Communication deviance (CD), forms of communication that are not bizarrely thought disordered but are hard to follow and that make difficult the consensual sharing of attention and meaning, has been hypothesized as a nonspecific contributor of rearing parents to psychopathology of offspring, including schizophrenia. This hypothesis, or an alternative of genetic transmission, would gain plausibility if CD has long-term stability. CD was evaluated, using tape-recorded and reliably scored Rorschachs in 158 Finnish adoptees, and retested after a median interval of 11 years. Adolescent CD was not stably correlated with follow-up CD. However, initial CD at a mean age of 32 and follow-up CD were significantly correlated. Gender, genetic risk for schizophrenia, and DSM-III-R (American Psychiatric Association, 1987) psychiatric diagnoses had no effect on adult CD stability. CD appears to be a stable, traitlike feature of adult but not adolescent functioning.