Hypothalamus-pituitary-adrenal axis of heroin addicts

Iatrogenic adrenal insufficiency in adults

Iatrogenic adrenal insufficiency (IAI) is the most common form of adrenal insufficiency in adult patients, although its overall exact prevalence remains unclear. IAI is associated with adverse clinical outcomes, including adrenal crisis, impaired quality of life and increased mortality; therefore, it is imperative that clinicians maintain a high index of suspicion in patients at risk of IAI to facilitate timely diagnosis and appropriate management. Herein, we review the major causes, clinical consequences, diagnosis and care of patients with IAI. The management of IAI, particularly glucocorticoid-induced (or tertiary) adrenal insufficiency, can be particularly challenging, and the provision of adequate glucocorticoid replacement must be balanced against minimizing the cardiometabolic effects of excess glucocorticoid exposure and optimizing recovery of the hypothalamic-pituitary-adrenal axis. We review current treatment strategies and their limitations and discuss developments in optimizing treatment of IAI. This comprehensive Review aims to aid clinicians in identifying who is at risk of IAI, how to approach screening of at-risk populations and how to treat patients with IAI, with a focus on emergency management and prevention of an adrenal crisis.

The Role of Physical Exercise in Opioid Substitution Therapy: Mechanisms of Sequential Effects

It is generally accepted that chronic opioid use is associated with structural and functional changes in the human brain that lead to an enhancement of impulsive behavior for immediate satisfaction. Interestingly, in recent years, physical exercise interventions have been used as an adjunctive treatment for patients with opioid use disorders (OUDs). Indeed, exercise has positive effects on both the biological and psychosocial basis of addiction, modifying neural circuits such as the reward, inhibition, and stress systems, and thus causing behavioral changes. This review focuses on the possible mechanisms that contribute to the beneficial effects of exercise on the treatment of OUDs, with emphasis placed on the description of a sequential consolidation of these mechanisms. Exercise is thought to act initially as a factor of internal activation and self-regulation and eventually as a factor of commitment. This approach suggests a sequential (temporal) consolidation of the functions of exercise in favor of gradual disengagement from addiction. Particularly, the sequence in which the exercise-induced mechanisms are consolidated follows the pattern of internal activation-self-regulation-commitment, eventually resulting in stimulation of the endocannabinoid and endogenous opioid systems. Additionally, this is accompanied by modification of molecular and behavioral aspects of opioid addiction. Overall, the neurobiological actions of exercise in combination with certain psychological mechanisms appear to promote its beneficial effects. Given the positive effects of exercise on both physical and mental health, exercise prescription is recommended as a complement to conventional therapy for patients on opioid maintenance treatment.

A Closer Look at Opioid-Induced Adrenal Insufficiency: A Narrative Review

Among several opioid-associated endocrinopathies, opioid-associated adrenal insufficiency (OIAI) is both common and not well understood by most clinicians, particularly those outside of endocrine specialization. OIAI is secondary to long-term opioid use and differs from primary adrenal insufficiency. Beyond chronic opioid use, risk factors for OIAI are not well known. OIAI can be diagnosed by a variety of tests, such as the morning cortisol test, but cutoff values are not well established and it is estimated that only about 10% of patients with OIAI will ever be properly diagnosed. This may be dangerous, as OIAI can lead to a potentially life-threatening adrenal crisis. OIAI can be treated and for patients who must continue opioid therapy, it can be clinically managed. OIAI resolves with opioid cessation. Better guidance for diagnosis and treatment is urgently needed, particularly in light of the fact that 5% of the United States population has a prescription for chronic opioid therapy.

The biochemical diagnosis of adrenal insufficiency with modern cortisol assays: Reappraisal in the setting of opioid exposure and hospitalization

OBJECTIVE

We aimed to (1) examine the diagnosis of opioid-induced adrenal insufficiency, and (2) investigate the diagnostic value of a morning cortisol <83 nmol/L (3 µg/dl) for the diagnosis of adrenal insufficiency, using newer more specific cortisol assays and cut-offs.

DESIGN

Retrospective study (5/2015-10/2020).

PARTICIPANTS

Cohort 1 (N = 75): adults who underwent cosyntropin stimulation testing and opioid exposure for >30 days. Cohort 2 (N = 854): adults, with or without opioid exposure, who had a morning cortisol level measured the same day as stimulation testing.

MEASUREMENTS

Peak cortisol during cosyntropin stimulation testing. Sensitivity and specificity of morning serum cortisol for adrenal insufficiency.

RESULTS

The prevalence of adrenal insufficiency in patients with chronic opioid exposure who underwent cosyntropin stimulation testing was 4.0% using a cortisol cutoff of <405 nmol/L (14.7 µg/dl) versus 19% using the traditional cutoff of <500 nmol/L (18.1 µg/dl). For hospitalized patients with and without opioid-exposure, 14 of 22 (64%) patients with morning cortisol levels of <83 nmol/L (3 µg/dl) passed cosyntropin stimulation testing. A morning cortisol level of <348 nmol/L (12.6 µg/dl) had 100% sensitivity (95% confidence interval: 84.5%-100%) for the diagnosis of adrenal insufficiency.

