Which of the following conditions does valerian aim to address?

Valerian is an herbal supplement commonly used for its sedative and calming effects, particularly to enhance sleep quality and manage sleep disturbances. It is well-known for helping to reduce the time it takes to fall asleep and improving the overall quality of sleep. The active compounds in valerian root are thought to increase the levels of certain neurotransmitters involved in sleep regulation.

The other conditions listed do not align with valerian's primary uses. While valerian may have a mild effect on mood, it is not typically recognized as a treatment for depression, chronic pain, or bipolar disorder, which usually require more targeted therapeutic approaches or medications. Thus, the primary focus of valerian is on addressing sleep-related issues, making it the correct choice in this context.