Final answer:
The necessary and sufficient conditions for being diagnosed with a mental disorder are atypical, maladaptive, distressed by behavior/thinking, and irrational.
Step-by-step explanation:
The necessary and sufficient conditions for being diagnosed with a mental disorder are reactions to life's challenges that are atypical, maladaptive, distressed by behavior/thinking, and irrational. These conditions are used to determine if a person's reactions to life's challenges are indicative of a mental disorder. For example, if someone's behavior or thinking is significantly different from what is considered normal or adapted, and it causes distress to them or impairs their daily functioning, it may suggest the presence of a mental disorder.