In the November 2013 issue of Personality and Social Psychology Bulletin , researchers Wing-Yee Cheung, Tim Wildschut, Constantine Sedikides, Erica Hepper, Jamie Arndt, and Ad Vingerhoets suggested that nostalgia may actually make people more optimistic about the future. In one study, college students were asked to write a short essay about a past event that made them feel nostalgic or a past event that seemed ordinary. The rating system determined that making people write about a nostalgic event made people feel more nostalgic and also slightly more positive than writing about an ordinary event.
The researchers suggested that thinking of happy memories while going through tough times can make people feel more happy and optimisitic. This notion stands to reason from a hypnotherapeutic point of view, as well.
In my stop smoking program, I have people go back to happy childhood memories and tell them that “every time you remember a happy memory you will be become deeper relaxed and feel more certain that you can become an ex-smoker permanently.”