Negative polarity - why?

[Natalia Connolly]

Dear cTAKES Experts,

    I have a piece of free text that includes a diagnosis in a stand-alone
sentence, like this:

" - Unspecified pervasive developmental disorder, current or active state -
"

     For some reason cTAKES seems to think the polarity of this statement
is negative:

  <org.apache.ctakes.assertion.medfacts.types.Concept _indexed="1"
_id="18158" _ref_sofa="3" begin="936" end="980" conceptType="PROBLEM"
conceptText="Unspecified pervasive developmental disorder" externalId="0"
originalEntityExternalId="8563"/>

 <org.apache.ctakes.typesystem.type.textsem.DiseaseDisorderMention
_indexed="1" _id="8563" _ref_sofa="3" begin="936" end="980" id="40"
_ref_ontologyConceptArr="8556" typeID="2" segmentID="SIMPLE_SEGMENT"
discoveryTechnique="1" confidence="1.0" *polarity="-1"* uncertainty="0"
conditional="false" generic="false" subject="patient" historyOf="0"/>

     Why is that??  Can it be the hyphens?

     Thanks for any insight,

     Natalia Connolly