Sexual or romantic relationships with former patients are unethical if the physician uses or exploits trust, knowledge, emotions, or influence derived from the previous professional relationship, or if a romantic relationship would otherwise foreseeably harm the individual.
Ethically you cannot have a doctor/patient (or even a former patient) relationship and a parent/child relationship with the same individual. Section 1, Paragraph 1 of the Principles of Medical Ethics Applicable to Psychiatry states that “a psychiatrist shall not gratify his or her own needs by exploiting the patient.
There are several things to take into account in determining the appropriateness of taking a patient relationship beyond clinic or hospital walls. Nurse practitioners should never date current patients. In some cases, however, a romantic relationship with a former patient may be permissible.
The professional organizations of psychology (the American Psychological Association) and psychiatry (the American Psychiatric Association) offer no explicit rules about friendships with former patients.