Lifetime prevalence ≠ life-long suffering

📘 Key Terminology

1. Lifetime Prevalence

The percentage of people who have ever met the criteria for a disorder at any time in their life.

Even one treated episode of depression 10 years ago counts.

Says nothing about duration or current suffering.

2. YLD (Years Lived with Disability)

A burden-of-disease metric from WHO / IHME.

Combines:

Duration of suffering

Severity of impairment (disability weight)

YLD is a better reflection of actual suffering over time, and is directly correlated with severity.

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🔢 How long is the suffering for each severity level?

Exact duration varies, but research (especially from NIMH and WHO) gives average durations and recurrence risk per disorder. Here's a summary across severity levels:

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⚖️ Estimated Duration by Severity

Severity Examples Typical Duration (per episode or lifetime) YLD Burden

Severe Schizophrenia, Bipolar I, severe MDD, severe ASD - Schizophrenia: lifelong (average ~30–40 years) <br> - Severe MDD: recurrent, 10+ episodes, each lasting ~6–12 months <br> - Bipolar I: lifelong, episodic <br> - Autism: lifelong Very high (up to 0.6 YLD per year)

Moderate PTSD, Bipolar II, OCD, moderate MDD - PTSD: 1–5 years (can be chronic) <br> - Bipolar II: lifelong but milder episodes <br> - OCD: often chronic or recurrent <br> - Moderate MDD: 6–9 months per episode, some recurrence Moderate–high (0.3–0.4 YLD/year)

Mild Adjustment disorder, mild anxiety, single episode depression - Often resolves within a few months to 1 year <br> - Often no recurrence <br> - May not need treatment Low (0.1–0.2 YLD/year)

> 🔹 Note: YLD values are per year of illness; total YLD = disability weight × years with condition.

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🧠 Key Takeaways:

Lifetime prevalence overstates total suffering — it includes many people who fully recover.

YLD gives a clearer view of total pain, burden, and cost to society.

The most serious 5–7% cause decades of suffering and drive most of the healthcare and social costs.

Mild disorders are common but brief.

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