Unconscious processing of subliminal stimuli in panic disorder: A systematic review and meta-analysis

The fear of spiders: perceptual features assessed in augmented reality

Background

Persons with specific phobias typically generalize the dangerousness of the phobic animal to all members of its species, possibly as a result of malfunctioning brain circuitry normally providing quick and dirty identification of evolutionary-relevant stimuli. An objective assessment of which perceptual features make an animal more or less scary to phobic and non-phobic people would help overcome the limitations of the few studies available so far, based on self-reports.

Objective

To achieve this aim, we built an augmented reality setting where volunteers with different levels of fear of spiders were asked to make holographic spiders that look either dangerous or harmless. To reach this goal, a computerized interface allowed participants to modify the spider's perceptual features (hairiness, body/leg size, and locomotion) in real time.

Results

On average, the dangerous spiders were made hairy, thick, and moving according to spider-like locomotion; coherently, the harmless spiders were made hairless, slim, and moving according to a butterfly-like locomotion. However, these averaged preferences could not fully describe the complex relationship between perceptual preferences with each other and with arachnophobia symptoms. An example of a key finding revealed by cluster analysis is the similarity in perceptual preferences among participants with little or no fear of spiders, whereas participants with more arachnophobia symptoms expressed more varying preferences.

Conclusion

Perceptual preferences toward the spider's features were behaviorally assessed through an observational study, objectively confirming a generalization effect characterizing spider-fearful participants. These results advance our knowledge of phobic preferences and could be used to improve the acceptability of exposure therapies.

Functional correlates of subliminal stimulation in Posttraumatic Stress Disorder: Systematic review and meta-analysis

Patients with Post-traumatic stress disorder (PTSD) exposed to traumatic reminders show hyperreactivity in brain areas (e.g., amygdala) belonging or related to the Innate Alarm System (IAS), allowing the rapid processing of salient stimuli. Evidence that IAS is activated by subliminal trauma-reminders could shed a new light on the factors precipitating and perpetuating PTSD symptomatology. Thus, we systematically reviewed studies investigating neuroimaging correlates of subliminal stimulation in PTSD. Twenty-three studies were selected from the MEDLINE and Scopus® databases for a qualitative synthesis, 5 of which allowed a further meta-analysis of fMRI data. The intensity of IAS responses to subliminal trauma-related reminders ranged from a minimum in healthy controls to a maximum in the PTSD patients with the most severe (e.g., dissociative) symptoms or the least responsiveness to treatment. Comparisons with other disorders (e.g., phobias) revealed contrasting results. Our findings demonstrate the hyperactivation of areas belonging or related to IAS in response to unconscious threats that should be integrated in diagnostic as well as in therapeutic protocols.

Perceptually Visible but Emotionally Subliminal Stimuli to Improve Exposure Therapies

Subliminal stimuli are gaining growing interest due to their capability to induce desensitization to pathologically feared (e.g., phobic) pictures without inducing exaggerated emotional reactions. However, unresolved methodological issues cast significant doubt on the reliability of these findings and their interpretation. The studies most robustly assessing stimulus detection found that ~30% of the supposed-to-be-subliminal stimuli were, in fact, detected, suggesting that the beneficial effects attributed to subliminal stimuli may result from those actually seen. Nevertheless, a deeper analysis of the data underlying this misinterpretation unveils theoretical and clinical implications. Since the purpose of subliminal stimulation is to reduce the aversiveness of exposure therapies while maintaining their efficacy, researchers should measure the emotional relevance of supposed-to-be-subliminal stimuli that are, in fact, detected. A distinction is needed between perceptually- and emotionally-subliminal stimuli: the former is not consciously detected; the latter just fails to elicit emotional reactions. Emotionally-subliminal stimuli could represent an intermediate step of exposure in addition to those involving perceptually subliminal or supraliminal stimuli. Importantly, emotionally subliminal stimuli could make patients able to sustain a conscious exposure to feared stimuli without exaggeratedly reacting to them: if confirmed by empirical data, this unexpected disconfirmation of patients’ beliefs could pave the way for successful therapy while increasing their self-efficacy and compliance to treatment.

Personalized treatment - which interaction ingredients should be focused to capture the unconscious

A recent meta-analysis revealed that mental health and baseline psychological impairment affect the quality of life and outcomes in different chronic conditions. Implementing mental health care in physical care services is still insufficient. Thus, interdisciplinary communication across treatment providers is essential. The standardized language provided by the diagnostic statistical manual favors a clear conceptualization. However, this approach might not focus on the individual, as thinking in categories might impede recognizing the continuum from healthy to diseased. Psychoanalytic theory is concerned with an individual’s unconscious conflictual wishes and motivations, manifested through enactments like psychic symptoms or (maladaptive) behavior with long-term consequences if not considered. Such modifiable internal and external factors often are inadequately treated. However, together with the physical chronic condition constraints, these factors determine degrees of freedom for a self-determined existence. The effect of therapeutic interventions, and especially therapy adherence, relies on a solid therapeutic relationship. Outcome and process research still investigates the mechanism of change in psychotherapeutic treatments with psychanalysis’s focus on attachment problems. This article examines existing knowledge about the mechanism of change in psychoanalysis under the consideration of current trends emerging from psychotherapy research. A clinical example is discussed. Additionally, further directions for research are given. The theoretical frame in psychoanalytic therapies is the affect-cognitive interface. Subliminal affect-perception is enabled via awareness of subjective meanings in oneself and the other; shaping this awareness is the main intervention point. The interactional ingredients, the patient’s inherent bioenvironmental history meeting the clinician, are relevant variables. Several intrinsic, subliminal parameters relevant for changing behavior are observed. Therapeutic interventions aim at supporting the internalization of the superego’s functions and at making this ability available in moments of self-reflection. By supporting mentalization abilities, a better understanding of oneself and higher self-regulation (including emotional regulation) can lead to better judgments (application of formal logic and abstract thinking). Thus, this facilitates enduring behavior change with presumably positive effects on mental and physical health.