Lifelong opioidergic vulnerability through early life separation: a recent extension of the false suffocation alarm theory of panic disorder

Biological and cognitive theories explaining panic disorder: A narrative review

The current narrative review summarizes and examines several theories of panic disorder (PD) including biological theories, encompassing neurochemical factors, metabolic and genetic theories, respiratory and hyperventilation theories and cognitive theory. Biological theories have informed the development of psychopharmacological treatments; however, they may be limited in their utility given the efficacy of psychological treatments. In particular, behavioral and, more recently, cognitive models have garnered support due to the efficacy of cognitive-behavior therapy (CBT) in treating PD. The role of combination treatments has been found to be superior in the treatment of PD in particular cases, lending support for the need for an integrated approach and model for PD given that the etiology of PD is complex and multifactorial.

Beauty and Uncertainty as Transformative Factors: A Free Energy Principle Account of Aesthetic Diagnosis and Intervention in Gestalt Psychotherapy

Drawing from field theory, Gestalt therapy conceives psychological suffering and psychotherapy as two intentional field phenomena, where unprocessed and chaotic experiences seek the opportunity to emerge and be assimilated through the contact between the patient and the therapist (i.e., the intentionality of contacting). This therapeutic approach is based on the therapist’s aesthetic experience of his/her embodied presence in the flow of the healing process because (1) the perception of beauty can provide the therapist with feedback on the assimilation of unprocessed experiences; (2) the therapist’s attentional focus on intrinsic aesthetic diagnostic criteria can facilitate the modification of rigid psychopathological fields by supporting the openness to novel experiences. The aim of the present manuscript is to review recent evidence from psychophysiology, neuroaesthetic research, and neurocomputational models of cognition, such as the free energy principle (FEP), which support the notion of the therapeutic potential of aesthetic sensibility in Gestalt psychotherapy. Drawing from neuroimaging data, psychophysiology and recent neurocognitive accounts of aesthetic perception, we propose a novel interpretation of the sense of beauty as a self-generated reward motivating us to assimilate an ever-greater spectrum of sensory and affective states in our predictive representation of ourselves and the world and supporting the intentionality of contact. Expecting beauty, in the psychotherapeutic encounter, can help therapists tolerate uncertainty avoiding impulsive behaviours and to stay tuned to the process of change.

A Narrative Literature Review of the Epidemiology, Etiology, and Treatment of Co-Occurring Panic Disorder and Opioid Use Disorder

OBJECTIVE

Panic disorder is a debilitating psychiatric disorder that often co-occurs with substance use disorders. Given the current opioid epidemic, the high reported rates of comorbid panic disorder and opioid use disorder are particularly concerning. In this narrative review, we describe the literature on panic disorder and opioid use disorder co-occurrence.

METHODS

86 studies, 26 reviews, 2 commentaries, and 5 guidelines pertaining to opioid use disorder, panic disorder, and their comorbidity were identified using all EBSCO databases, PubMed, and Google Scholar.

RESULTS

First, we review epidemiological literature on the prevalence of the comorbid condition above and beyond each disorder on its own. Additionally, we discuss the challenges that complicate the differential diagnosis of panic disorder and opioid use disorder and contribute to difficulties establishing rates of comorbidity. Second, we review three theoretical models that have been proposed to explain high rates of co-occurring panic disorder and opioid use disorder: the precipitation hypothesis, the self-medication hypothesis, and the shared vulnerability hypothesis. Third, we outline how co-occurring panic and opioid use disorder may impact treatment for each condition.

CONCLUSION

Based on findings in the field, we provide recommendations for future research as well as treatment considerations for co-occurring panic and opioid use disorders.