CONCLUSION

Applying a cutoff of <405 nmol/L (14.7 µg/dl), opioid-induced adrenal insufficiency is rare. Nearly 1 out of 6 patients would be reclassified as having adrenal insufficiency applying the guideline-recommended cutoff of <500 nmol/L (18.1 µg/dl). Serum morning cortisol <83 nmol/L (3 µg/dl) is not a valid diagnostic test for adrenal insufficiency in hospitalized patients, whether or not receiving opioids.

Dopamine D1 and D2 receptors are distinctly associated with rest-activity rhythms and drug reward

BACKGROUND

Certain components of rest-activity rhythms such as greater eveningness (delayed phase), physical inactivity (blunted amplitude) and shift work (irregularity) are associated with increased risk for drug use. Dopaminergic (DA) signaling has been hypothesized to mediate the associations, though clinical evidence is lacking.

METHODS

We examined associations between rhythm components and striatal D1 (D1R) and D2/3 receptor (D2/3R) availability in 32 healthy adults (12 female, age: 42.40±12.22) and its relationship to drug reward. Rest-activity rhythms were assessed by one-week actigraphy combined with self-reports. [11C]NNC112 and [11C]raclopride Positron Emission Tomography (PET) scans were conducted to measure D1R and D2/3R availability, respectively. Additionally, self-reported drug-rewarding effects of 60 mg oral methylphenidate were assessed.

RESULTS

We found that delayed rhythm was associated with higher D1R availability in caudate, which was not attributable to sleep loss or 'social jet lag', whereas physical inactivity was associated with higher D2/3R availability in nucleus accumbens (NAc). Delayed rest-activity rhythm, higher caudate D1R and NAc D2/3R availability were associated with greater sensitivity to the rewarding effects of methylphenidate.

CONCLUSION

These findings reveal specific components of rest-activity rhythms associated with striatal D1R, D2/3R availability and drug-rewarding effects. Personalized interventions that target rest-activity rhythms may help prevent and treat substance use disorders.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03190954FUNDING. This work was accomplished with support from the National Institute on Alcohol Abuse and Alcoholism (ZIAAA000550).

Behavioral predictors of individual differences in opioid addiction vulnerability as measured using i.v. self-administration in rats

BACKGROUND

Like other forms of psychopathology, vulnerability to opioid addiction is subject to wide individual differences. Animal behavioral models are valuable in advancing our understanding of mechanisms underlying vulnerability to the disorder's development and amenability to treatment.

METHODS

This review provides an overview of preclinical work on behavioral predictors of opioid addiction vulnerability as measured using the intravenous (i.v.) self-administration (SA) model in rats. We also highlight several new approaches to studying individual differences in opioid addiction vulnerability in preclinical models that could have greater sensitivity and lead to more clinically relevant findings.

RESULTS AND CONCLUSIONS

Evidence for the relationship between various behavioral traits and opioid SA in the preclinical literature is limited. With the possible exceptions of sensitivity to opioid agonist/withdrawal effects and stress reactivity, predictors of individual differences in SA of other drugs of abuse (e.g. sensation-seeking, impulsivity) do not predict vulnerability to opioid SA in rats. Refinement of SA measures and the use of multivariate designs and statistics could help identify predictors of opioid SA and lead to more clinically relevant studies on opioid addiction vulnerability.

Circadian rhythms and substance use disorders: A bidirectional relationship

The circadian system organizes circadian rhythms (biological cycles that occur around 24 h) that couple environmental cues (zeitgebers) with internal functions of the organism. The misalignment between circadian rhythms and external cues is known as chronodisruption and contributes to the development of mental, metabolic and other disorders, including cancer, cardiovascular diseases and addictive disorders. Drug addiction represents a global public health concern and affects the health and well-being of individuals, families and communities. In this manuscript, we reviewed evidence indicating a bidirectional relationship between the circadian system and the development of addictive disorders. We provide information on the interaction between the circadian system and drug addiction for each drug or drug class (alcohol, cannabis, hallucinogens, psychostimulants and opioids). We also describe evidence showing that drug use follows a circadian pattern, which changes with the progression of addiction. Furthermore, clock gene expression is also altered during the development of drug addiction in many brain areas related to drug reward, drug seeking and relapse. The regulation of the glutamatergic and dopaminergic neurocircuitry by clock genes is postulated to be the main circadian mechanism underlying the escalation of drug addiction. The bidirectional interaction between the circadian system and drug addiction seems to be mediated by the effects caused by each drug or class of drugs of abuse. These studies provide new insights on the development of successful strategies aimed at restoring/stabilizing circadian rhythms to reduce the risk for addiction development and relapse.

