Signs of a mental health crisis may include:

Inability to think clearly is a key indicator of a mental health crisis. This can manifest as confusion, difficulty making decisions, or problems with concentration and focus. When individuals are in a mental health crisis, their cognitive functions can be significantly impaired due to overwhelming stress, anxiety, or other emotional disturbances. This disruption can hinder their ability to process information and respond to situations appropriately, making it a critical sign to recognize in assessing someone's mental well-being.

The other options, while they may appear to represent states of mental health, do not align with typical signs of a crisis. High energy levels, increased concentration, and excessive optimism can sometimes reflect a heightened state of mental health or even conditions like mania, but they do not inherently indicate a crisis. Recognizing the ability to think clearly as a fundamental aspect of mental health helps in identifying those who may be in urgent need of support and intervention.