Classification of Intellectual Disability
This patient has mild intellectual disability. 1
Rationale Based on DSM-5 Criteria
The classification is determined by adaptive functioning across conceptual, social, and practical domains, not by IQ score alone, as emphasized by the American Academy of Child and Adolescent Psychiatry. 1 While the IQ of 60 falls within the traditional range for mild intellectual disability (IQ 50-69), 2, 3 the definitive classification must be based on the patient's functional capabilities. 1
Key Clinical Features Supporting Mild Classification
Conceptual Domain:
- Difficulty learning basic reading and writing skills indicates impairment in academic learning, which is characteristic of mild intellectual disability where difficulties typically become apparent at school age. 1
- The patient can understand and process information at a basic level, though complex reasoning is impaired. 1
Practical Domain:
- The ability to perform self-care activities independently is the critical distinguishing feature. 1 This includes personal care responsibilities such as hygiene, dressing, and basic daily living tasks. 1
- Needing help with more complex tasks (such as managing finances, completing forms, or making complex life decisions) is consistent with mild intellectual disability, where individuals require assistance with higher-level practical reasoning. 1
Social Domain:
- While not explicitly stated in the case, individuals with mild intellectual disability typically have relative strengths in social reasoning and can recognize others' thoughts and feelings. 1
Why Not Other Classifications
Not Moderate Intellectual Disability:
- Individuals with moderate intellectual disability (IQ 35-49) typically require substantial support for self-care activities, not just complex tasks. 1 They would need ongoing assistance with basic daily living skills. 1
Not Severe or Profound Intellectual Disability:
- These classifications involve much more extensive support needs across all domains of adaptive functioning, with severe limitations in communication and self-care that are not present in this patient. 2, 4
Critical Clinical Considerations
The DSM-5 explicitly states that IQ scores are "approximations of conceptual functioning but may be insufficient to assess reasoning in real life situations and mastery of practical skills." 1 Therefore, the profile of adaptive functioning—particularly the preserved ability to perform self-care independently—takes precedence over the numerical IQ value in determining severity classification. 1
The patient's functional profile showing independence in self-care but dependence for complex tasks aligns precisely with the mild intellectual disability classification, where individuals can achieve partial independence in adulthood with appropriate supports. 1