Craving in Opioid Use Disorder: From Neurobiology to Clinical Practice

Opioid use disorder (OUD) is a major public health issue that has reached epidemic levels in some parts of the world. It is a chronic and complex neurobiological disease associated with frequent relapse to drug taking. Craving, defined as an overwhelmingly strong desire or need to use a drug, is a central component of OUD and other substance use disorders. In this review, we describe the neurobiological and neuroendocrine pathways that underpin craving in OUD and also focus on the importance of assessing and treating craving in clinical practice. Craving is strongly associated with patients returning to opioid misuse and is therefore an important treatment target to reduce the risk of relapse and improve patients' quality of life. Opioid agonist therapies (OAT), such as buprenorphine and methadone, can significantly reduce craving and relapse risk, and it is essential that patients are treated optimally with these therapies. There is also evidence to support the benefits of non-pharmacological approaches, such as cognitive behavioral therapy and mindfulness-based interventions, as supplementary treatments to opioid agonist therapies. However, despite the positive impact of these treatments on craving, many OUD patients continue to suffer with negative affect and dysphoria. There is a clear need for further studies to progress our understanding of the neurobiological basis of craving and addiction and to identify novel therapeutic strategies as well as to optimize the use of existing treatments to improve outcomes for the growing numbers of patients affected by OUD.

MECHANISMS OF ENDOCRINOLOGY: Endocrinology of opioids

The use of opioids has grown substantially over the past two decades reaching the dimensions of a global epidemic. These drugs have effects on multiple levels of the endocrine system through mechanisms which are still not fully elucidated, and awareness of their endocrine sequelae is vital for all specialists prescribing or managing patients on them. Hypogonadism is the most well-recognised consequence of opioid use (prevalence 21–86%) which, however, may remain undiagnosed with potential adverse outcomes for the patients. Although less frequent, cortisol deficiency can also be found. Furthermore, there is a negative impact on bone health (with reduced bone mineral density and increased fracture risk) and occasionally hyperprolactinaemia, whereas the clinical significance of alterations in other hormones remains to be clarified. Discontinuation or reduction of the opioid and, in cases of chronic pain, consideration of alternative therapies for pain relief are potential management options. Hormonal replacement, especially when the above measures are not practically feasible, needs to be considered. Further studies are needed to clearly establish the prevalence of hormonal abnormalities with various regimes, doses and routes of opioids and to address reliably the long-term benefits and risks of hormonal treatment in patients on opioids. Until evidence-based, safe and cost-effective clinical guidelines become available, periodical assessment of the gonadal and adrenal function (particularly when relevant clinical manifestations are present) and evaluation of the bone health status are advised.

Racing the clock: The role of circadian rhythmicity in addiction across the lifespan

Although potent effects of psychoactive drugs on circadian rhythms were first described over 30 years ago, research into the reciprocal relationship between the reward system and the circadian system - and the impact of this relationship on addiction - has only become a focus in the last decade. Nonetheless, great progress has been made in that short time toward understanding how drugs of abuse impact the molecular and physiological circadian clocks, as well as how disruption of normal circadian rhythm biology may contribute to addiction and ameliorate the efficacy of treatments for addiction. In particular, data have emerged demonstrating that disrupted circadian rhythms, such as those observed in shift workers and adolescents, increase susceptibility to addiction. Furthermore, circadian rhythms and addiction impact one another longitudinally - specifically from adolescence to the elderly. In this review, the current understanding of how the circadian clock interacts with substances of abuse within the context of age-dependent changes in rhythmicity, including the potential existence of a drug-sensitive clock, the correlation between chronotype and addiction vulnerability, and the importance of rhythmicity in the mesocorticolimbic dopamine system, is discussed. The primary focus is on alcohol addiction, as the preponderance of research is in this area, with references to other addictions as warranted. The implications of clock-drug interactions for the treatment of addiction will also be reviewed, and the potential of therapeutics that reset the circadian rhythm will be highlighted.

Adrenal insufficiency in patients on long-term opioid analgesia

OBJECTIVE

Opioid analgesia has been implicated as a cause of secondary adrenal insufficiency, but little is known of the prevalence of this potentially serious adverse effect in patients with chronic pain.

DESIGN

Cross-sectional study of chronic pain patients on long-term opioid analgesia.

PATIENTS

Patients attending tertiary chronic pain clinics at the Western General Hospital, Edinburgh, treated with long-term opioid analgesia (n = 48) with no recent exposure to exogenous glucocorticoids.

RESULTS

Four patients (8·3%) had basal morning plasma cortisol concentrations below 100 nmol/l, of whom three failed to achieve a satisfactory cortisol response to exogenous ACTH_1-24 stimulation (peak cortisol >430 nmol/l). Basal cortisol was positively associated with age (R = 0·398, P = 0·005) and negatively associated with BMI (R = -0·435, P = 0·002).

CONCLUSIONS

Suppression of the hypothalamic-pituitary-adrenal axis is present in a clinically significant proportion of chronic pain patients treated with opioid analgesia. Studies of larger populations should be conducted to better define the prevalence and potential clinical consequences of adrenal insufficiency in this context.

