Comorbidity
Comorbidity is the simultaneous occurrence of more than one diagnosis. Comorbidity complicates research on the etiology and outcome of a single diagnosis, such as depression, because the comorbid diagnosis might in fact be the main determinant of outcome. Table 3 lists commonly comorbid conditions.
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Table 3. Comorbid disorders to suspect |
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• Panic disorder |
The coexistence of multiple diagnoses is the norm rather than the exception in childhood depression. In fact, only about 20% of depressed teens will be diagnosed with uncomplicated depression. More than 50% of depressed adolescents will simultaneously meet criteria for an anxiety disorder; more than 50% will meet criteria for oppositional defiant or conduct disorder; and a similar percentage will have attention deficit hyperactivity disorder. Several studies indicate that almost 60% of patients have diagnoses in all four categories. Similar results emerge from studies of populations with a primary diagnosis of attention deficit disorder where high rates of depression and anxiety disorders are found. Many studies of comorbidity do not even include substance abuse or eating disorders, particularly bulimia nervosa, as an area of inquiry. Panic disorder and obsessive compulsive disorder are commonly seen with a complicating depression in our specialty mood disorders clinic.
Current research is ascertaining the effect of comorbid diagnoses on response to various treatments and on outcome. It happens, however, that many treatments overlap so that a comorbid diagnosis can guide treatment choices. Comorbid conditions, such as anxiety disorders and behavioural disorders, might respond well to specific pharmacotherapy or might respond to the nonpharmacologic measures used to treat depression. Behavioural, cognitive, and coping strategies are helpful for panic disorder, bulimia nervosa, obsessive compulsive disorder, and attentional or impulse control disorders, and as part of the management of conduct or substance abuse disorders.
Prognosis and outcome
Longitudinal studies of child and adolescent depression have recently been published. A long-term follow up of children seen at the Maudsley Hospital found that milder depressive symptoms appear to predict various nonaffective psychiatric problems and personality dysfunction in adulthood, while more severe acute depressive episodes are more likely to be followed by adult affective illness. In the shorter term, the morbidity over 3 to 5 years for adolescents with a major depression is alarming: impaired psychological, academic, and social functioning; recurrent depression; and a disturbing rate of serious suicide attempts. These data indicate that we should take adolescent depression seriously. ■