TLFB

The Timeline Followback (TLFB) is a calendar-based, semi-structured interview method developed by Linda and Mark Sobell for obtaining detailed daily estimates of substance use over a specified time period (typically 30–90 days). Using calendars and memory aids (holidays, personal events), respondents reconstruct their daily consumption patterns. The TLFB can quantify multiple outcomes: percent heavy drinking days, total drinks consumed, days of abstinence, and number of drinking days. Originally developed for alcohol, it has been adapted for tobacco, cannabis, opioids, and other substances. The TLFB is the standard primary outcome measure in virtually all psychedelic-assisted therapy trials for substance use disorders, including psilocybin for alcohol dependence (Bogenschutz, NYU) and psilocybin for tobacco smoking cessation (Johnson, Johns Hopkins). It has excellent test–retest reliability (r > 0.85) and good concordance with biochemical markers.