The expression of emotions in depression and schizophrenia
Berembaum and Oltmanns (1992) examined a sample of patients diagnosed with schizophrenia and depression and examined facial expressions in response to watching movies.
Man uses two forms of communication: logic and analog. Verbal language falls into the first category, therefore it uses the word to communicate and is usually a form of communication that we are aware of and that we frequently adapt based on the context in which we find ourselves. Analogic communication refers instead to that type of language that concerns the movements of the body and the mimicry of the face (kinesic), the position of the body in space (proxemic), the variations of the voice (paralinguistic) and physical contact (haptic) . About 70% of the information that emerges in a dialogue is non-verbal cues; the indices to which we pay the most attention during a conversation are inherent to facial mimicry.
A descriptive tool of known renown and use in the study of facial expressions is the Facial Action Coding System developed by Ekman and Friesen in 1978. The FACS is considered the most important manual for encoding facial movements, taking into consideration the muscle movements that lead to expressive facial changes called Action Units (AU). The AU classified in the second edition (2002) are 41, it is necessary to specify that there is no one-to-one relationship between these and the facial muscles since the same muscle can contribute to the formation of multiple AUs and the same can be made up of different muscles. The manual describes the intensities of the action units as a function of 5 letters (A, B, C, D, E) which indicate an increasing intensity; AUs are also classified also by asymmetry, described with the letter L (left) and R (right), based on the side of the face where the emotion is expressed; some of the most frequent AUs are shown in TAB 1.
TAB. 1: Facial Action Coding System
In the clinical and experimental field, numerous studies have examined the gestures and expressive modulation of emotions in psychopathological disorders, in addition, attention to non-verbal behavior represents an important factor within the therapeutic relationship, allowing you to focus and take into account particular aspects that emerge during the dialogue. In the literature, particular attention has been paid to the analysis of these aspects in subjects with depression and schizophrenia.
In one study (Steimer-Krause, 1990) emotional expression was examined in schizophrenic patients during a dialogue with an interlocutor and, through FACS, a decrease in the repertoire and frequency of facial expressions was observed; specifically, there was a significant reduction in AU 1,2,4,6,7 which occur in the upper part of the face, while the lower part was not modified. The AUs highlighted above are characteristics of expressions such as surprise and fear, but also a fundamental part of speech accompaniment, to emphasize sentences and maintain the attention of the interlocutor through the so-called illustrative gestures (non-verbal gestures that accompany and mark the speech ). The lack or reduction of these during a dialogue contributes to a feeling of less interest in the discussion and greater emotional detachment from what is expressed verbally. The study showed that the reduction of the illustrators indirectly reverberated on the gestures of the interlocutors, bringing a decrease also in the latter.
A reduction of expressiveness in the upper part of the face analogous to schizophrenic patients was also found in a study (Heller, 1994) that examined depressed subjects, dividing the sample into patients who had attempted suicide and not. During the interview, in talking about suicidal intentions with the patients of the first group, a reduction of the AU 1,2,4 emerged which, as underlined above, serve to support the exposure; in addition, patients tended to avoid eye contact with the clinician while talking about their experiences.
As far as inter-diagnostic differences are concerned, Berembaum and Oltmanns (1992) examined a sample of patients diagnosed with schizophrenia and depression and examined facial expressions in response to watching movies. The study showed a greater reduction of facial expressiveness in schizophrenic patients compared to patients with depression, despite the self report reports on the emotions experienced were similar; the authors comment on this fact explaining that the reduction in expressiveness could be linked to mimic characteristics of these patients rather than to a real decrease in emotional experience.
Gaebel (2004) also highlighted that hypo-mimic in depressed and schizophrenic subjects would be attributable to the lower intensity and frequency of the illustrative signals AU 1,2,4 (therefore raising and frowning) compared to healthy controls. No differences were found between depressed, schizophrenic and controls patients in the expression mode of AU 14 (asymmetric smile), AU 17 (chin wrinkling) and AU 20 (downward stretching of the lips) that usually refer to negative emotions, although healthy subjects tend to exhibit them less frequently.
Again with reference to the comparison between the previous diagnostic categories, Trémeau and colleagues (2005) did not highlight any particular differences in facial emotions between groups of depressed and schizophrenic patients, where the former seem to be slightly more expressive, except for positive emotions, in line with Berembaum and Oltmanns (1992). In literature this figure seems to be confirmed by another study (Ekman & Rosenmberg, 2005), where in response to funny videos the depressed patients expressed less joy and more anger and contempt in response to negative stimuli.
In conclusion, from the literature it emerges that both diagnostic categories, albeit in different ways, exhibit a reduction in the facial repertoire, more inherent in the upper part of the face; there is also a general tendency to express less expressions of happiness in the presence of positive stimuli and to present more frequently negative emotions, such as disgust and contempt (Bergman, 2012).
Within the same diagnostic category, an alteration of expressiveness directly proportional to the severity of the disorder also emerged, therefore a greater frequency of emotions such as sadness and disgust in subjects with greater depression than in subjects with minor depression (Ekman, Matsumoto & Friesen , 2005) and a more marked hypo-mimic, as well as a greater frequency of negative emotions expressed, in hospitalized schizophrenic patients compared to outpatients (Steimer-Krause, 1990).