A nurse is caring for a client who has a depressive disorder. Which of the following factors should the nurse identify as a risk factor for developing this condition?

A. Prior head trauma: While head trauma can contribute to cognitive changes or neurological deficits, it is not a primary risk factor for developing depressive disorders. It may increase vulnerability but is less directly associated than neurotransmitter imbalances. B. High level of norepinephrine: Elevated norepinephrine is generally associated with hyperarousal or anxiety states, not depression. Depressive disorders are more commonly linked to deficiencies rather than excesses of certain neurotransmitters. C. Serotonin deficiency: Low levels of serotonin are strongly implicated in the pathophysiology of depressive disorders. Serotonin regulates mood, sleep, and appetite, and a deficiency can contribute to symptoms such as low mood, anhedonia, and sleep disturbances. D. Viral infections: While some infections can impact mood indirectly through inflammation or chronic illness, viral infections are not considered a direct risk factor for the development of depressive disorders. They may exacerbate existing depression but are not primary causes.