Rahe (1970)

Context: Hans Selye (1930) suggested a link between psychological state of stress and physical illness.

Hawkins et al. (1957) conducted a study with TB paitents and non TB workers. (They were matched by race, gender, age and income) and Hawkins et al. found a corrletation between 'distuburing occurances' in the prior two years with the TB paitents. 

In the 1960s Rahe and Homles decided there was need for a measure that assess stress-related life changes. In order to produce such a measure they analysed the case histories of more than 5000 patients, producing a list of 43 crtitical life events. 

Aims: Rahe et al. (1970) aimed to conduct a prospective study using a normal population to investigate if there is a relationship between life events/changes and illness. (a prospective study is one where a group of partcipants is identified at the start of the study and followed forward in time). 

This study involved 2684 men who were naval and marine personnel serving aboard three US Navy cruisers: two were aircraft carriers involved in military operations off the coast of Vietnam and the others were based in the Mediterranean. 

The mean age of the participants across the three cruisers was 22.3 years, and participants came from a range of backgroundsin terms of education, rank and maritime experience. Of the intial sample 10% of were 'lost' as a result being transferred off the ships.

Participants were required to fill in the military verison of the SRE (sex and relationship education). This is a pen and paper self-administered questionnaire documenting significant changes in a person's life relating to: personal, family, community, social, religous, economic, occupational, residential and health experiences. Each sailor completed the SRE every six months orver a period of two years prior to a six to eight-month tour of duty at sea. 

Each life changing event was assigned a LCU (life change unit). This value reflects the severity and adjustment needed for that particular event. As the ships returned rom overseas assignments a research phsyican went aboard and reviewed the sailors' health records

Neither the medical team or the sailors on the ships knew the aims of this experiemtent. 

Findings: The relationship between the pre-cruise total life change units and the cruise period illness was exmined. This covariables were (a) the two-year cruise period (b) cruise-period illness. The correlation between these covariables produced no significant correlation.

However, here as a significant correlation. Hoervrt, there was a significant positive correlation between (a) the six-month period prior to the cruise and (b) cruise-period illness. A correlation coefficient was calculated to be. 118, which may sound like a weak correlation, but given the number of participants involved was actually highly significant. 

Conclusions: The results of this prospective study supports the notion of a linear relationships between participants' TLCU (total life change units) score of their subsequent illness rate. Futher analysis of the data suggested that the life- change information predicted illness better in the older paricipants (over 21 years old) and the married enlisred men than in the group of young, single sailors. 

Cohen et al. (1991,1993) asked participants to complete the SRRS to asses their current level of stress in terms of LCUs. The participants were then given nasal drops. The experimental group were given nasal drops contaning a virus that causes the common cold, whereas the control group had non-infectious nasal drops. Pariticipants were quaranined and monitored for approximately seven days. The results of the studies showed that participants with higher reported levels of stress were more likely ro be infected with the cold. 

Glaser et al. (1984) measured the immune systems activity in students taking important medical exams. Blood samples were taken one month before exmas (low stress) and during the exam period itself (high stress). The immune systems was concluded to be more vulenable to illness and infection in the exam period as there was a lower production of NK (natural killer) cell activity in the blood. 

Moos and Swindle (1990) produced the LISRES (Life Stressors and Social Resoucres Inventory). They identified eight areas of ongoing life stressors: health, home, fiance, work, partner, child, extended family and friends.