It is not known whether psychological stress suppresses host resistance to infection. To investigate this issue, we prospectively studied the relation between psychological stress and the frequency of documented clinical colds among subjects intentionally exposed to respiratory viruses.

OBJECTIVES. This study was conducted to test the supposition that both smoking and consuming alcohol suppress host resistance to viral infections. METHODS. The relations between smoking, alcohol consumption, and the incidence of documented clinical colds were prospectively studied among 391 subjects intentionally exposed to one of five respiratory viruses and 26 subjects given saline. Clinical colds were defined as clinical symptoms verified by the isolation of virus or by an increase in virus-specific antibody titer. Analyses included control variables for demographics; body weight; virus; and environmental, immunological and psychological factors. RESULTS. Smokers were at greater risk for developing colds than nonsmokers because smokers were more likely both to develop infections and to develop illness following infection. Greater numbers of alcoholic drinks (up to three or four per day) were associated with decreased risk for developing colds because drinking was associated with decreased illness following infection. However, the benefits of drinking occurred only among nonsmokers. CONCLUSIONS. Susceptibility to colds was increased by smoking. Although alcohol consumption did not influence risk of clinical illness for smokers, moderate alcohol consumption was associated with decreased risk for nonsmokers.

Toxoplasma gondiiis known to induce specific behavioural changes in its intermediate hosts. This is usually considered to be an evolutionary adaptation aimed to increase the probability of transmission of the parasite into its definitive host, the cat, by predation. In rodents an increase of reaction time as well as many other specific behavioural patterns have been observed. Here we report the results of our double blind study showing the significantly longer reaction times of 60 subjects with latent toxoplasmosis in comparison with those of 56 controls. Moreover, the existence of a positive correlation between length of infection and mean reaction time suggested that slow and cumulative effects of latent toxoplasmosis rather than a one-step (and possibly transient) effect of acute toxoplasmosis disease are responsible for the decrease of psychomotor performance of infected subjects. To our knowledge, this is the first study confirming the existence of such parasite-induced changes in human behaviour that could be considered in evolutionary history of the human species as adaptive from the point of view of parasite transmission.

Well-being at work has been shown to be influenced by job characteristics and individual differences in coping styles. This study investigated the relationships between job demands, control, social support, efforts, rewards, coping, and attributional style in predicting anxiety, depression, and job satisfaction in a sample of 307 university employees from the UK. Results were compared to those from a sample of 120 members of the general population. Workplace demands, intrinsic and extrinsic effort, and negative coping and attributional behaviors were associated with high levels of depression and anxiety and low job satisfaction in university employees. Rewards, social support, job control, and positive coping and attributional behaviors were associated with lower levels of depression and anxiety and high job satisfaction. The study adds to the growing research on university samples by showing that a transactional approach should be adopted. This has implications for interventions and suggests that rather than just trying to change job characteristics one should identify at-risk individuals in this population and help them adopt appropriate positive coping styles.