A Novel Maintenance Therapeutic for Opioid Use Disorder

Opioid use disorder (OUD) is a major socioeconomic burden. An ideal OUD pharmacotherapy will mitigate the suffering associated with opioid-withdrawal, inhibit the effects of high efficacy opioids, and minimize opioid-cravings while being safe and accessible to a diverse patient population. Although current OUD pharmacotherapies inhibit the euphoric effects of opioids of abuse, the extent to which they safely alleviate withdrawal and opioid-cravings corresponds with their intrinsic µ opioid receptor (MOR) efficacy. In addition to inhibiting the euphoric effects of opioids of abuse, the medium efficacy MOR agonist buprenorphine alleviates withdrawal and opioid-cravings, but its intrinsic MOR efficacy is sufficient such that its utility is limited by abuse and safety liabilities. Although the MOR antagonist naltrexone minimizes euphoria and has no abuse liability, it exacerbates suffering associated with withdrawal and opioid cravings. Therefore, a therapeutic with intrinsic MOR activity between the partial agonist (buprenorphine) and the antagonist (naltrexone) would strike a balance between the benefits and liabilities of these two therapeutics. To address this need, we derived RM1490, an MOR agonist based on a nonmorphinan scaffold that exhibits approximately half the intrinsic MOR efficacy of buprenorphine. In a series of preclinical assays, we compared RM1490 with buprenorphine and naltrexone at doses that achieve therapeutic levels of central nervous system MOR occupancy. RM1490 exhibited a behavioral profile consistent with reduced reward, dependence, and precipitated withdrawal liabilities. RM1490 was also more effective than buprenorphine at reversing the respiratory depressant effects of fentanyl and did not suppress respiration when combined with diazepam. SIGNIFICANCE STATEMENT: In preclinical studies, RM1490 has a physiological and behavioral profile suitable for opioid use disorder maintenance therapy.

Experimental Drugs for Panic Disorder: An Updated Systematic Review

Several effective pharmacological therapies for panic disorder (PD) are available, but they have some drawbacks, and unsatisfactory outcomes can occur. Expanding the variety of anti-panic medications may allow for improving PD treatment. The authors performed an updated systematic review of preclinical and clinical (Phase I–III) pharmacological studies to look for advances made in the last six years concerning novel-mechanism-based anti-panic compounds or using medications approved for nonpsychiatric medical conditions to treat PD. The study included seven published articles presenting a series of preclinical studies, two Phase I clinical studies with orexin receptor (OXR) antagonists, and two clinical studies investigating the effects of D-cycloserine (DCS) and xenon gas in individuals with PD. The latest preclinical findings confirmed and expanded previous promising indications of OXR1 antagonists as novel-mechanism-based anti-panic compounds. Translating preclinical research into clinical applications remains in the early stages. However, limited clinical findings suggested the selective OXR1 antagonist JNJ-61393115 may exert anti-panic effects in humans. Overall, OXR1 antagonists displayed a favorable profile of short-term safety and tolerability. Very preliminary suggestions of possible anti-panic effects of xenon gas emerged but need confirmation with more rigorous methodology. DCS did not seem promising as an enhancer of cognitive-behavioral therapy in PD. Future studies, including objective panic-related physiological parameters, such as respiratory measures, and expanding the use of panic vulnerability biomarkers, such as hypersensitivity to CO₂ panic provocation, may allow for more reliable conclusions about the anti-panic properties of new compounds.

Comparison and interaction of morphine and CB1 agonist conditioned place preference in the rat model of early life stress

Early life stress (ELS) disrupts brain development and subsequently affects physical and psychological health. ELS has been associated with an increased risk of relapse and inadequate treatment response in addicted patients. The current study was designed to find the effect of ELS on the rewarding effect of morphine and cannabinoid and their interaction. Pregnant female Wistar rats were used in this study. On postnatal day 2 (PND2), pups were separated from their mothers for 3 hr daily. This procedure was repeated every day at the same time until PND 14. The control group was kept in the standard nesting way with their mothers. The adult male offspring of maternal separated (MS) and standard nested (SN) rats were used. Using conditioned place preference task (CPP), the rewarding effect of morphine (0.75, 1.25, 2.5, and 5 mg/kg) was evaluated in both MS and SN groups. Besides, the rewarding effect of cannabinoids was investigated using the administration of CB1 receptor agonist (ACPA, 0.25, 0.5, 1 µg/rat) and inverse agonist (AM-251, 30, 60, and 90 ng/rat) in the nucleus accumbens (NAc). To evaluate the interaction between NAc cannabinoidergic system and morphine, the noneffective dose of ACPA and AM-251 were administered with a noneffective dose of morphine (0.75 mg/kg) on both MS and SN animals. Obtained results indicated that MS groups had a leftward shift in the rewarding effect of morphine and conditioned with low doses of morphine. However, they had a rightward shift in the rewarding effect of cannabinoids. In addition, coadministration of noneffective doses of morphine and ACPA potentiate conditioning in both MS and SN groups. Previous evidence shows that ELS induced changes in the brain, especially in the reward circuits. Here, we demonstrated that MS animals are more sensitive to the rewarding effect of morphine compared with SN animals. In addition, ELS disrupts the cannabinoid system and affect the rewarding effect of cannabinoids.

