The meaning and relevance of the increased rates of neuromotoric deviation (ND) observed in patients with schizophrenia and their biological relatives remain unclear. ND could represent free-floating, independent characteristics of individuals in these families vs. signs of an increased risk for current or future mental disorder. The co-temporaneous relationship between ND and mental disorder at 6 years of age was investigated among 31 children with an increased risk for schizophrenia and similar psychoses, defined as having a mother with a history of schizophrenia or unspecified functional psychosis. As compared with high-risk cases with a low level of ND, the subgroup of 10 high-risk offspring showing notably increased rates of ND had significantly more frequent psychiatric diagnoses (typically language disorders and enuresis), poor functioning on global assessment, poor interpersonal competency and high anxiety proneness. Neuromotoric items representing “overflow” (e.g., choreatic movements, tremor) were significantly positively related to each of these mental characteristics. Among high-risk offspring, an increased rate of ND is very clearly associated with increased rates of current mental disorder, and might potentially identify a subgroup with an especially high risk for serious mental disorder in the future.