Patients with schizophrenia generally perform worse than control subjects on all cognitive domains, and particularly in memory functions. It is still unclear, how cognition changes during years of illness in schizophrenia.

Our aim was to analyze the change in verbal learning and memory functions in subjects with schizophrenia and healthy controls during a 9-year follow-up.

The sample was the general population based Northern Finland 1966 Birth Cohort. In 1999-2001 and in 2008-2010 field studies were performed, including repeated measures of clinical status and the California Verbal Learning Test (CVLT). CVLT was used for the estimation of the course of a possible change of verbal learning and memory during the follow-up. The sample included 41 individuals with schizophrenic psychoses and 74 non-psychotic controls.

Both cases and controls had statistically significant decline in measures of CVLT. However, the change in verbal learning and memory in the 9 -year follow-up was not statistically significantly different between cases and controls. Among cases, age of illness onset and sex had no statistically significant effect on change of verbal learning and memory.

According to our unselected, population based sample with long follow up, the impairments during the life span in verbal learning and memory in schizophrenia was not different compared to controls. These results imply that schizophrenia is not a progressing degenerative illness.