Severe traumatic brain injury and the young male syndrome

Introduction

According to hungarian neurosurgical data (2008) the severe traumatic brain injuries could be arised from crashes, falls, traffic accidents and shot-stabbed injuries, which are influenced by some risk factors. Epidemiological studies have demonstrated that severe brain injuries are tipical of age group under 45, and observable is the dominance of males between them.

In all cultures and at all ages male gender is characterized by more aggressive and competitive behavior than women (Alexander, 1979). This kind of sex differences in extreme risk taking is particularly manifested between at the age of 15-35 years. At this age they are prone to involve in high risk situations and moreover these males are mostly in single status.

The risk taking behavior of young males is explained by intrasexual selection in which the fight for the chance for reproduction is considered as an imperative part. Males were evolutionally selected for self-representing and risk taking behavior which reaches its peak at the age of 15-35 years. This phenomenon where risk taking behavior is a signaling device of male physical displays during mate choice was described and characterized by Wilson and Daly in 1985 and referred to as young male syndrome.

Hypotheses

1. Among severely head injured patients there should be a relatively higher proportion of risk taking young males at the age of 15-35 years, comparing with other subgroups.

2. We proposed that severely injured males at the of 15-35 years are more tended to taking risks when they are single comparing with young males with other marital statuses and older males.

3. We supposed that young male survivors of TBI who have a greater tendency of risk taking behavior should reach a higher score at the questionnaire aimed to assess impulsivity than non-risky young male population or older males with risky and non-risky behaviors.

Materials and methods

Subjects:

• 20 males were enrolled to this study who previously suffered severe traumatic brain injury (GCS less than 9)

• patients were recovered

• The mean age at the time point of the tests was 37.00 years (std.=11.59), while at time of injury 31.75 years (std.= 11.11).

• These patients were enlisted into two groups according to their age at injury:

Occurence of risky and non-risky behavior in relationship with the age and the marital status in our patient cohort:

Mechanisms of injury:

The mechanism of the injury was road traffic accident in 10 (50%), fall in 5 (25%), assault in 3 (15%) and other in 2 (10%) cases. The higher frequency of assaults among young males may refer to the

more common risk taking behavior in that age group.

Procedure (assesment of risky/non-risky behavior and impulsivity):

• 33 healthy volunteers assessed the behavior of injured patients (risky or non-risky)

• 10-grad Likert scale

• Summation of decisions

• Median value (= 216) was used to stratify the behavior of injured as risky or non-risky

• 12 (60%) risky and 8 (40%) non-risky cases

• In the young male group 10 patients classified as risky behavior (76.92%) while from the older males only 2 (28.57%)

• The association of risk taking and impulsivity has been assessed via the Barratt Impulsivity Scale (Version 11) (Patton et al., 1995)

This work is supported by ETT Grant 269/2009 and „Save what can be saved”-Applied neurological research using high-field magnetic resonance imaging: Grant of the EGT and Norwegian Financing mechanism and Developing Competitiveness of Universities in the South Transdanubian Region (SROP-4.2.1.B-10/2/KONV-2010-0002) as well as by MTA-PTE Clinical Neuroscience MR Research Group.

Results

SPSS 20.0

Result 1: Chi-square test; χ2= 4,432; P = 0,035 <0,05 (sign.)

Result 2: Chi-square test; χ2= 21,376; P= 0,011 <0,05 (sign.)

Result 3

:

Discussion

In case of the first hyphotesis we were able to demonstrate that young males at the age of 15-35y analyzed in our trial had a higher tendency to be involved in risky activities threatening with injury (due to adaptive effect of intrasexual competition). Severe traumatic brain injury was more frequent among young males with risk taking behavior than persons from this same age group without such behavioral pattern, or than older males.

Regarding second hyphotesis we have demonstrated that risk taking behavior as well as resultant TBI is significally more frequent in young single males than in young males with other marital statuses or in older males with different marital statuses. Our hyphotesis is also verified by a higher number of married males with non-risky behavior in the older subgroup.

We also were able to prove one part of our third assumption, namely demonstrating that impulsive behavior is significantly more common among risk taking, injury-prone young individuals than in young individuals without risk taking. We also observed that impulsivity was more characteristic for older males who were defined as risk takers than among those who were not displaying such behavioral pattern.. However, between the age and the impulsivity wasn’t found negative correlation,which is maybe due to the small number of patients.

Conclusion

The present study provided preliminary evidence for that the young male syndrome can be manifestation of such accidents caused by risk taking behavior of young males which lead to TBI and also highlighted the role of impulsivity in occurrence of severe brain injury. It’s important that our observations and results may open up novel strategies in prevention of injury and warrant further epidemiological studies and analysises in an expanded patient database.

We could be able to enroll just a small number of cases into this study, therefore we would like to extend our sample in the future.

References

Alexander, R. D. (1979). Darwinism and Human Affairs. Seattle, University of Washington.

Daly, M. and Wilson, M. (1985). Competitiveness, risk-taking, and violence: the young male syndrome. Ethology and Sociobiology 6: 59-73.

Patton, J.H., Stanford, M.S., and Barratt, E.S. (1995). Factor structure of the Barratt impulsiveness scale. J Clin Psychol 51, 768.

Number of patients Main age Std.

Between 15-35y

13 25 5,35

Above 35y 7 44,28 7,15

Risky Non-risky Risky Non-risky

Single 6 (30%) 0 0 1 (5%)

Divorced 0 0 1 (5%) 0

In relationship 1 (5%) 2 (10%) 0 0

Married 3 (15%) 1 (5%) 1 (5%) 4 (20%)

Summary 10 (50%) 3 (15%) 2 (10%) 5 (25%)

10

3 2

5

Figure 1. Connection between the age and the risk taking behavior among patients with severe traumatic brain injury

young male, risky

young male non-risky older male, risky

older male, non-risky

0 20 40 60 80 100

young, risky young, non-

risky older, risky older, non-risky

73,2

57,3

82,5

64,4

Scores of impulsivity

Figure 3. Impulsivity in correlation with risk taking behavior and age

0 1 2 3 4 5

6

6

0 0

1 1

0

3

1

0

1

0 0

2

0

1

4

Frequencies

Figure 2. Risk taking behavior, age and marital status

Young, risky, in relationship Older, risky, in relationship Young, risky, married

Older, risky, married Young, non-risky, single Older, non-risky, single Young, non-risky, divorced Older, non-risky, divorced

Young, non-risky, in relationship Older, non-risky, in relationship Young, non-risky, married

Older, non-risky, married

SROP-4.2.2./B-10/1-2010-0029

Supporting Scientific Training of Talented Youth at the University of Pécs