Electrophysiological responses to affective stimuli in Mexican Americans: Relationship to alcohol dependence and personality traits

Abstract

The relationship between the P450 component elicited by affective stimuli and: a personal history of alcohol dependence, antisocial personality disorder/conduct disorder (ASPD/CD) or affective anxiety disorders (ANYAXAF) was examined in Mexican Americans, a group with high rates of heavy drinking. Data from two hundred and twenty two young adults between the ages of 18 and 30 were used in the analyses. ERPs were collected using a task that required discrimination between faces with neutral, sad and happy facial expressions. DSM-IIIR diagnoses were obtained using a structured interview and personality traits were indexed using the Maudsley personality inventory. Men had significantly diminished P450 responses, when compared to women which were further reduced in men with ASPD/CD; whereas, a significant increase in P450 amplitudes was seen in those participants with ANYAXAF. P450 amplitudes were also significantly increased in men with high extraversion scores and in women with high neuroticism scores. No significant associations were seen between the P450 amplitude and the diagnosis of alcohol dependence. These data suggest that interpretations of P450 responses in Mexican Americans need to take into account the interactions between gender, the affective valence of the eliciting stimuli, as well as psychiatric status.

Figure 1

Grand averages of event-related potentials (ERPs) elicited by a facial discrimination task in Mexican American young adults. Averages are presented for frontal (Fz) and central (Cz) and parietal (Pz) leads as elicited by each of the three types of facial expressions (happy, neutral, sad). The P450 component is indicated; solid lines are for male participants and dashed lines for females.

Figure 2

P450 Amplitude (microvolts) to happy, neutral, and sad facial expressions in those participants with a select anxiety or affective disorder (AXAF) in the black bars, and in those without a select anxiety or affective disorder (no AXAF) in the open bars. Values are given as means±SEM. Asterisk indicates a significant difference between groups. (*p<0.05, ** p<0.01)

Figure 3

P450 Amplitude (microvolts) to happy, neutral, and sad facial expressions in male participants with conduct disorder and/or antisocial personality disorder (ASPD/CD) in the black bars and in those without conduct disorder and/or antisocial personality disorder (no ASPD/CD) in the open bars. Upper graph is data from Frontal Cortical Leads. Lower graph is from centro-parietal leads. Data are presented as means±SEM. Asterisks indicate significant difference between the groups. **P<0.01)