Neonatal morphine exposure and maternal deprivation alter nociceptive response and central biomarkers' levels throughout the life of rats

In the present study, we investigated the effect of repeated neonatal morphine exposure and/or maternal deprivation(MD) on the nociceptive response and central biomarkers' BDNF, IL-1β, and IL-4 levels at postnatal days 16(PND16), 30(PND30), and 60(PND60). At birth, the litters were standardized to contain 8 pups/dam (n = 58). From PND1 to PND10, the pups of the deprived groups were separated daily from their mothers for 3 h and divided into 5 groups: control(C), saline(S), morphine(M), deprived-saline(DS), and deprived-morphine(DM). The pups received subcutaneous injections of saline/morphine (5 μg) in the mid-scapular area between PND8 and PND14. Nociceptive responses were assessed by hot plate(HP) and tail-flick(TFL) tests and biomarker levels by ELISA. Thermal hyperalgesia(HP) was found in all assessments for the M, DS, and DM groups, and a decrease in nociceptive threshold(TFL) was found in the DS group at PND16; M and DM groups at PND30; and M, DS, and DM groups at PND60. There were interactions between treatment/deprivation/timepoint in all central biomarkers' levels. The current study indicates that neonatal exposure to morphine and MD, which occurs in the pediatric ICU, can alter the nociceptive and neuroinflammatory responses.

A neurobiological framework of separation anxiety and related phenotypes

In the DSM-5, separation anxiety disorder (SAD) is newly classified in the chapter on anxiety, renewing research efforts into its etiology. In this narrative review, we summarize the current literature on the genetic, endocrine, physiological, neural and neuropsychological underpinnings of SAD per se, SAD in the context of panic disorder, separation anxiety symptoms, and related intermediate phenotypes. SAD aggregates in families and has a heritability of ~43%. Variants in the oxytocin receptor, serotonin transporter, opioid receptor µ1, dopamine D4 receptor and translocator protein genes have all been associated with SAD. Dysregulation of the hypothalamus-pituitary-adrenal axis, dysfunctional cortico-limbic interaction and biased cognitive processing seem to constitute further neurobiological markers of separation anxiety. Hypersensitivity to carbon dioxide appears to be an endophenotype shared by SAD, panic disorder and anxiety sensitivity. The identification of biological risk markers and its multi-level integration hold great promise regarding the prediction of SAD risk, maintenance and course, and in the future may allow for the selection of indicated preventive and innovative, personalized therapeutic interventions.

Mental health and psychosocial problems among Chinese left-behind children: A cross-sectional comparative study

BACKGROUND

Separation from migrant parents threatens the mental health of approximately 61 million left-behind children (LBC) in China. This study compared the prevalence of mental health and psychosocial problems between LBC and controls in Sichuan province, China.

METHODS

We randomly recruited LBC and adolescents aged 12-16 years old from 16 rural high schools in 8 counties in Sichuan province. We compared frequency of school bullying, self-esteem, panic symptoms, depression and severe psychological distress(SPD) between LBC and controls from the same schools. These variables were assessed through face-to-face interviews and self-report questionnaires.

RESULTS

The prevalence of mental health problems was 43.4% among LBC(n = 1663) but 30.8% among controls(n = 1683), and the prevalence of specific psychological symptoms was also higher among LBC: SPD, 12.1% vs. 4.8%; panic, 32.4% vs. 22.1%; and depressive symptoms, 26.5% vs. 16.3%. Low self-esteem was more prevalent among LBC(26.6% vs. 18.2%) as was severe school bullying(18.5% vs. 11.3%). Among LBC, low self-esteem was associated with an increased risk of depression or SPD, and school bullying was a significant predictor of depression, panic symptoms and SPD. Low self-esteem and depression increased with longer separation from parents, and this risk was higher when the primary caregivers were LBC themselves or relatives compared to single parents or grandparents.

LIMITATION

LBC misbehavior, such as internet addiction, smoking and drinking, may also explain our findings; these factors need to be explored in future studies.

