The present study used carefully established phenotypes, several methods to reduce misclassification, and conservative genetic parameters. For the 35 markers investigated no evidence of linkage to manic-depressive illness was found, especially not to the markers on chromosomes 4q, 9q, and 19, which earlier has been suggested as possibly being linked to subtypes of manic-depressive illness. Close linkage to FY and SS (GYPB) was excluded for all chosen phenotypic models and to ACP1 and ADA for broader phenotypic models.