Depression

🔍 When to Suspect

Persistent (≥2 weeks) low mood, loss of interest or pleasure (anhedonia), or fatigue, representing a change from normal functioning

From the full topic in The Ocean Library: Depression

🧭 When to suspect

Depression is a clinical diagnosis. Suspect it in anyone with persistent low mood, loss of interest or pleasure (anhedonia), or fatigue that is present most of the day, nearly every day, for at least 2 weeks and represents a change from their usual functioning. Look for the associated features – disturbed sleep (classically early-morning waking), appetite or weight change, poor concentration, feelings of guilt or worthlessness, diurnal mood variation, and suicidal ideation.

A simple case-finding screen is the two Whooley questions: during the last month, has the person often been bothered by (1) feeling down, depressed or hopeless, and (2) having little interest or pleasure in doing things? A "yes" to either prompts a fuller assessment. Severity is judged not by a symptom count alone but by the combination of symptoms, duration and the impact on personal and social functioning.

NICE NG222 (2022) replaced the old grades (subthreshold, mild, moderate, severe) with two categories, using a PHQ-9 score of 16 as the indicative threshold:

PHQ-9 score	Severity (NICE NG222)	First-line approach
< 16	Less severe (encompasses subthreshold and mild)	Menu of options; do not routinely offer an antidepressant first-line – least intrusive first (guided self-help)
≥ 16	More severe (encompasses moderate and severe)	Offer a choice including a combination of an antidepressant and individual CBT, or either alone

The conventional PHQ-9 bands (5–9 mild, 10–14 moderate, 15–19 moderately severe, 20–27 severe) remain useful for tracking response over time, but management decisions follow the NICE less/more severe split and the person's preferences.

Source: NICE NG222

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