Multisystem Developmental Disorder

Background
Multisystem Developmental Disorder, also known as MSDD, is a term coined by Dr. Stanley Greenspan to diagnose children under the age of 3 who exhibit signs of impaired communication as in autism, but with strong emotional attachments atypical of autism. Multisystem Developmental Disorder should not be confused with multiplex developmental disorder (MDD).

MSDD is not listed in DSM-IV or ICD-10, but rather is described in the DC:0-3 diagnostic manual, a manual intended to supplement the standard manuals when diagnosing infants and children under the age of three. DC:0-3 (1994) was published by Zero to Three (ISBN 0-943657-32-6) and is currently under revision.

Though MSDD appears very similar to disorders on the autism spectrum, it is thought to be a secondary impairment, in which difficulties in communicating and relating, characteristic of autism, are in fact a secondary result of motor and sensory processing difficulties. It is thought to be related to sensory integration disorder. MSDD presents as milder than pervasive developmental disorders: children with MSDD tend to respond better to treatment, are less likely to have severe delays in mental ability, and are less likely to have severe rituals or repetitive behaviors. But the differences are very slight, and some would argue that they are in the eyes of the observer. Parents should be aware that the same child, diagnosed by a different practitioner, might very well receive the diagnosis PDD or PDD-NOS.

Little is known about the long term outcomes of children diagnosed with MSDD, though generally their prognosis is considered to be better than most children diagnosed with PDD, given adequate treatment.

As with PDD-NOS, some clinicians use MSDD as a "temporary" diagnosis for children under the age of 3, when for whatever reason there is a reluctance to diagnose autism or PDD. There are several justifications for this: very young children have limited social interaction and communication skills to begin with, therefore it can be tricky to diagnose milder cases in toddlerhood. However, some parents view the MSDD label as no more than a euphemism for autistic spectrum disorders, and one that makes it more difficult for parents to understand the importance of early intervention and treatment and to receive fincancial aid for such intervention.

Treatment for MSDD is similar to treatment for PDD, with more focus on sensory integration. Speech and language therapy, occupational therapy and behavioral therapy all have their benefits. Given that the practitioners who diagnose MSDD in the first place are those who are influenced by Greenspan, they are probably more likely to recommend Greenspan's favored "floortime" treatment.