Which of the following are signs that a mental health crisis may be occurring?

The selection of rapid mood changes and self-harm as a sign that a mental health crisis may be occurring is accurate because these behaviors are often indicative of significant emotional distress or instability. Rapid mood changes can signal the presence of underlying mental health conditions, such as bipolar disorder or severe anxiety, which may lead to a crisis if not managed properly. Self-harm, such as cutting or other forms of self-injury, is a critical sign that an individual is experiencing unbearable emotional pain and may pose a risk to their safety. These signs necessitate immediate attention and intervention from mental health professionals to prevent escalation and provide appropriate support.

In contrast, consistent happiness and stability generally indicate good mental health, rather than a crisis. Isolation from friends and family can suggest struggles with mental health, but it's not always indicative of an active crisis; some might engage in isolation during low periods without it leading to a crisis. Increased social activities typically reflect positive mental health and resilience, showing that the individual is engaging with their community, which does not suggest a crisis. Together, these comparisons highlight why the correct answer focuses on behaviors associated with distress and self-harm.