Category: F10 F11 F12 F13 F14 F15 F16 F17 F18 F19

F18 — Mental and behavioural disorders due to use of volatile solvents: facilitator sheet

Teaching objective

For F18, the central classification question is less about distinguishing dependence from harmful use (though that distinction still applies) and more about recognising that acute intoxication itself carries meaningful medical risk, and that this category's dependence syndrome and withdrawal state, while real, are less consistently well-characterised than for substances like alcohol or opioids.

Choose material

Worked example · Case: Passed out at the party · Case: Three times this term, but no craving in between

Worked example

Show scenario

A 16-year-old has inhaled aerosol fumes on four occasions over the past two months with friends, on one occasion briefly losing consciousness during use. He has not used between these episodes, reports no craving in between, and no difficulty stopping once each episode's supply ran out. He does say he plans to avoid it now after the loss-of-consciousness episode frightened him.

1. Reveal step 1

   Step 1 — Note the pattern: use has been episodic (four occasions over two months) rather than continuous or escalating.

2. Reveal step 2

   Step 2 — Check for control difficulty and craving: he reports neither craving between episodes nor difficulty stopping once each episode ended.

3. Reveal step 3

   Step 3 — Check for harm: the loss-of-consciousness episode is clear, demonstrable physical harm directly from intoxication.

4. Reveal step 4

   Step 4 — Weigh against dependence syndrome: without control difficulty, craving, or tolerance, the fuller six-criteria cluster is not met, even though real harm has occurred.

5. Reveal step 5

   Conclusion — This is best classified as harmful use (F18.1) rather than dependence syndrome, because clear physical harm from intoxication is present without the broader dependence cluster — illustrating why harmful use is a distinct threshold, not merely a lesser degree of dependence.

Comparison points

F18 is distinguished from other categories in this block mainly by where the acute danger lies — in intoxication itself rather than primarily in withdrawal — and by its dependence syndrome being less consistently well-characterised, making harmful use a comparatively more commonly applicable classification here.

Discussion prompts

1. Prompt 1

   Without looking back at the page, state where this category's greatest acute medical danger typically lies.

2. Prompt 2

   Name the feature that distinguishes harmful use from dependence syndrome in this case.

3. Prompt 3

   Explain in one sentence why episodic use alone does not establish dependence syndrome.

Summary

Volatile solvents carry direct acute medical risk from intoxication itself; harmful use often applies even without the fuller dependence-syndrome cluster, which is less consistently established for this category than for most others in this block.

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