One of the most important things for a person to understand about dating someone with depression is boundaries. Depression is a serious mental illness and a leading cause of suicide. People coping with depression may not always know healthy ways to do so and may treat their loved ones disrespectfully. They may expect others to take care of them without reciprocating, or may use threats of suicide to control the relationship. Make sure your daughter understands that this kind of behavior is abusive and that she is not responsible for treating and curing her boyfriend's depression, nor is she obligated to allow him to do or have whatever he wants because he is depressed. It is reasonable for her to expect her boyfriend to get professional help in dealing with his illness, and for her to expect that he be willing to work on getting better.

The partner of a depressed person must understand that her emotional needs are just as important as those of her partner. If your daughter's boyfriend is not able to see through his depression well enough to respect her needs, he is not ready for a relationship. At the same time, feeling needed and responsible for someone else and being able to meet the emotional needs of another person can be an important boost to his self-esteem.

Anyone who loves someone struggling with depression will want to know what she can do to help him. Help your daughter understand that her job is to help her boyfriend bear the pain, anxiety, numbness, sadness and other unpleasant aspects of depression, but not to try to fix his problems or make the depression go away. Most people with depression have bad days and good days; encourage your daughter to help her boyfriend enjoy the good days to the fullest and remember that they exist during the bad days, but not to force him to cheer him up or try to make the bad days go away. Advise her that if she can help her boyfriend bear with the depression and not feel alone during the worst times, she is doing her part as his girlfriend.

Have a conversation with your daughter about her own mental health. Falling for someone with depression indicates a certain degree of empathy and may be a sign that she struggles with depression as well. If this is the case, the empathy she and her boyfriend share can be used in a healthy way, but it's also important that two depressed people avoid encouraging unhealthy worldviews in each other. Talk to your daughter about making sure that both she and her boyfriend have a healthy emotional support structure outside of one another.