CONCLUSION

Our results highlight the urgent need for school-based and targeted interventions for LBC to prevent negative mental health outcomes.

Daily maternal separations during stress hyporesponsive period decrease the thresholds of panic-like behaviors to electrical stimulation of the dorsal periaqueductal gray of the adult rat

The present study examined whether early life maternal separation (MS), a model of childhood separation anxiety, predisposes to panic at adulthood. For this purpose, male pups were submitted to 3-h daily maternal separations along postnatal (PN) days of either the 'stress hyporesponsive period' (SHRP) from PN4 to PN14 (MS11) or throughout lactation from PN2 to PN21 (MS20). Pups were further reunited to conscious (CM) or anesthetized (AM) mothers to assess the effect of mother-pup interaction upon reunion. Controls were subjected to brief handling (15 s) once a day throughout lactation (BH20). As adults (PN60), rats were tested for the thresholds to evoke panic-like behaviors upon electrical stimulation of dorsal periaqueductal gray matter and exposed to an elevated plus-maze, an open-field, a forced swim and a sucrose preference test. A factor analysis was also performed to gain insight into the meaning of behavioral tests. MS11-CM rather than MS20-CM rats showed enhanced panic responses and reductions in both swimming and sucrose preference. Panic facilitations were less intense in mother-neglected rats. Although MS did not affect anxiety, MS11-AM showed robust reductions of defecation in an open-field. Factor analysis singled out anxiety, hedonia, exploration, coping and gut activity. Although sucrose preference and coping loaded on separate factors, appetite (adult weight) correlated with active coping in both forced swim and open-field (central area exploration). Concluding, whereas 3h-daily maternal separations during SHRP increased rat's susceptibility to experimental panic attacks, separations throughout lactation had no effects on panic and enhanced active coping.

Effect of single doses of pindolol and d-fenfluramine on flumazenil-induced anxiety in panic disorder patients

The effects of the 5-HT_1A receptor blocker pindolol and the 5-HT releasing and uptake blocking agent d-fenfluramine, both used as indirect serotonin agonists, on flumazenil-induced acute anxiety reactions were studied in panic disorder patients to test the hypothesis that serotonin (5-HT) inhibits neural systems mediating panic attacks. Thirty never treated or drug free PD patients (16 females) aged 22-49 y (mean ± SD, 32.9 ± 8) received single doses of d-fenfluramine (n = 10; 30 mg, p.o.), pindolol (n = 10; 5 mg, p.o.), or placebo (n = 10) 90 and 45 min before a challenge test with flumazenil (1.5 mg, i.v., in 10 min), under double-blind conditions. Panic attacks occurred in 5 control subjects (placebo-flumazenil group), 5 subjects in the pindolol group and in 7 in the d-fenluramine pre-treated patients. Patients experiencing anxiety attacks following flumazenil reported higher increases in anxiety scores. Respiratory rate increases were not different between patients experiencing or not a panic attack. Despite sample size limitation, this study suggests that flumazenil induced anxiety reaction is not a good pharmacological model of panic attacks, considering the absence of serotonergic modulation of its effects.

Experiencing neonatal maternal separation increased pain sensitivity in adult male mice: Involvement of oxytocinergic system

Early-life stress adversely affects the development of the brain, and alters a variety of behaviors such as pain in later life. In present study, we investigated how early-life stress (maternal separation or MS) can affect the nociceptive response later in life. We particularly focused on the role of oxytocin (OT) in regulating nociception in previously exposed (MS during early postnatal development) mice that were subjected to acute stress (restraint stress or RS). Further, we evaluated whether such modulation of pain sensation in MS mice are regulated by shared mechanisms of the OTergic and opioidergic systems. To do this, we assessed the underlying systems mediating the nociceptive response by administrating different antagonists (for both opioid and OTergic systems) under the different experimental conditions (control vs MS, and control plus RS vs MS plus RS). Our results showed that MS increased pain sensitivity in both tail-flick and hot-plate tests while after administration of OT (1μg/μl/mouse, i.c.v) pain threshold was increased. Atosiban, an OT antagonist (10μg/μl/mouse, i.c.v) abolished the effects of OT. While acute RS increased the pain threshold in control (and not MS) mice, treating MS mice with OT normalized the pain response to RS. This latter effect was reversed by atosiban and/or naltrexone, an opioid antagonist (0.5μg/μl/mouse, i.c.v) suggesting that OT enhances the effect of endogenous opioids. OTergic system is involved in mediating the nociception under acute stress in mice subjected to early-life stress and OTergic and opioidergic systems interact to modulate pain sensitivity in MS mice.

