Towards a psychopathology specific to Substance Use Disorder: Should emotional responses to life events be included?
Introduction
Post-traumatic stress disorder (PTSD) is a severe, psychologically disruptive, often chronic condition that is triggered by traumatic life events that lead to symptoms such as persistent re-experiencing of the event, avoidance of feelings, thoughts, conversations or places associated with the trauma, adverse alterations in cognition and mood, and hyperarousal [1].
With the publication of the new DSM-5, greater attention is now being paid to the set of behavioral symptoms that may accompany PTSD; this set includes reckless or self-destructive behaviors. There is, in fact, a growing body of data dealing with the relationships between PTSD and maladaptive, risk-taking behaviors [2], [3]. In particular, previous studies have documented a strong connection between PTSD and Substance Use Disorder (SUD) [4], [5].
As the relationship between PTSD and SUD is not yet fully understood, several hypotheses have been formulated. The “self-medication” hypothesis (SMH), in which PTSD came first, was initially postulated by Khantzian [6]. It states that substances are used to relieve the painful symptoms of PTSD, and consequently subjects develop a SUD. The “high-risk” hypothesis, in which PTSD can develop from SUD, suggests that a dangerous lifestyle induced by SUD increases a subject's exposure to loss and traumatic events, and therefore raises the likelihood of PTSD [4], [7]. A causal relationship may not necessarily link PTSD and SUD, considering that a third factor could mediate PTSD/SUD comorbidity – a shared pathway or substrate – that predisposes PTSD and SUD subjects to develop these two disorders, so allowing a unified perspective (the “shared vulnerability” hypothesis).
Lastly, it could be that PTSD is best understood through a dimensional conceptualization viewed alongside the spectra of symptom severity, nature of the stressor, and responses to trauma (PTSD spectrum) [8]. This conceptualization allows us to study the PTSD spectrum-SUD relationship by adopting a unified perspective. Of course, correlations between the severity of heroin addiction and severity of the PTSD spectrum would support the self-medication hypothesis. However, in the case of primary heroin addiction, a unified perspective would be supported if correlations were demonstrated between the severity of heroin use disorder and the chronologically later severity of the PTSD spectrum. On the other hand, the severity of the PTSD spectrum that arises during addiction should be lower in the presence of a high dosage of opioid agonist medication. Agonist opioid medications are, in fact, able to limit PTSD insurgency after traumatic war events [9], [10], [11]. Any finding of high correlations between heroin addiction and PTSD spectrum will support the idea that a PTSD spectrum should be considered as an integral part of the psychopathology of the addiction, as a reaction to stress [12].
By studying life events (loss and traumatic experiences) and emotional responses to them in heroin-dependent patients before and after the age reached at the onset of dependence, we demonstrated that emotional reactivity was greater after the beginning of addiction had occurred. This increase in the intensity of emotive reactions during a drug addiction history seems to prearrange a PTSD spectrum resulting from the addictive process [13]. We had previously found positive correlations between the severity of heroin addiction, the dose of opioid medication, and the severity of the PTSD spectrum [14].
In Heroin Use Disorder (HUD) patients characterized by the lifetime absence of exposure to actual or threatened death, serious injury, or sexual violence, this PTSD spectrum, resulting from the addictive process, could display a high degree of severity. We evaluated the reactivity of the posttraumatic spectrum to loss and traumatic events included in a group of acute, catastrophic events (the 2009 L'Aquila earthquake) where the survivors experienced PTSD, and in a group of long-lasting HUD subjects who had never been exposed to catastrophic incidents. The magnitude of emotional reaction turned out to be similar in HUD subjects and in PTSD subjects who were themselves earthquake survivors. Heroin addictive behavior could have an overall effect similar to that of a single exposure to an extreme event such as an earthquake. In other words, HUD patients seem to over-react to stress [15]. Short-lasting opioids, such as heroin, are marked out by a destabilizing effect on the endogenous opioid system, determining various psychopathological consequences, including hypersensitivity to stressful stimuli (PTSD spectrum). On the other hand, long-lasting methadone does not act as a drug of abuse, but as a medication, normalizing responses to stress [16]. The use of heroin after a traumatic event remains compatible with the self-medication hypothesis, but the PTSD spectrum seems to be a standard feature of the progression of heroin addiction.
