A mass panic occurs when a group acts in dangerous or destructive ways contrary to social norms due to abandoning individuality and adopting a group mentality. There are four types of mass panic that determine the police response: anger-driven, excitement-driven, desperation-driven, and fear-driven. The police must be prepared to avoid exacerbating a potential panic with either under- or over-response. Elements of an effective response include preparedness, command/communication, contingencies, and rules of engagement tailored for each panic type.