MicroRNAs (miRNAs) are small, non-coding RNAs that participate in the post-transcriptional regulation of messenger RNAs (mRNAs) by degrading or inhibiting translation. Some of the topical studies strongly suggest that the disorders in the normal activities of miRNAs might cause many diseases. Generally, such studies concern patient-specific expression profiles for the purposes like pruning, clustering or classification. This paper describes a novel relative coexpression measure to compute deviation in microarray expression profiles of diseased people over a set of people. This measure is used by an unsupervised algorithm of complexity O (n3 log n), where n denotes the number of miRNAs, to locate the group of miRNAs responsible for the specific disease. The results taken over the expression data of schizophrenic patients show efficiency in locating brain-enriched miRNAs, which have earlier established support to be associated with schizophrenia neuropathology.