What's the difference between 'intermediate family' and 'immediate family'?

I'm looking to find the difference in the two descriptions of family - 'intermediate' and 'immediate'. Does anybody know the technical difference?|||When studying groups or "families" of things, the results are sometimes divided into three categories: the lowest extreme family, the highest extreme family and the intermediate family. Here's an example from a study of schizophrenics





"Results


A well-performing, an impaired, and an intermediate family cluster emerged from the analysis."





The legal definition for "immediate" family varies from state to state but here's a typical one:





"Immediate family refers to a person鈥檚 parents, spouse, children, and siblings and will also include the parent鈥檚 spouse. Usually step children and adopted children and their spouses are included under the purview of immediate family."





I've noticed that "intermediate family" is frequently misused in place of "immediate family" as if they had the same meaning.