Recreational drug use and fluctuating asymmetry: testing the handicap principle.

Zahavi's handicap principle suggests that only organisms with good genetic quality can afford to engage in costly behaviors. Recreational drug use can be harmful to one's health and therefore might be viewed as a costly signal of one's genetic quality. One of the measurements of genetic quality is bodily symmetry assessed by fluctuating asymmetry. If unhealthy drug use is a behavioral example of Zahavi's handicap principle, then men who use different stimulants or recreational drugs should be more symmetrical than men who do not use them at all or use them only in low quantity. The aim of this study was to examine the relationships between drug use and fluctuating asymmetry. The subjects were 190 young women and 202 young men. Six bilaterally symmetrical traits were measured: length of II-V digits, wrist breadth, and ear height. Questionnaires included questions about smoking, alcohol drinking, drug use, and designer drug use. There was no relationship between bodily symmetry and smoking frequency, alcohol drinking frequency, drug or designer drug use, total substance use, age of smoking initiation, or reason of this initiation. The results indicate that drug use does not reflect genetic quality and does not necessarily relate to the handicap hypothesis.