Altered functional connectivity of the nucleus accumbens subdivisions in amphetamine-type stimulant abusers: a resting-state fMRI study.

BACKGROUND: The growing abuse of amphetamine-type stimulants leads to new challenges to human health. A possible addiction mechanism has been proposed by altered functional architecture of the nucleus accumbens (NAc) during resting state. NAc contains different subdivisions and they may play different roles in addiction. The aim of the present study was to examine whether there are common or distinct patterns of functional connectivity of the NAc subdivisions in amphetamine-type stimulant abusers (ATSAs). METHODS: The present study recruited 17 male ATSAs and 22 healthy male controls. All the subjects underwent resting-state functional magnetic resonance imaging (fMRI) with their eyes closed. The NAc was divided into core-like and shell-like subdivisions. We used seed-based resting-state functional connectivity (RSFC) analyses to identify differences in brain functional architecture between ATSAs and healthy controls (HCs). RESULTS: ATSAs had lower positive RSFCs with all of the NAc subdivisions over the left orbital part of superior frontal gyrus and higher positive RSFCs with the NAc subdivisions over the left opercular part of inferior frontal gyrus than HCs, which indicates common abnormalities across the NAc subdivisions in ATSAs. In addition, the RSFCs between the NAc subdivisions and the left orbital part of superior frontal gyrus were negatively correlated with the addiction severity in ATSAs. CONCLUSION: These results provide evidence that there are common RSFC patterns of the NAc subdivisions in ATSAs. The abnormality indicated by disrupted functional connectivity between the NAc subdivisions and prefrontal cortex suggests abnormal interaction between the rewarding process and cognitive control in ATSAs. Our results shed insight on the neurobiological mechanisms of ATSA and suggest potential novel therapeutic targets for treatment and intervention of ATSAs.

Nocturnal sleep architecture disturbances in early methadone treatment patients.

The subjective and objective sleep patterns of patients with opioid dependence have been previously reported, but the sleep characteristics of patients in early methadone treatment, especially the objective sleep patterns, remain largely unexamined. This study was designed to explore the nocturnal sleep structure of patients on early methadone treatment. Twenty male methadone treatment (MT) patients and 20 male age- and body mass index-matched controls were assessed with overnight limited polysomnography. Subjective sleep was assessed using the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS). Compared with healthy controls, MT patients had lower sleep efficiency, shorter total sleep time, more awakenings and shorter slow wave sleep (SWS). The PSQI and ESS scores in MT patients were significantly higher than in the controls. ESS scores of the patients were significantly associated with the SWS. The findings indicate that patients in early MT have poor sleep quality and abnormal sleep architecture.

Alterations in pituitary-thyroid axis function among opioid-dependent subjects after acute and protracted abstinence.

The aim of the present study was to investigate the changes in the pituitary-thyroid axis (PTA) and the time course of the hormonal alterations in subjects with opioid dependence after abstinence. Blood samples from in-patients with opioid dependence and age- and sex-matched healthy controls were collected. The severity of opioid abuse and of withdrawal symptoms was assessed. Results were compared between patients with opioid dependence (n = 30) and healthy controls (n = 30). We found that free triiodothyronine and free thyroxine levels were comparable with healthy controls while thyroid-stimulating hormone (TSH) was lower in patients in acute opioid abstinence period. Also, TSH levels in patients remained lower than controls after 30 days of abstinence. These results indicate that PTA function is altered in opioid-dependent subjects. These data highlight the importance of screening the thyroid function for individuals with chronic opioid dependence.

Dysfunction of the hypothalamic-pituitary-adrenal axis in opioid dependent subjects: effects of acute and protracted abstinence.

OBJECTIVES: The function of the Hypothalamic-Pituitary-Adrenal (HPA) axis during opioid dependence has been inconsistent. We compared HPA axis measures between subjects during methadone stabilization and drug-free detoxification with healthy controls. METHODS: Sixty heroin dependent patients received either non-opiate treatment (NOT) with benzodiazepines and clonidine (n = 30) or methadone stabilization treatment (MT, n = 30), and their serum levels of corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and cortisol (COR) were measured and compared to those of healthy, nondependent controls. RESULTS: Compared with healthy controls, CRH was significantly lower (p < .001) while COR was higher (p < .001) during acute withdrawal in the NOT group. CRH and COR was lower (p < .001), while ACTH was normal in the MT group compared to healthy controls. CONCLUSIONS: Our findings suggest that chronic opioid dependence may cause reduced function of the HPA axis, while opioid withdrawal may decrease the response of the pituitary to CRH and increase the adrenal response to ACTH.

Socio-demographic and clinical characteristics of 3129 heroin users in the first methadone maintenance treatment clinic in China.

BACKGROUND: This study aimed to determine the characteristics of heroin users in the first methadone maintenance treatment (MMT) clinic in China. METHODS: In a retrospective chart review, the notes of 3127 heroin users who received both detoxification and MMT at the clinic were analyzed. Their socio-demographic and clinical data were collected, and the frequency of human immunodeficiency virus (HIV), Hepatitis C virus (HCV), and syphilis infections was investigated. RESULTS: The main findings are as follows: (1) 66.5% of the patients were younger than 35 years; (2) 55.1% were married at admission; (3) 32% were non-local residents; (4) the majority had high school level education, a history of smoking and alcohol consumption prior to the initial heroin use, and did not have stable jobs; (5) 28.4% were self-employed; (6) 5.4% of the sample had total hearing loss coupled with loss of speech; (7) 83.4% sniffed heroin or injected it intravenously at the time of admission, but 87.2% had smoked the drug when they first began abusing it; (8) a significant proportion of the patients were infected with HIV, HCV, and syphilis. CONCLUSIONS: Some of the above findings are not consistent with the results of previous studies conducted in Western countries and China. The unique socio-cultural and clinical characteristics of heroin abusers in different regions of China should be considered when MMT services are planned.