HEBEPHRENIA

[he.be.phre.nia] n [NL, irreg. fr. Gk hebetes young adult (fr. hebe youth) + E -phrenia; fr. the childish behavior which is often found with it] (1883): a form of schizophrenia characterized esp. by incoherence, delusions lacking an underlying theme, and affect that is flat, inappropriate, or silly -- he.be.phre.nic adj or n