What are the strengths and weaknesses of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM‑5‑TR) and the International Classification of Diseases, Eleventh Revision (ICD‑11) in diagnosing inhalant‑related disorders?

Comparative Analysis of DSM-5-TR and ICD-11 for Inhalant-Related Disorders

DSM-5-TR Strengths

The DSM-5-TR provides a unified dimensional approach to inhalant use disorder that eliminates the problematic abuse-dependence distinction, using a severity-based system (2-3 criteria = mild, 4-5 = moderate, 6+ = severe) that better reflects the continuous nature of inhalant pathology. 1, 2

• Item response theory analysis demonstrates no consistent hierarchical ordering between abuse and dependence criteria for inhalants, strongly supporting the dimensional rather than categorical approach adopted in DSM-5 2
• The legal problems criterion represents the highest severity threshold, while giving up important activities provides the most accurate discrimination between severity levels 2
• DSM-5 criteria sets have been validated through extensive psychometric testing showing good test-retest reliability and unidimensional latent trait structure 1

DSM-5-TR Weaknesses

The most significant limitation is that DSM-5 does not include inhalant withdrawal as a diagnostic criterion, despite evidence that 47.8% of persons with inhalant dependence experience three or more clinically significant withdrawal symptoms. 1, 3

• The DSM-5 work group acknowledged that "some support exists" for inhalant withdrawal but concluded evidence remained insufficient, recommending further study 1
• Research demonstrates that inhalant withdrawal symptoms are nearly as common as cocaine withdrawal symptoms among dependent users, with almost equal percentages reporting clinically significant withdrawal 3
• The absence of withdrawal criteria may lead to underdiagnosis of severe inhalant use disorder and inadequate treatment planning for withdrawal management 3
• DSM-5 remains fundamentally categorical at its core, classifying based on observable symptoms without biological validation, resulting in biologically heterogeneous groups within the same diagnostic category 4, 5

ICD-11 Strengths

ICD-11 offers superior clinical utility through dimensional symptom severity ratings across six domains (positive, negative, depressive, manic, psychomotor, and cognitive symptoms) on a 4-point scale, providing flexibility for treatment planning without requiring precise temporal calculations. 4, 6

• Field studies with 928 clinicians showed higher diagnostic accuracy, faster time to diagnosis, and superior perceived clinical utility for ICD-11 compared to ICD-10, with 82.5% to 83.9% rating it as quite or extremely easy to use, accurate, clear, and understandable 4, 5, 6
• The dimensional approach provides more nuanced profiles for contexts where detailed information is needed beyond overall severity to inform treatment, particularly for psychotherapy planning 1, 6
• ICD-11 emphasizes documenting episodicity and current status to capture longitudinal patterns beyond categorical diagnosis 4, 5
• Global applicability was a core development priority, with extensive international field testing across WHO regions 1

ICD-11 Weaknesses

When excluding entirely new diagnostic categories, ICD-11 showed no significant difference in diagnostic accuracy, goodness of fit, clarity, or time required for diagnosis compared to ICD-10, indicating advantages are largely limited to new categories rather than improvements in existing substance use disorder diagnoses. 1, 4, 5

• Interrater reliability was high for psychotic disorders but only moderate for mood disorders in ecological field studies 1
• Field study samples may be biased toward practitioners positive about ICD-11, particularly for online studies where participants registered voluntarily 1
• Vignette studies used prototypic cases that might not accurately reflect real-life clinical complexity, highlighting the need for further ecological field studies under regular clinical conditions 1
• Like DSM-5, ICD-11 lacks biological validation and remains fundamentally categorical despite dimensional expansions 4, 5

Critical Diagnostic Gaps for Inhalants

Both systems fail to adequately address the unique neurotoxic profile of inhalants, which cause multisystem damage affecting pulmonary, cardiac, renal, hematologic, gastrointestinal, hepatic, and neurologic systems, leading to chronic psychiatric, cognitive, behavioral, and anatomical deficits. 7

• Neither system provides specific guidance for assessing the extensive organ damage patterns unique to inhalants 7
• Laboratory testing for inhalant abuse is very limited, and neither classification system addresses this diagnostic challenge 7
• The distinct pharmacologic categories of inhalants (volatile solvents/anesthetic gases, nitrous oxide, and volatile alkyl nitrites) have different mechanisms of action and toxicities that are not differentiated in either system 7

Practical Clinical Recommendations

Use ICD-11's dimensional severity ratings across all six symptom domains at each assessment to capture the full clinical picture of inhalant-related cognitive and psychiatric impairment, while recognizing that neither system adequately addresses inhalant withdrawal or organ-specific toxicity. 4, 6, 7

• Supplement diagnostic assessment with systematic evaluation of multisystem organ damage through targeted physical examination and imaging studies 7
• Monitor for withdrawal symptoms despite their absence from formal criteria, as nearly half of dependent users experience clinically significant withdrawal 3
• Create detailed life charts documenting longitudinal symptom patterns, as inhalant-related diagnoses frequently evolve over time 4, 5
• Use structured diagnostic interviews rather than unstructured clinical assessment to reduce diagnostic bias 4, 6