The neural circuits of innate fear: detection, integration, action, and memorization

How fear is represented in the brain has generated a lot of research attention, not only because fear increases the chances for survival when appropriately expressed but also because it can lead to anxiety and stress-related disorders when inadequately processed. In this review, we summarize recent progress in the understanding of the neural circuits processing innate fear in rodents. We propose that these circuits are contained within three main functional units in the brain: a detection unit, responsible for gathering sensory information signaling the presence of a threat; an integration unit, responsible for incorporating the various sensory information and recruiting downstream effectors; and an output unit, in charge of initiating appropriate bodily and behavioral responses to the threatful stimulus. In parallel, the experience of innate fear also instructs a learning process leading to the memorization of the fearful event. Interestingly, while the detection, integration, and output units processing acute fear responses to different threats tend to be harbored in distinct brain circuits, memory encoding of these threats seems to rely on a shared learning system.

Experiencing neonatal maternal separation increased the seizure threshold in adult male mice: Involvement of the opioid system

Experiencing early-life stress has been considered as a potent risk factor for the development of many of brain disorders, including seizures. Intervening mechanisms through which neonatal maternal separation (MS) alters the seizure susceptibility in adulthood have not been well studied. In the current study, by applying 180 min of MS stress (PND 2-14), we determined the seizure susceptibility and considered the role of the opioid system. Maternal separation increased the seizure threshold, and administration of anticonvulsant/proconvulsant doses of morphine (1 and 30 mg/kg, respectively) reversed the impact of MS. Using tail flick and hot plate tests, we exposed animals to 30 min Restraint stress (RS) and found that MS decreased the pain threshold, suggesting the hyporesponsiveness of the opioid system. These results supported the abnormal seizure activity observed in the MS mice and suggested that abnormalities in the opioid system following MS alter seizure susceptibility in later life.

Translational approach to studying panic disorder in rats: hits and misses

Panic disorder (PD) patients are specifically sensitive to 5–7% carbon dioxide. Another startling feature of clinical panic is the counterintuitive lack of increments in ‘stress hormones’. PD is also more frequent in women and highly comorbid with childhood separation anxiety (CSA). On the other hand, increasing evidence suggests that panic is mediated at dorsal periaqueductal grey matter (DPAG). In line with prior studies showing that DPAG-evoked panic-like behaviours are attenuated by clinically-effective treatments with panicolytics, we show here that (i) the DPAG harbors a hypoxia-sensitive alarm system, which is activated by hypoxia and potentiated by hypercapnia, (ii) the DPAG suffocation alarm system is inhibited by clinically-effective treatments with panicolytics, (iii) DPAG stimulations do not increase stress hormones in the absence of physical exertion, (iv) DPAG-evoked panic-like behaviours are facilitated in neonatally-isolated adult rats, a model of CSA, and (v) DPAG-evoked responses are enhanced in the late diestrus of female rats. Data are consistent with the DPAG mediation of both respiratory and non-respiratory types of panic attacks.

Lifestyle Behaviours Add to the Armoury of Treatment Options for Panic Disorder: An Evidence-Based Reasoning

This article presents an evidence-based reasoning, focusing on evidence of an Occupational Therapy input to lifestyle behaviour influences on panic disorder that also provides potentially broader application across other mental health problems (MHP). The article begins from the premise that we are all different. It then follows through a sequence of questions, examining incrementally how MHPs are experienced and classified. It analyses the impact of individual sensitivity at different levels of analysis, from genetic and epigenetic individuality, through neurotransmitter and body system sensitivity. Examples are given demonstrating the evidence base behind the logical sequence of investigation. The paper considers the evidence of how everyday routine lifestyle behaviour impacts on occupational function at all levels, and how these behaviours link to individual sensitivity to influence the level of exposure required to elicit symptomatic responses. Occupational Therapists can help patients by adequately assessing individual sensitivity, and through promoting understanding and a sense of control over their own symptoms. It concludes that present clinical guidelines should be expanded to incorporate knowledge of individual sensitivities to environmental exposures and lifestyle behaviours at an early stage.