Addiction is a mental illness in which psychiatric conditions imply serious burdens. Psychopathological symptoms in Substance Use Disorder patients are usually viewed as being assignable to the context of a personality trait or comorbidity, refusing the presence of a specific psychopathology that could only be related to the addiction process. The V.P. Dole Research Group at the University of Pisa, Italy, has studied the possible definition of a specific psychopathological dimension in Substance Use Disorders. In Heroin Use Disorder subjects, using a factor analysis on all the 90 items included in the SCL-90 questionnaire, a 5-factor solution had been found. The first factor accounted for a depressive “worthlessness and being trapped” dimension; the second factor picked out a “somatic symptoms” dimension; the third identified a ‘sensitivity-psychoticism’ dimension; the fourth a ‘panic-anxiety’ dimension; and the fifth a ‘violence-suicide’ dimension [17]. These results were replicated by applying the same analysis to another Italian sample of 1195 heroin addicts entering a Therapeutic Community Treatment [18]. Further studies confirmed the clusters of symptoms, independently of demographic and clinical characteristics, active heroin use [19], lifetime psychiatric problems [20], kind of treatment received [18], and, especially, other substances used by the patient like alcohol or cocaine [21]. Moreover, these clusters were closely linked with the behavioral covariate of craving in HUD patients [22] and were able to distinguish patients affected by addiction from those affected by psychiatric diseases such as major depressive disorder [23] and obesity [24]. Studies are in progress to verify whether these dimensions can discriminate HUD patients from gamblers. In summary, our studies seem to suggest the trait- rather than the state-dependent nature of the psychopathological dimensions of SUD introduced by us.
The aim of the present study has been to further support the view that there is a psychopathology that is unique to SUD by verifying whether it is independent of the severity of emotional responses to life events, and by testing whether reactivity to life events can be included in the specific psychopathology of SUD patients. To do that we analyzed multivariate correlations between psychopathology and reactivity to life events, and we compared the quality and quantity of the five SCL-90 dimensions previously identified, by dividing HUD patients on the basis of the severity of their emotional responses to life events (whether traumatic or due to a loss). As our criterion, therefore, we used the severity that differentiated people who did develop (High PTSD spectrum) from those who did not develop (Low PTSD spectrum) a clinical post-traumatic stress disorder (PTSD) after the 2009 L'Aquila (Italy) earthquake. Our expectation was that severity, but not typology, can differentiate HUD subgroups. We can, in fact, assume that emotional responses are only a proxy for the seriousness of an illness and that a psychopathology specific to HUD is independent of the severity of that disease. Finding a significant correlation between psychopathology and the PTSD spectrum would strengthen the case for the inclusion of PTSD as an as additional factor attesting to a psychopathology that would be specific to that kind of addiction.
Section snippets
Design of the study
A naturalistic comparative cohort study was designed. Patients were evaluated on one occasion only during an Agonist Opioid Treatment (AOT) performed in three distinct locations in Tuscany, Italy. This study was carried out according to a non-interventional protocol. All patients gave their informed consent to the anonymous use of their clinical data for this independent study.
Sample
The sample consisted of 93 patients, with a diagnosis of HUD according to DSM-5 criteria. We did not use specific
Results
Forty-one (44.1%) patients showed a TALS total score of < 32 and were clustered in the L-PTSD/S group. Mean age was 41.00 ± 8.4; 37 (90.2%) were males. 52 (55.9%) subjects showed a TALS total score > 32 and fitted into the H-PTSD/S group. Out of those 52, 35 (67.3%) were males. Mean age was 40.44 ± 10.1. Males were more frequent in the L-PTSD/S group (chi = 6.89; p = 0.009). No other differences emerged from the demographic data.
Table 1 shows the results of canonical correlation analysis. Only one
Discussion
In HUD patients, psychopathology and emotional responses to life events were closely related. Patients with more severe “worthlessness-being trapped” and “violence-suicide” psychopathology showed high scores for “grief reactions”, “re-experiencing, numbing” and “arousal symptoms”. They also presented more frequent PTSD spectrum “personality traits”. Patients marked out by a high level of “panic anxiety” reported more severe “emotional, physical and cognitive responses to loss and traumas”.
Conclusions
In HUD patients who had never been exposed to actual or threatened death, serious injury, or sexual violence, the “Worthlessness-Being Trapped” and “Violence-Suicide” dimensions were closely linked with lifetime symptoms, behaviors and personal characteristics that could be manifestations springing from the development of a stress response syndrome (PTSD spectrum). On the other hand, the typology of psychopathology was independent of the magnitude of these emotional responses to traumatic and
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