Loperamide-induced hypopituitarism

Loperamide is the most commonly used antidiarrhoeal medication in the UK. We report a serious and hitherto undocumented adverse effect of chronic use in a 45-year-old man with inflammatory bowel disease. He presented to the endocrine clinic with fatigue and low libido; biochemical assessment revealed hypogonadism and adrenal insufficiency without any elevated adrenocorticotropic hormone. When symptoms allowed, loperamide was reduced and a short synacthen test (SST) showed a ‘clear pass’ with a normal peak cortisol of 833 nmol/L. Later, worsening diarrhoea necessitated an escalation in loperamide use again. While taking a daily dose of 15–20 mg (recommended daily maximum 16 mg) reassessment revealed a fall in peak cortisol on SST to 483 nmol/L, a subnormal response. Clinicians should exercise caution when relying on loperamide to manage their patients’ chronic diarrhoea and remain mindful of the possibility of drug-induced life-threatening adrenal insufficiency.

Elevated Hair Cortisol Levels among Heroin Addicts on Current Methadone Maintenance Compared to Controls

Whether methadone maintenance treatment (MMT) can improve the basal function of the hypothalamic–pituitary–adrenal (HPA) axis, which is suppressed by long-term heroin consumption, is a matter of debate. The stress state and depression and anxiety symptoms may affect the basal activity of the HPA axis in MMT patients. However, the effect of psychological factors on HPA activity was not simultaneously controlled in previous studies. This study investigated differences in HPA basal activity between MMT patients and controls using psychological variables as covariates. The participants included 52 MMT patients and 41 age-matched, non-heroin-dependent controls. Psychological states were self-reported with the Perceived Stress Scale, Self-Rating Depression Scale and Self-Rating Anxiety Scale. The hair cortisol level was adopted as a biomarker of HPA basal activity and was determined with liquid chromatography tandem mass spectrometry. The results revealed that MMT patients had significantly higher hair cortisol levels than the controls (p<0.05), but the difference was not significant (p>0.05) when the perceived stress, depression and anxiety scores were used as covariates. We concluded that patients with long-term MMT showed higher basal activity of the HPA axis. The high chronic stress state and increase in depression and anxiety symptoms may mask the suppression effect of methadone on the HPA activity.

The relationship between alcohol consumption, perceived stress, and CRHR1 genotype on the hypothalamic-pituitary-adrenal axis in rural African Americans

OBJECTIVE

Rurally situated African Americans suffer from stress and drug-related health disparities. Unfortunately, research on potential mechanisms that underlie this public health problem have received limited focus in the scientific literature. This study investigated the effects of perceived stress, alcohol consumption, and genotype on the hypothalamic-pituitary-adrenal (HPA) Axis.

METHODS

A rural sample of African American emerging adults (n = 84) completed a battery of assessments and provided six samples of salivary cortisol at wakeup, 30 min post wakeup, 90 min post wakeup, 3:00 PM, 3:30 PM, and 4:30 PM.

RESULTS

Participants with a TT genotype of the CRHR1 (rs4792887) gene tended to produce the most basal cortisol throughout the day while participants with a CC genotype produced the least amount. Increased levels of perceived stress or alcohol consumption were associated with a blunted cortisol awakening response (CAR). Moreover, the CAR was obliterated for participants who reported both higher stress and alcohol consumption.

CONCLUSION

Perceived stress and alcohol consumption had a deleterious effect on the HPA-Axis. Furthermore, genotype predicted level of cortisol production throughout the day. These findings support the need to further investigate the relationship between stress dysregulation, drug-use vulnerability, and associated health disparities that affect this community.

Psychological and physiological stress negatively impacts early engagement and retention of opioid-dependent individuals on methadone maintenance

The present study investigated whether psychological and/or physiological measures of stress would impede induction onto methadone maintenance and predict early (<6 months) discontinuation. Compared with controls, opioid-dependent subjects displayed increased distress on the perceived stress scale (PSS) and post-traumatic stress disorder checklist (PCLC); 60% exhibited abnormal cortisol. Addiction severity index (ASI), drug-use, and stress indices explained between 17 and 37% of the variance in engagement including attendance, opioid abstinence, and methadone stabilization. Participants who discontinued treatment displayed poor engagement, abnormal cortisol, elevated withdrawal symptoms, higher distress, and increased ongoing opioid use versus compliant individuals. Discontinuation was initially related to drug-use severity; however, by 6 months, retention depended primarily upon cortisol abnormalities, which increased an individual's discontinuation risk by 7.7-fold. These findings support admission screening with the ASI/cortisol for drop out, and stress/drug-use indices for engagement that together may enable clinically-relevant early recognition and interventions for prevention of stress-induced relapse in opioid-dependent populations.

Opioid-induced endocrinopathy in cancer patients: an underestimated clinical problem

The impact of both endogenous and exogenous opioids on the endocrine system has been known for many years. With the increased use of opioids in chronic pain treatment, the research focuses mainly on their effects on the endocrine system in patients with chronic non-malignant pain. Despite the wide dissemination of cancer, there has been little research on the possible effects of opioids on the endocrine system in cancer patients. For the growing number of cancer survivors and patients in long-term remission who take opioids, other aspects of endocrine disorders caused or exacerbated by opioids will have practical and clinical importance. Conversely, this problem may be less relevant for patients in active cancer treatment or in the advanced stage of disease. This article presents the available research on the effects of opioids on the endocrine system and the clinical consequences resulting from opioid use in cancer patients. Clinicians who use opioids in clinical practice should be aware of the existence of the endocrine symptoms of opioid therapy. There is still a need for more research in this area to maintain the best possible quality of life for cancer patients treated with opioid analgesics.

