When two variables have a significant correlation one assume there
is something causing them to go together. A correlation is a description of a
relationship between two variables, which are either directly related to each
other, or they share a common cause (Aron, Aron, & Coupe, 2009). A
direction of causality is a path of causal effect, therefore X may be thought
to cause Y, or Y may be thought to cause X, or that something else causes X and
Y (Aron, Aron, & Coups, 2009). If anxiety and depression are correlated,
there are three possible directions of causality that might explain this
correlation. One causality could be that anxiety causes depression. A second
causality could be that depression causes anxiety. A third causality could be
that there is an environmental stimuli that causes both anxiety and depression.
One may be able to rule out one or more of these three possible directions of
causality based on additional knowledge of the situation (Aron, Aron, &
Coups, 2009). In order to do so one must investigate the situation.
Aron, A., Aron, E. N., & Coups, E. (2009).
Statistics for psychology (5th ed.). Upper Saddle River, NJ: Pearson Prentice
Hall.
