Q: My best friend has been having major mood swings lately. One second, she's talking a mile a minute and jumping from subject to subject; the next, she seems depressed and angry. My brother had these symptoms right before he was diagnosed with bipolar disorder. How can I talk to my friend about my suspicions without her becoming upset?

A: Your question is a common one, but that doesn't mean there's an easy or obvious answer. As you likely know from your experience with your brother, bipolar disorder is a serious illness that impacts a person's mood, energy level, and functioning in many areasincluding social, academic, and occupational.

You may also be aware from your own experience that, while biploar disorder is serious, it is treatable when properly diagnosed and managed. You may also already know that there are different forms of bipolar disorder, each defined by a unique combination of mood episodes (depressed, manic, hypomanic, and mixed). As such, the behavior patterns of people with bipolar disorder can look very different from each other. While it sounds like your friend may be experiencing mood shifts typical of certain forms of bipolar disorder, other conditions must be ruled out by a professional health-care provider.

That said, you do not need to know (nor is it your responsibility to figure out) the exact nature of your friend's erratic behavior before you talk to her about your concerns. It is certainly appropriate for you to share your thoughts with her sooner rather than later. However, when communicating with anyone about sensitive topics, the right timing is very important. It's best to initiate such a discussion when your friend's mood is relatively stable. When she is particularly depressed and angry or notably energetic and unfocused, it's best not to approach her because she might not be able to hear your message as you intend it to be heard.

When the timing is right, simple statements, such as "I care about you" and "You are important to me," can be helpful ways to begin. You can let her know that you have seen a change in her behavior, and it concerns you. You might ask her if she has noticed this, too. It can also be beneficial to let your friend know that you'd like to help if she is struggling with somethingand that you're interested in her hearing her ideas as well. What is considered helpful to one person may not be for another, even if each is experiencing the same problem. Offer to listen to your friend while reminding her that she is not alone.

Remember that what your friend is experiencing may or may not be related to bipolar disorder, and she may or may not already be receiving treatment for the cause of her behavioral changes. When you express your concerns, keep in mind that the situation is likely complicated and probably won't be able to be resolved immediately. Just let her know that you will continue to support herand that you will not judge her or make her feel as though she has done something wrong. Make it clear that the reason you approached her is because you care about her.

It's extremely important to remember that that when people experience extreme shifts in mood, it is not uncommon for suicidal thoughts to emerge. If your friend expresses such thoughts, or demonstrates any violent or suicidal behavior, immediately call 911 for assistance. Finally, do not forget to take care of yourself during this process. Having friends and loved ones struggling with conditions such as bipolar disorder can be stressful and emotionally tiring. It is important for you and for the well-being of your relationships to seek support when you need it. As is the case for your friend, contacting a health-care professional is always a good place to start.

Stuart Koman, Ph.D., is president and CEO of Walden Behavioral Care in Waltham, Massachusetts; a principal at the Executive Performance Group; and a senior clinical advisor to the Public Consulting Group. Before that time, he was president of Charles River Health Management, a psychiatric contract management division of Community Care, Inc., and served as a member of the Governing Board of the American Psychological Association's practice division from 1992 to 2000. Koman is also an author and co-editor of the Handbook of Adolescents and Family Therapy.