Atrial natriuretic peptide, arginine vasopressin peptide and cortisol serum levels in opiate-dependent patients

Preclinical studies suggest that chronic drug abuse profoundly alters stress-responsive systems. The best studied of the stress-responsive systems in humans is the hypothalamic-pituitary-adrenal (HPA) axis. Apart from cortisol, arginine vasopressin peptide (AVP), and atrial natriuretic peptide (ANP) are known to directly impact upon the HPA axis in addictive behavior. We investigated alterations in ANP, AVP and cortisol serum levels in opiate-dependent patients who received diacetylmorphine treatment within a structured opiate maintenance program. ANP serum levels were significantly increased in opiate-dependent patients as compared to healthy controls, whereas AVP and cortisol serum levels were reduced. The ANP, AVP and cortisol serum levels were not significantly associated with the psychometric dimensions of heroin craving. In conclusion, chronic drug abuse profoundly alters stress-responsive systems like the HPA axis. Alterations of AVP, ANP and cortisol appear to constitute an important component in the neurobiology of opiate-dependent patients.

A case of hypogonadotropic hypogonadism caused by opioid treatment for nonmalignant chronic pain

We report a case of 42-year-old male patient with hypogonadotropic hypogonadism. He suffered from general fatigue and erectile dysfunction after the treatment with transdermal fentanyl for chronic pain by traffic injury. Endocrine examinations and hormone stimulating tests showed that he had hypogonadotropic hypogonadism. Brain magnetic resonance imaging (MRI) showed no abnormal findings, and he had no past history of accounting for acquired hypogonadotropic hypogonadism. Therefore, his hypogonadism was diagnosed to be caused by opioid treatment. Although opioid-induced endocrine dysfunctions are not widely recognized, this case suggests that we should consider the possibility of endocrine dysfunctions in patients with opioid treatment.

The impact of diacetylmorphine on hypothalamic-pituitary-adrenal axis activity and heroin craving in heroin dependence

BACKGROUND/AIM

Heroin dependence is a chronic relapsing disorder characterized by the compulsion to seek and use heroin. Stress and craving are seen as key factors for heroin use. Moreover, altered hypothalamic-pituitary-adrenal (HPA) axis function has been frequently reported. However, the acute effects of diacetylmorphine (DAM) on HPA axis activity and craving have not been investigated in a controlled study. The present randomized controlled study examined whether DAM administration differs from placebo (saline) administration with regard to HPA axis response and heroin craving.

METHODS

In a crossover experiment, 28 DAM-maintained heroin-dependent patients were first injected with DAM and then saline, or the converse. Plasma adrenocorticotropic hormone (ACTH) and cortisol in saliva and serum were measured at baseline and 20 and 60 min after both injections. Heroin craving was measured at baseline and 60 min after both injections, by means of the Heroin Craving Questionnaire.

RESULTS

Compared to saline, DAM administration induced a significant decrease in plasma ACTH (p < 0.01), serum cortisol (p < 0.0001) and saliva cortisol (p < 0.01), as well as in craving (p < 0.0001), over time.

CONCLUSION

Since acute DAM administration suppresses the stress response, DAM-assisted treatment may be an effective alternative to methadone maintenance in stress-sensitive heroin-dependent patients.

Cue-induced reactivity, cortisol response and substance use outcome in treated heroin dependent individuals

BACKGROUND

Environmental stimuli associated with drug taking have been known to elicit drug craving and physiologic arousal, as well as hypothalamic-pituitary-adrenal axis activation. However, the relationship between these responses and substance use outcomes in heroin-dependent subjects has not been previously studied. We investigated the relationship among subjective and physiologic reactivity, biological stress response evoked in the laboratory, and relapse to substance use in treated opiate-dependent individuals.

METHODS

Eighteen opiate-abstinent methadone- or buprenorphine-treated patients and 13 control subjects were exposed to neutral- and drug-cue exposure laboratory sessions with a 3-month follow-up period. Exposure to cues involved both videotapes and handling during a 100-min session. Subjective craving, agonistic effects, withdrawal feelings, galvanic skin resistance, and salivary cortisol were assessed. Substance use outcome among patients was examined during the follow-up phase. Differences between relapsers, nonrelapsers, and controls were analyzed with respect to the data on drug-cue responsivity and on cortisol responses using repeated-measures analysis of variance. The association with substance use outcome was assessed using a nominal logistic model.

RESULTS

Relapsers experienced greater drug-cue induced subjective responses and an increased cortisol response compared with both nonrelapsers and control subjects. After adjusting on covariates, cue-induced cortisol response was associated with the relapser group and was highly correlated with self-reports of "high."

