Which of the following disorders is included in Axis I of the DSM-IV?

Axis I of the DSM-IV is specifically designed to categorize clinical disorders that present a significant impairment in functioning or require clinical attention. Autism spectrum disorder falls under this axis as it is classified as a mental disorder that impacts social interaction, communication, and behavior. The inclusion of Autism spectrum disorder in Axis I highlights its recognition as a condition that necessitates treatment and can significantly affect day-to-day functioning.

In contrast, personality disorders and physical conditions are classified differently within the DSM. Personality disorders are categorized under Axis II, which deals with enduring patterns of behavior and inner experiences that significantly deviate from cultural expectations. Similarly, physical conditions, while they can have a profound impact on psychological wellbeing, are typically referenced elsewhere in the manual, such as in the context of medical conditions, rather than as clinical disorders under Axis I. Developmental delay is often placed within the broader category of developmental disorders, which can also fall under Axis II, aligning with the idea that these are more stable and long-standing than the episodic nature of the disorders that occupy Axis I.

Thus, Autism spectrum disorder stands out as the correct choice under Axis I due to its direct implications for treatment and the immediate impact it has on an individual’s functioning.