Which of the following best defines a mental disorder?

A mental disorder is best defined as a psychological condition impairing functioning. This definition highlights the essential aspect of mental disorders: they significantly impact an individual's ability to function in various areas of life, including social, occupational, and personal domains.

Mental disorders can include a variety of conditions such as depression, anxiety disorders, schizophrenia, and more, all of which can disrupt a person's thoughts, emotions, and behaviors, ultimately hindering their capacity to lead a fulfilling life. Recognizing a mental disorder involves understanding that it is not simply a momentary issue or a choice, but rather a persistent condition that requires attention and, often, treatment.

In contrast, the other options do not encapsulate the complexity and severity associated with mental disorders. A temporary emotional response refers to short-lived feelings, which do not equate to a sustained psychological condition. A social conflict represents interpersonal issues without inherently implying psychological impairment. Lastly, a behavioral choice made by individuals overlooks the broader context of mental health, which includes underlying psychological factors rather than just observable actions. Thus, the first choice clearly aligns with the established criteria for defining a mental disorder.