Chunk #22 — 2. METHODS — 2.3 Measures — 2.3.4 Other substance use — 2.3.4.1

Source

Onset of opportunity to use cannabis and progression from opportunity to dependence: Are influences consistent across transitions?

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yes

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Weekly tobacco use was measured through the interview item “Was there ever a time in your life when you smoked cigarettes at least once a week for at least two months in a row?” Self-reported age of onset of weekly tobacco use was used to make time varying covariates for survival analysis.