CONCLUSIONS

Subjects defined as relapsers presented a higher cue-induced reactivity during the drug-cue exposure as well as an increased cortisol response to drug cues. Higher cortisol response to drug cues may increase relapse vulnerability in stable-dose buprenorphine or methadone-maintained subjects.

Differential patterns of HPA activity and reactivity in adult posttraumatic stress disorder and major depressive disorder

Despite a number of overlapping symptoms, individuals with posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) often display hypothalamic-pituitary-adrenal (HPA) profiles that appear quite different from one another. This review describes the patterns of HPA-axis activity and reactivity in healthy individuals compared to individuals with these two disorders. Measures of HPA-axis activity and reactivity include cortisol levels at rest, in response to the dexamethasone suppression test (DST), and in response to psychological stress. The research reviewed presents the possibility of diagnostic specificity with regard to HPA function. In particular, the differential response pattern to the DST suggests that, while it cannot be considered a pure diagnostic tool, it should be one measure taken into consideration during diagnosis.

The impact of opioids on the endocrine system

OBJECTIVES

Opioids have been used for medicinal and analgesic purposes for centuries. However, their negative effects on the endocrine system, which have been known for some times, are barely discussed in modern medicine. Therefore, we conducted a systematic review of the impact of opioids on the endocrine system.

METHODS

A review of the English language literature on preclinical and clinical studies of any type on the influence of opioids on the endocrine system was conducted. Preliminary recommendations for monitoring and managing these problems were provided.

RESULTS

Long-term opioid therapy for either addiction or chronic pain often induces hypogonadism owing to central suppression of hypothalamic secretion of gonadotropin-releasing hormone. Symptoms of opioid-induced hypogonadism include loss of libido, infertility, fatigue, depression, anxiety, loss of muscle strength and mass, osteoporosis, and compression fractures in both men and women; impotence in men; and menstrual irregularities and galactorrhea in women. In view of the increased use of opioids for chronic pain, it has become increasingly important to monitor patients taking opioids and manage endocrine complications. Therefore, patients on opioid therapy should be routinely screened for such symptoms and for laboratory abnormalities in sex hormones.

CONCLUSIONS

Opioid-induced hypogonadism seems to be a common complication of therapeutic or illicit opioid use. Patients on long-term opioid therapy should be prospectively monitored, and in cases of opioid-induced hypogonadism, we recommend nonopioid pain management, opioid rotation, or sex hormone supplementation after careful consideration of the risks and benefits.

Chronic stress, drug use, and vulnerability to addiction

Stress is a well-known risk factor in the development of addiction and in addiction relapse vulnerability. A series of population-based and epidemiological studies have identified specific stressors and individual-level variables that are predictive of substance use and abuse. Preclinical research also shows that stress exposure enhances drug self-administration and reinstates drug seeking in drug-experienced animals. The deleterious effects of early life stress, child maltreatment, and accumulated adversity on alterations in the corticotropin releasing factor and hypothalamic-pituitary-adrenal axis (CRF/HPA), the extrahypothalamic CRF, the autonomic arousal, and the central noradrenergic systems are also presented. The effects of these alterations on the corticostriatal-limbic motivational, learning, and adaptation systems that include mesolimbic dopamine, glutamate, and gamma-amino-butyric acid (GABA) pathways are discussed as the underlying pathophysiology associated with stress-related risk of addiction. The effects of regular and chronic drug use on alterations in these stress and motivational systems are also reviewed, with specific attention to the impact of these adaptations on stress regulation, impulse control, and perpetuation of compulsive drug seeking and relapse susceptibility. Finally, research gaps in furthering our understanding of the association between stress and addiction are presented, with the hope that addressing these unanswered questions will significantly influence new prevention and treatment strategies to address vulnerability to addiction.

Drugs and HPA axis

This paper outlines the interferences of the most widely used drugs with hypothalamo-pituitary-adrenal function and the related laboratory parameters, with the purpose of providing practical help to clinicians during testing for hypo- or hypercortisolemic states.

Association of the 54-nucleotide repeat polymorphism of hPer3 with heroin dependence in Han Chinese population

Circadian clock genes have the function of producing circadian rhythm. They are also implicated in the origin or development of many diseases such as cancers and neuropsychiatric diseases. The purpose of this study is to determine whether the 54-nucleotide repeat polymorphism of hPer3, one of the circadian clock genes, associates with heroin dependence. DNA samples were obtained from 209 Chinese heroin-dependent subjects and 249 Chinese healthy controls. The 54-nucleotide repeat polymorphism was detected by polymerase chain reaction and DNA agarose gel electrophoresis. The frequency of four-repeat allele was significantly higher (chi(2)= 10.64, P = 0.001; corrected for multiple tests, P = 0.003) in the mixed gender heroin-dependent subject group (four repeat: 0.89, five repeat: 0.11) than in the mixed gender control group (four repeat: 0.81, five repeat: 0.19); the frequency of four-repeat allele was also significantly higher (chi(2)= 10.00, P = 0.002; corrected for multiple tests, P = 0.006) in the male heroin-dependent subject group (four repeat: 0.89, five repeat: 0.11) than in the male control group (four repeat: 0.81, five repeat: 0.19); for females, no significant trend was observed with the 54-nucleotide repeat polymorphism between the heroin-dependent subject group and the control group. Our results suggest that the 54-nucleotide repeat polymorphism of hPer3 significantly associates with heroin dependence at the allele frequency level and may be a potential risk factor for the development of heroin dependence.

