Persistent smoking has been associated with prospective memory deficits in the past (PM: remembering future activities or events), yet no research to date has explored whether regular exposure to second-hand smoke (SHS) also damages everyday PM.

The present assessed whether SHS leads to reduced PM functioning by comparing a group of non-smokers who had been exposed to SHS on a weekly basis for several years (the SHS group), a group of non-smokers who had not been exposed to SHS (the non-SHS group) and a group of current smokers.

If SHS does damage PM then this group should show reduced performance akin to those expected in current smokers.

An existing- groups design was used to compare the SHS group, the non-SHS group, and a group of current smokers. Scores on the Cambridge Prospective Memory Test (CAMPROMPT: an objective measure of time- and event- based PM) constituted the main PM dependent measure. Age, mood, IQ, and other drug use (alcohol, smoking, and cannabis) were also measured. Anyone who reported using an illegal drug (ecstasy, cannabis) was omitted from the study.

After observing no between-group differences on age, mood, IQ and alcohol use, the SHS group and current smokers showed significant reductions in the performance on CAMPROMPT when compared to non-smokers who had never been exposed to SHS.

Everyday PM deficits are linked to SHS, adding weight to the dangers of exposure to other peoples smoke.