusions: MCDD can be delineated from PDD-NOS and it can be questioned whether the current PDD-NOS classification is the appropriate one in all children with MCDD, and whether the overlap with psychotic disorders, or even anxiety or disruptive behavior disorders should not be emphasized more.