The ICD: a shared checklist for diagnosis
ICD = the International Classification of Diseases (WHO), listing symptoms and features of recognised illnesses. Why: a shared list makes two clinicians look for the same symptoms under the same rules, so they agree. Use: check present symptoms against a threshold — depression, most of the day nearly every day for at least two weeks; addiction, three or more of six features in the past year. It is not an explanation (what is there, not why) and not a treatment.
Depression: 3 core symptoms, two-week rule
Unipolar depression — mood moves downwards only; no elevated mood, unlike bipolar. Three core symptoms: persistent low mood, loss of interest and enjoyment, and reduced energy. Other common symptoms: reduced concentration, low self-esteem, guilt, a bleak view of the future, self-harm ideas, disturbed sleep, reduced appetite. Rule: most of the day, nearly every day, for at least two weeks — often left out. Name each symptom and say what it involves.
Addiction: six features, three or more
Addiction = the dependence syndrome, with six features: a strong desire or compulsion, impaired control (over starting, stopping and amount), a withdrawal state, tolerance (more for the same effect), neglect of interests, persisting despite harm. Threshold: any three, together, in the past year. Muddled: tolerance = more while using; withdrawal = unwell on stopping. Depression uses a duration rule, dependence a count rule — never swap them.
Drawn from real examiner reports.
A 2-mark describe needs two unique points
The content is a list, and lists invite repetition. "The person feels sad" and "they feel very unhappy" is one point twice, one mark. A 2-mark describe needs two unique points, from different entries — say persistent low mood and disturbed sleep. Pick from different lines, and give each a clause rather than a bare label.
A 2-mark "describe" needs two unique points, not one reworded (June 2023 P2 Q22).
Difference needs a connective word
Asked the tolerance/withdrawal difference, candidates write "tolerance is needing more; withdrawal is feeling ill on stopping" — both true but implied, one mark. The connective earns the second: needing more, whereas withdrawal is the state on stopping. Related trap: "state one feature" answered by defining the term — give a list entry, not a definition.
Difference answered as two separate definitions, the connective earning the second mark (June 2019 P1 Q6; June 2022 P1 Q7); "state one feature" answered by defining the term (June 2023 P1 Q6).
Feeling sad or doing a lot is not a diagnosis
Both reduce to everyday language — examinable errors. "Sad is depression": low mood is one item; the ICD needs it most days for two weeks, with other symptoms. "A lot means addiction": frequency is not listed; dependence needs three or more of six features in the past year. Never argue from the amount — argue from which features are present and whether the threshold is met.
Bare "withdrawal symptoms" scores nothing
The reported failure here: asked for features of addiction, most got one of two marks. The scheme wanted described features like impaired control; "withdrawal symptoms" alone scored nothing. Write the name plus a clause, not a bare label: "a withdrawal state — feeling unwell on stopping, relieved by using again". Lead with impaired control and persisting despite harm.
Features of addiction were hard; the scheme wanted impaired control, "withdrawal symptoms" was non-creditworthy, and most gained one of two marks (June 2023 P1 Q10). Depression symptoms were well answered (June 2022 P1 Q11).
Tolerance is not withdrawal
The two most-muddled features. Tolerance is needing larger amounts for the same effect, while still using. Withdrawal is feeling unwell when use stops or is reduced, relieved by using again. They point opposite ways in time — so describing withdrawal as "needing more", or tolerance as "feeling ill when you stop", swaps them and loses the mark.
A symptom is not a cause
3.1.1 lists symptoms and features — what the person experiences. It does not ask why the problem happened. Genes, thinking style and learning are separate statements, and writing about causes here scores nothing however accurate. Keep to the ICD list — described symptoms and features — and save the causal theories for the leaves that ask for them.
Candidates answered a different part of the spec than asked — therapy effectiveness rather than the question (June 2024 P1 Q15a), or nature when nurture was asked (June 2024 P1 Q13).
Unipolar vs bipolar; do not swap the rules
Two rule traps. Unipolar vs bipolar: unipolar is downwards only, whereas bipolar also has elevated mood — 3.1.1 is unipolar. Thresholds: depression a duration rule (nearly every day, two weeks), dependence a count rule (three features, past year). Attaching the two-week rule to addiction, or the three-feature rule to depression, is wrong though each fact is correct.
Match a described behaviour to a listed item
On a scenario, the detail is the only AO2 source. Not application: naming the person, the stem, a copied line. What counts: a described behaviour matched to a named ICD item, e.g. "stopped her club" = loss of interest. AO3 cannot be awarded without AO2, so apply, then evaluate.
Reach the 7-9 band with balance, not length
The 9-mark Assess is AO1 3 / AO2 3 / AO3 3; marks are lost by listing more, not evaluating. AO1: the ICD, list and rule; AO2: match details to named items, noting absences; AO3: both sides via the lenses, then a conclusion. Close: identifies the problem, explains it poorly.
Use the evaluation lenses on the ICD
AO3 uses the named lenses. Reliability: a shared list makes two clinicians agree. Objectivity: fixed criteria, not impression. Subjectivity: evidence is self-report. Validity: records that a symptom is present, not why. Generalisability: one list across many cultures.
ICD — the International Classification of Diseases, a classification system published by the World Health Organization that lists the symptoms and features of recognised illnesses, including mental health problems.
Why it matters. Without a shared list, two clinicians could reach two different diagnoses for the same person. The ICD gives them the same named symptoms to look for and the same rules about how many are needed and for how long.
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