Final answer:
The recommended prophylactic treatment for a student with unipolar depression who has had three recurrences of depression after successful treatment with imipramine is to continue taking imipramine as an ongoing maintenance therapy.
Step-by-step explanation:
The recommended prophylactic treatment for a patient with unipolar depression who has experienced three recurrences of depression, each separated by one year, after successful treatment with imipramine 200 mg qd, would be to continue taking imipramine as an ongoing maintenance therapy. Imipramine is a tricyclic antidepressant that has been shown to be effective in preventing recurrence of depression. By continuing imipramine at the same dose, the patient may be able to prevent future depressive episodes.