واکنش پذیری استرس به روان پریشی: شواهد برای یک مسیر موثر به روان پریشی

Abstract This paper will review a series of studies using the Experience Sampling Method that suggest that altered sensitivity to stress is an endophenotype for psychosis. The Experience Sampling Method is a structured diary technique allowing the assessment of emotional reactivity to stressors occurring in normal daily life. Elevated emotional reactivity to stress was found in subjects vulnerable to psychosis, suggesting that affective responses to stressors in the flow of daily life are an indicator of genetic and/or environmental liability to psychosis. Indeed, the small stressors in daily life associated with affective responses also predict more intense moment-to-moment variation of subtle positive psychotic experiences. Increased emotional reactivity was found to be independent from cognitive impairments, and argued to constitute evidence of an affective pathway to psychosis that may underlie a more episodic, reactive, good-outcome type of psychosis. Evidence for this hypothesis was found in data suggesting that the experience of stressful life events and early trauma were associated with increased stress-sensitivity, and that women were more likely to display elevated stress-reactivity. These findings are discussed in the light of recent biological and psychological mechanisms.

Introduction The search for causal mechanisms of psychotic disorders has led to an increased interest in the study of underlying vulnerability substrates, the so-called endophenotypes (Tsuang, 2001 and Weinberger, 1999). Endophenotypes are more closely related to the genetic aetiology and its interaction with environmental risks, and thus may reveal underlying causal mechanisms that lead to the development of psychotic symptoms (Claridge, 1994). Since schizophrenia is characterized by a heterogeneous clinical expression and since multiple factors are argued to be on the causal pathway to psychosis, it is attractive to hypothesize that several endophenotypes contribute to the development of psychosis, possibly independent from each other. The current paper will focus on aberrations in sensitivity to stress that may be considered an endophenotype of psychosis, reflecting underlying gene-environment interactions associated with the impact of trauma and stressful life events in vulnerable individuals, and will give an overview of accumulating evidence for what we have called an “affective pathway to psychosis”.

Conclusion This review showed cumulative evidence supporting the construct of an affective pathway to psychosis. ESM was used to demonstrate that aberrant emotional reactivity to daily stress may constitute part of the liability to psychosis, which is independent from cognitive impairments (Fig. 3). It was hypothesized that altered stress-sensitivity may be the underlying pathway leading to a more episodic, good-outcome type of psychosis characterized by a predominance of positive symptoms seen more frequently in women. In addition, there is evidence that part of the alterations in stress-sensitivity are the result of the enduring impact of early environmental risks: the data suggest that the experience of prior life events and childhood trauma influenced emotional reactivity to daily stress. Finally, it was shown that altered sensitivity to stress is also expressed as increased moment-to-moment intensity of psychotic experiences in reaction to stress, possibly reflecting underlying dopaminergic dynamics. Evidence for the affective pathway to psychosis. Fig. 3. Evidence for the affective pathway to psychosis. Figure options The data demonstrate the importance of studying independent endophenotypes underlying different clinical expressions in order to better understand the causal mechanisms leading to psychosis. The study of emotional and psychotic reactivity to stress may aid in elucidating biological mechanisms underlying the positive symptoms of psychosis. In addition, it might provide a powerful paradigm to investigate gene-environment interactions in psychosis (Caspi & Moffitt, 2006).