Adolescent depression may be linked to early family relationships, according to research performed in Hong Kong and published in the "Journal of Family Psychology," in 2009. This study found that in families who reported poor relationships, depressive symptoms in adolescent children were significantly higher than in families where relationships were reported as healthy. Families with hostile or negative relationships may benefit from therapeutic intervention to promote more positive interaction and avoid depression.

Poor relationships between parents may contribute to more negative relationships between parents and children, according to University of Michigan research. This study, published in the "Journal of Marriage and Family" in 2010, found that negative relationships between parents as well as divorce were both associated with negativity in mother-child relationships. This study also found that these effects were more pronounced in families where the parents remained together, suggesting that the continuous conflict encourages more conflict in other relationships. Parents who choose to remain together -- and even those who don't -- may benefit from intervention to improve interactions.

Poor relationships that include violence may keep a cycle of aggression going within families, according to research out of the University of Southern California. This study, published in the "Journal of Clinical, Child and Adolescent Psychology" in 2007, found that children showed more aggressive behaviors when their parent of the same sex exhibited more aggression in familial interactions. Because poor relationships within the family may not only encourage more inter-family hostility but also aggressive problem solving outside the family, care should be taken to address relationships as well as problem-solving strategies so that families can more easily heal.

Early relationships may change physical responses, leading to increased stress responses for family members, according to research conducted through Arizona State University and published in "Hormones and Behavior" in 2009. This study found that individuals with negative familial relationships in childhood had higher levels of cortisol, a stress hormone linked to anxiety as well as heart disease. Because poor relationships within families can lead to higher hormone levels -- and the physical consequences that go along with this -- early intervention is vital to reduce effects on family members.