Van der Does A J, Dingemans P M, Linszen D H, Nugter M A, Scholte W F
Department of Psychiatry, Leiden University, The Netherlands.
Psychol Med. 1993 Aug;23(3):745-53. doi: 10.1017/s0033291700025514.
The relationships among symptoms, cognitive functioning and social functioning were investigated in 60 patients with recent-onset schizophrenia. Positive symptoms were unrelated to cognitive measures. Disorganization and depressive symptoms were correlated significantly with Card Sorting performance. Furthermore, only negative symptoms were correlated significantly with social functioning. These results replicate earlier studies with chronic and mixed samples, and support the validity of disorganization as a separate symptom dimension. In contrast to most previous studies, no significant correlations were found between negative symptoms and cognitive measures. However, some evidence was found for a non-linear association between negative symptoms had several cognitive measures. The variation explained by a curvilinear model was not high, but for some cognitive measures this model was clearly superior to a linear model. If replicated, this finding supports the position that cross-sectionally measured negative symptoms cannot be viewed as a unitary concept.
