Because the symptoms are primarily internal (i.e., cognitive and somatic) others may be unaware when a child or adolescent is depressed; changes in functioning and activity, along with somatic complaints and irritability are important signs to pay attention to. Additionally, many youth with MDD will also experience anxiety, including generalized anxiety disorder, panic, or separation anxiety. In older youth, substance use is also very common among people who have depression. The prevalence of MDD increases sharply at puberty – especially among females. The rate of depression among females is about twice as high following puberty.
There are multiple risk factors for depression; among youth, family history of depression or other mental illness is a significant factor, increasing risk by two-to-four times. Early onset mood disorders tend to have a stronger genetic component than mood disorders that onset late in adolescence. Additionally, temperament and personality factors are related to risk for depression, youth who exhibit high negative affect (neuroticism) and/or perfectionistic tendencies may be at higher risk. Life events can also contribute to an individual’s risk for depression; both traumatic, one-time events and chronic stressful living conditions increase vulnerability. Research using functional neuroimaging suggests that youth with depression show abnormal activity in the default mode network during resting state, which may be related to rumination. Additionally, youth with depression often exhibit hyperactivity of the amygdala and abnormal connectivity between the anterior cingulate and the amygdala during negative face emotion processing tasks. Finally, youth who experience chronic medical problems are more likely to develop depression than their peers.