As discussed in the first installment of this series on How Thinking Contributes to Depression, mood disturbance often occurs not merely as a result of unfavorable circumstances or events, but oftentimes because of the way in which a person perceives or interprets an event. Two people might experience the same situation (e.g., receive a poor test grade) but have very different thoughts or interpretations of the situation; one person might interpret the failing grade as a sign