Disruption of the CRF/CRF1 Receptor Stress System Exacerbates the Somatic Signs of Opiate Withdrawal

Escape from the extremely stressful opiate withdrawal syndrome may motivate opiate seeking and taking. The corticotropin-releasing factor receptor-1 (CRF1) pathway mediates behavioral and endocrine responses to stress. Here, we report that genetic inactivation (CRF1-/-) as well as pharmacological antagonism of the CRF/CRF1 receptor pathway increased and prolonged the somatic expression of opiate withdrawal. Opiate-withdrawn CRF1-/- mice also showed aberrant CRF and dynorphin expression in the paraventricular nucleus of the hypothalamus (PVN) and the striatum, indicating profound impairments in stress-responsive brain circuitry. Intake of nonstressful amounts of corticosterone effectively reduced the exaggerated somatic reactions of CRF1-/- mice to opiate withdrawal. Exogenous corticosterone also restored "wild-type-like" patterns of CRF and dynorphin gene expression in the PVN and the striatum of opiate-withdrawn CRF1-/- mice, respectively. The present findings unravel a key role for the hypothalamus-pituitary-adrenal (HPA) system and brain extra-hypothalamic CRF/CRF1 receptor circuitry in somatic, molecular, and endocrine alterations induced by opiate withdrawal.

Unlimited access to heroin self-administration: independent motivational markers of opiate dependence

The goal of the present study was to develop and validate an animal model of unlimited access to intravenous heroin self-administration combined with responding for food and water to characterize the transition to drug dependence. Male Wistar rats were allowed to lever press for heroin (60 microg/kg/0.1 ml infusion/s; fixed ratio 1; 20-s time out) and nosepoke for food and water in consecutive, daily 23-h sessions. Daily heroin intake increased over days, reaching significance by Day 14. Drug-taking increased across the circadian cycle, reflected as increases in both the nocturnal peak and diurnal nadir of heroin intake. Changes in the circadian pattern of food intake and meal patterning preceded and paralleled the changes in heroin intake. By Day 7, the circadian amplitude of feeding was blunted. Nocturnal intake decreased because rats consumed smaller and briefer meals. Diurnal intake increased due to increased meal frequency, whereas total daily food intake decreased. To control for time or experience in the self-administration boxes as a possible confound, rats with saline (no drug) tethers were tested and did not display significant changes in food intake pattern. Body weight gain slowed slightly in heroin rats relative to saline controls. Separate groups of rats revealed that significant physical dependence as measured by physical signs of opiate withdrawal following a naloxone injection (1.0 mg/kg, subcutaneous (s.c.)) was reached by Day 14. Significant increases in heroin intake could be produced using low doses of naloxone (0.003-0.03 mg/kg, s.c.) on days 28-31 of heroin access. After 6 weeks of heroin self-administration, rats injected with buprenorphine (0, 0.01, 0.04, and 0.2 mg/kg, s.c.) showed a dose-dependent reduction in heroin intake. Changes in the pattern of drug and food intake in the present unlimited heroin access model may serve as independent motivational markers for the transition to a drug-dependent state.

Morphine withdrawal modifies antinociceptive effects of acute morphine in rats

Repeated opioid use is known to cause tolerance of antinociceptive effects. Whether opioid abstinence modifies antinociceptive effects is unknown. Here we reported that morphine withdrawal for 18 h and 4 days after repeated morphine treatment largely reduced tail-flick latencies compared with control, while the rats showed severe withdrawal syndromes. However, the latencies and withdrawal syndromes were restored to control level at 20 days withdrawal. Similarly, antinociceptive effects of acute morphine were decreased at 18 h and further decreased at 4 days but restored to control level at 20 days withdrawal. Behavioral stress that was given to the rats at 18 h withdrawal further reduced tail-flick latencies and antinociceptive effects. Conversely, the glucocorticoid receptor antagonist RU38486 increased tail-flick latencies and antinociceptive effects at 4 days withdrawal. These results suggest that morphine withdrawal could evoke behavioral stress to modify antinociceptive effects, implicating a significant influence of opioid abstinence on chronic pain treatment.

Salivary cortisol during opiate dependence and withdrawal

Seventeen inpatients (14 men, three women) with opiate dependence and polysubstance misuse participated in a longitudinal study of salivary cortisol secretion during and after lofexidine detoxification treatment. Both opiate withdrawal symptoms and salivary cortisol were measured every morning for up to 25 days. Results were compared with a control group of 10 normal volunteers. There was an 80% reduction in withdrawal symptom severity between the first 12 days and the subsequent 12 days of treatment. Salivary cortisol fell from a mean of 22.3 nm/l over days 1-12 to 18.5 nm/l during days 13-25, a reduction of 17%. Salivary cortisol concentration correlated significantly with withdrawal symptom severity. Salivary cortisol levels remained significantly higher than controls for the duration of the study. The study supports a role for hypothalamo-pituitary-adrenal (HPA) activation in opiate withdrawal. The contribution of persistant dysregulation of the HPA, found in this study, to the vulnerability for relapse after abstinence has been achieved, is discussed.

