The Correlation between Methadone Dosages among Pairs of Heroin Users in Romantic Relationships and among Pairs of Heroin Users Who Are Siblings

This study explores whether an individual’s methadone dose is influenced by the level of another individual’s dose as a function of their relationship. Thirty-four subjects were recruited in this study; 16 subjects were in a partner relationship and 18 subjects were siblings. Multiple regression analysis revealed that the dose of one member of the dyad was a predictor of the dose of the other member of the dyad. Mean difference in dose was negatively associated with the correlation coefficient in sibling dyads but not partner dyads. Analysis of the dose curves showed that all partner dyads demonstrated a “collinearity pattern” or “coexistence pattern,” but a “distinct trend pattern” was only noted in sibling dyads. Our results suggest that there is a relationship between the methadone doses of members of a dyad and that this phenomenon is more remarkable in partnership dyads than sibling dyads.