We assessed possible Axis I and Axis II disorders in two groups of aggressive drivers (n=20, court-referred; n=10, self-referred) and 30 non-aggressive driver controls, using the SCID and SCID-II. Aggressive drivers were more likely than controls to be positive for any Axis I and Axis II disorders. They were also more likely to meet the criteria for Intermittent Explosive Disorder (IED), current or past alcohol or substance abuse or dependence and Antisocial PD and Borderline PD. The self-referred aggressive drivers were more likely than court-referred aggressive drivers to meet the criteria for a current or past Anxiety Disorder. Re-analysis of aggressive driver data on the basis of presence or absence of IED revealed differences only in Axis II disorders: those with IED were more likely to meet the criteria for any Axis II disorder and Antisocial PD.
Aggressive driving, and its more severe form popularly known as “road rage”, have recently attracted notable public attention. For example, traffic safety officials have noted that aggressive driving is on a par with DWI/DUI as a risk factor for motor vehicle accidents (MVAs). Martinez (1997) estimated that one-third of all personal injury MVAs and two-thirds of MVA fatalities were due to aggressive driving. Snyder (1997) estimated that 50% of all MVA crashes involved aggressive driving.
Just who the aggressive driver is, has only recently attracted the attention of psychology and psychiatry. For example, Larson (1996) has described a typology of aggressive drivers in his book, Steering Clear of Highway Madness. He has also described a questionnaire, The Driver's Stress Profile, to identify these individuals and measure improvement from treatment.
Deffenbacher and colleagues (Deffenbacher, Oetting, & Lynch, 1994) have developed a measure to identify potential aggressive drivers, the Driving Anger Scale, and have shown that college students in the upper quartile of this scale improve with psychological treatments ( Deffenbacher, Huff, Lynch, Oetting, & Salvatore, 2000). Those high in driving anger also tended to have relatively elevated scores on several well-known psychological tests such as trait anger ( Spielberger, 1988) and trait anxiety ( Spielberger, 1983).
Neither of these two research teams has directly addressed the issue of whether aggressive drivers have diagnosable psychopathology. Larson hints that part of his population of self-referred aggressive drivers were high in Type A, Coronary Prone Behavior, but this is not a diagnosable condition.
One potential diagnosis which comes to mind for this population is Intermittent Explosive Disorder (IED), described by DSM-IV (APA, 1994) as one of the impulse control disorders whose essential feature is, “the occurrence of discrete episodes of failure to resist aggressive impulses in serious assaultive acts or destruction of property” (p. 609). IED is itself an under-studied condition (McElroy, 1999; Monopolis & Lion, 1983; Felthous, Bryant, Wingerter, & Barratt, 1991). McElroy, Soutullo, Beckman, Taylor and Keck (1998) assessed 27 individuals with potential IED using the SCID (Structured Clinical Interview for DSM-IV (First et al., 1996a and First et al., 1996b)). They found a high level of mood disorders; specifically 89% met the criteria for a current mood disorder while 93% with lifetime mood disorders. They also found 37% with current anxiety disorder and 48% with lifetime anxiety disorder and 48% with lifetime alcohol or substance abuse. The authors speculated that IED might belong in the affective spectrum. This excellent study suffers from at least two deficits: no control population was studied and Axis II disorders were assessed clinically, rather than with a structured interview.
In order to shed light on our earlier rhetorical question of who is the aggressive driver, we administered structured psychiatric interviews to court- and self-referred aggressive drivers who were candidates for treatment in a focused cognitive behavioral treatment program. Data on their potential psychiatric morbidity as well as from a group of non-patient controls constitute the data for this paper.
