One of the most common forms of self-medication in capitalist societies surely has to be retail therapy.  Is there really a problem that can't be solved by a new pair of shoes, or the latest iWhatever?  Interestingly, one of the problems people might be trying to overcome is the fear of death.

The insecurity and anxiety caused by the fear of death has some interesting effects on people.  When people are reminded of their inevitable demise, they become more rooted in their outlook on life, this is called Terror Management Theory.  For example, we start to see people with similar values and beliefs more positively, and people with different beliefs more negatively than we ordinarily would (1).  We also become more reluctant to use cultural symbols like flags in improper ways (2).  

Since some of the more salient values of Western culture are materialistic in nature - earn more money, accumulate more stuff, etc., - it might be the case that being reminded of our mortality makes us more materialistic, as we move deeper into our adopted values.

Local businesses attempt practical application of Terror Management Theory (Newsbie Pix)

Tim Kasser and Ken Sheldon did a couple of studies in 2000 to look into this (3).  The exercise they used to induce mortality salience is just about as unpleasant as you'd expect - participants had to write about their feelings about the own death.  The control group wrote about listening to music, which is obviously does not increase your awareness of death (unless your favourite band is Cannibal Corpse, perhaps).

After this, the people who wrote about death expected to be earning more in 15 years than the controls, and expected to be spending more money on "pleasure items."  In a second study, participants played a forest management game, and after writing about death, people were more willing to use up the resources of the forest, and were more interested in making profit.   Curiously, another study found that materialistic people have more dreams about death (4).

Playing a game does not mean they would act this way if they were really head of a timber company, but it's an interesting behavioural measure to go along with the self-report.  There might be some parallels to other low-consequence scenarios (cutting yourself a larger slice of pizza, for example!).  Maybe.  The aim here was to investigate greed, a typical characteristic of materialistic people. 

So although a self-report and imagined exercise are not definitive, they at least give an idea of the direction of causality, to go along with correlational data linking materialism with concerns about one's death (5) - this study also found partial mediation of the relationship by insecurity, which fits with the general idea that higher materialism comes about to make up for some personal insecurity, which itself can be triggered by the fear of death.  

You could make some speculations linking these ideas to George Bush's advice to go shopping following the 9/11 attack.  People have their own theories on why W gave that advice, which we won't go into here, but maybe here's an idea on why people were so ready to take the advice.

References:

(1) Greenberg, J., Pyszczynski, T., Solomon, S., Rosenblatt, A., Veeder, M., Kirkland, S., et al. (1990). Evidence for terror management theory II: The effects of mortality salience on reactions to those who threaten or bolster the cultural worldview. Journal of Personality and Social Psychology, 58(2), 308-318. 

(2) Greenberg, J., Porteus, J., Simon, L.,&Pyszczynski, T. (1995). Evidence of a terror management function of cultural icons: The effects of mortality salience on the inappropriate use of cherished cultural symbols. Personality and Social Psychology Bulletin, 21(11), 1221-1228. 

(3) Kasser, T.,&Sheldon, K. (2000). Of wealth and death: Materialism, mortality salience, and consumption behavior. Psychological Science, 11(4), 348-351.

(4) Kasser, T.,&Grow Kasser, V. (2001). The dreams of people high and low in materialism. Journal of Economic Psychology, 22(6), 693-719.

(5) Christopher, A., Drummond, K., Jones, J., Marek, P.,&Therriault, K. (2006). Beliefs about one's own death, personal insecurity, and materialism. Personality and Individual Differences, 40(3), 441-451.