Endocrine consequences of long-term intrathecal administration of opioids

Intrathecal administration of opioids is a very efficient tool in the long-term control of intractable nonmalignant pain. However, despite the well known role of opioids in endocrine regulation, few data are available about possible effects on hypothalamic-pituitary function during this treatment. Seventy-three patients (29 men and 44 women; mean age, 49.2 +/- 11.7 yr) receiving opioids intrathecally for nonmalignant pain were enrolled for extensive endocrine investigation. At the time of hormonal determination, the mean duration of opioid treatment was 26.6 +/- 16.3 months; the mean daily dose of morphine was 4.8 +/- 3.2 mg. The control group consisted of 20 patients (11 men and 9 women; mean age, 54.2 +/- 14.0 yr) with a comparable pain syndrome but not treated with opioids. Decreased libido or impotency was present in 23 of 24 men receiving opioids. The serum testosterone level was below 9 nmol/L in 25 of 29 men and was significantly lower than that in the control group (P < 0.001). The free androgen index was below normal in 18 of 29 men and was significantly lower than that in the control group (P < 0.001). The serum LH level was less than 2 U/L in 20 of 29 men and was significantly lower than that in the control group (P < 0.001). Serum FSH was comparable in both groups. Decreased libido was present in 22 of 32 women receiving opioids. All 21 premenopausal females developed either amenorrhea or an irregular menstrual cycle, with ovulation in only 1. Serum LH, estradiol, and progesterone levels were lower in the opioid group. In all 18 postmenopausal females significantly decreased serum LH (P < 0.001) and FSH (P = 0.012) levels were found. The 24-h urinary free cortisol excretion was below 20 microg/day in 14 of 71 opioid patients and was significantly lower than that in the control group (P = 0.003). The peak cortisol response to insulin-induced hypoglycemia was below 180 microg/L in 9 of 61 opioid patients and was significantly lower than that in the nonopioid group (P = 0.002). The insulin-like growth factor I SD score was below -2 SD in 12 of 73 opioid patients and was significantly lower than that in the control group (P = 0.002). The peak GH response to hypoglycemia was below 3 microg/L in 9 of 62 subjects and was significantly lower than that in the control group (P = 0.010). Thyroid function tests and PRL levels were considered normal. No metabolic disturbances were recorded, apart from significantly decreased high density lipoprotein cholesterol levels (P = 0.041) and elevated total/high density lipoprotein cholesterol ratio (P = 0.008) in the opioid group compared to the control group. Supplementation with gonadal steroids improved sexual function in most patients. In conclusion, of all patients receiving intrathecal opioids, the large majority of men and all women developed hypogonadotropic hypogonadism, about 15% developed central hypocorticism, and about 15% developed GH deficiency. These findings suggest that further investigations are required to determine the need for systematic endocrine work-up in these patients and the necessity for substitutive therapy.

Hypercortisolism after opioid discontinuation in rapid detoxification of heroin addicts

Long-term opioid consumption can induce hypoadrenalism through impairment of the hypothalamic-pituitary-adrenal axis. Results of the present study showed that, in heroin addicts, saliva cortisol concentrations varied according to the amount of recently consumed heroin and the time elapsed since the last self-administration. Hypercortisolism was observed either after abrupt withdrawal of heroin or the last dose of methadone. Post-detoxification hypercortisolism was still present on day 16 after the last opioid consumption, whereas it was not observed in abstinent addicts for a mean period of 4 months. During detoxification treatment, mean AUC8-24 cortisol in saliva of clonidine or guanfacine-treated patients was significantly higher than that in methadone-treated patients. It may be hypothesized that elevated cortisol levels may account for untoward effects of adrenergic agonist therapy which, in turn, may represent an added risk factor for relapse during detoxification. Further studies are necessary to correlate the severity of withdrawal symptoms to cortisol levels in opioid addicts detoxified with alpha 2-adrenergic agonist substitution.

Abnormal adrenal gland metabolism in opioid addicts: implications for clinical treatment

Adrenal gland metabolism is markedly altered in heroin addicts. During daytime hours, the addict may suffer corticoid deficiency of the addisonian type, and in the evening, an excess of the cushingoid type. The high plasma levels of cortisol that are found in the evening in addicts antagonize endogenous opioids in a manner similar to naloxone. In the present study, 72% of the heroin addicts who sought treatment demonstrated reduced adrenal cortisol reserve. Effective immune and stress responses are dependent on adrenal cortisol reserve. This finding provides an explanation for the heroin addict's vulnerability to AIDS and other infectious diseases. One of methadone's greatest attributes is that it helps normalize adrenal metabolism. Clinical methods to at least partially correct adrenal metabolism may enhance current opioid addiction treatment modalities.