Summary
Aim
To confirm the presence of typical autonomic response associated to distinguished psychopathological conditions.
Methods
A sample of 60 subjects (Table I) was consecutively examined in an outpatient clinical center with the following diagnoses according to the DSM-IV-TR criteria 1: Generalized Anxiety Disorder (GAD, n = 24), Major Depression Episode (MDE, n = 14), Panic Disorder (PAD, n = 12), Obsessive-Compulsive Disorder (OCD, n = 10). Inclusion exclusion criteria: subjects with physical illness or comorbidity with other I or II axis disorders of the DSM IV were excluded. At the time of diagnosis, all the subjects had been free of any medication for at last of three months. All the subjects underwent a continuous and simultaneous registration of four physiological parameters strictly connected with autonomic arousal (psycho-physiological profile or PPP): skin conductance response (SCR), heart rate (HR), peripheral temperature (PT), and electromyography of the forehead muscle (EMG). All the parameters were continuously registered in three consecutive phases: baseline (registration at rest), stress presentation, and recovery. Each phase lasted 6 minutes, with a stop of 10 seconds between the phases as well as 3 minutes of adaptation before the start of the registration. Data from the four groups of subjects regarding each of the registered physiological parameters were compared by using the mean value of the last minute of the registration at rest, and two activation indexes: “response to stress” and “recovery after stress.” The Kruskal- Wallis (Table IV) and Mann-Whitney (Table V) statistical tests were utilized to evaluate differences between groups. Furthermore, for each physiological parameter and for each diagnostic group, the mean values of the three different phases (last minute of the rest, first minute of the stress, and last minute of the recovery) were compared in order to evaluate trends in the four PPP parameters. Friedman and Wilcoxon’s statistical tests (Table III) were utilized to evaluate possible differences among the three phases, and the significance of the changes that occurred between one phase and the others.
Results
Results from the statistical analysis showed that SCR mean values are much higher for GAD and PAD patients than for MDE and OCD (p < .001). The amplitude of the galvanic response was also significantly different (p < .05; Fig. 1). Furthermore, the HR response was higher in GAD than in the other three groups (p < .02). Therefore, OCD and MDE patients seem to be characterized by a low, stable profile of all the considered parameters.
Conclusions
The results confirm the relevance of the psycho-physiological evaluation as part of a multidimensional diagnosis in clinical psychology and psychopathology, partially in accordance with the Gray and Fowles model. Furthermore, obtained data suggest the interesting hypothesis that the PPP may be used as a new tool for differential diagnosis, such that some psychopathological syndromes would be represented not only by a single measure (such as skin conductance which is recommended in the DSM-IV-TR only in regard to anxiety disorders), but by a specific and typical autonomic response pattern.