| dc.description.abstract | Background. This study was designed to investigate the relationship between psychopathology and decoding of social stimuli. Various types of psychopathology can be considered as maladaptive functioning of innate defence mechanisms to social stress and threat. An example of such an innate defence mechanism is the fight – flight system. According to Gilbert (2001) major depressive disorder and impulsive aggressive disorder can be interpreted in terms of a malfunctioning fight – flight system. In this study I assume that impulsive aggression and major depressive disorder are opposites in terms of the fight – flight system: whereas defences are blocked in patients with major depressive disorder they are executed to easily in patients with impulsive aggressive disorder. To investigate this assumption I studied the perception of social stimuli in impulsive aggressive patients and in patients who suffer from major depression. I tested a series of related hypothesis on the association between psychopathology and the decoding of social stimuli. The following hypotheses were tested: 1) Depressed patients report higher levels of submission than patients with impulsive aggressive disorder; 2) Patients with impulsive aggressive disorder report higher level of aggression and hostility than depressed patients; 3) Submissive behaviour is positively correlated with the response latency time to the Emotional Stroop Task (EST); 4) Compared to depressed men and women, patients with impulsive aggressive disorder show a shorter response latency time to the EST; 5) Subjects with impulsive aggressive disorder show a shorter response latency time to the unconscious (masked) version of the EST than to the conscious (unmasked) condition of the EST; 6) Severity of depression is positively correlated to the response latency time to the EST; 7) Aggression and impulsiveness are negatively correlated to the response latency time to the EST; 8) Depressed women show a shorter response latency time to the EST when compared to depressed men. Method. Twenty-seven outpatients of the Mental Health Care Friesland participated in this study. They were seven men and six women with major depressive disorder and fourteen men with impulsive aggressive disorder. To test the perception of social stimuli an Emotional Stroop Task was used. Participants were shown neutral, happy and angry facial expressions in two conditions of the Emotional Stroop Task. The faces were presented in two conditions: unconsciously (i.e. exposure time between 6 and 13 ms) and consciously. Results. The first hypothesis that depressed patients were more submissive than patients with impulsive aggressive disorder was confirmed. In line with the second hypothesis, aggressive patients tended to be more hostile and aggressive than depressed patients. The patients group did not differ in respect to self-reported depression or impulsiveness. In both groups the response latencies to the conscious condition of the EST were significantly higher than those to the unconscious condition. In the depressed patients this effect was confined to the men only. The response latencies did not differ between the different facially expressed emotions. In aggressive patients, but not in depressed patients, self-reported submission was positively correlated to the response latency to the unconscious condition of the EST. For the conscious condition of the EST a tendency in the same direction was observed. The fourth hypothesis has to be rejected: depressed patients and aggressive patients did not perform differently on the EST. Furthermore, patients with impulsive aggressive disorder show a shorter response latency time to the unconscious condition of the EST than to the conscious condition. No significant associations between severity of depression, aggression and impulsiveness and the response latency time to the EST were found in this study. Finally, in line with hypothesis eight, depressed women demonstrate a shorter response latency to the conscious condition of the EST when compared to depressed men. Discussion. Based on the present findings the hypothesis that major depressive disorder and impulsive aggressive disorder are opposites in terms of the fight – flight system needs to be refuted, but possible that the role of the fight – flight system differs between impulsive aggressive patients and depressed patients. | |
