Ten male opiate addicts, who were current heroin injectors, underwent positron emission tomographic (PET) scanning during exposure to a sequence of six alternating drug related and neutral video cues, on two occasions. After the second scan, each subject received heroin or placebo using a randomised single-blind procedure. This design allowed the investigation of patterns of brain activity during a range of self-reported cue evoked emotional states, both in the presence and absence of heroin. Self-reports of 'urge to use' correlated strongly with increased regional blood flow (rCBF) in the inferior frontal and orbitofrontal cortex target regions of the mesolimbic dopaminergic system, implicated in conditioning and reward. 'Urge to use' was also associated with highly significant increased rCBF in the right pre-cuneus, an area associated with episodic memory retrieval, and in the left insula, implicated in the processing of the emotional components of stimuli. Self-reports of feeling 'high' correlated with rCBF activation in the hippocampus, an area relevant to the acquisition of stimulus-associated reinforcement.
The neurobiological mechanisms of opiate addictive behaviour in humans are unknown. A proposed model of addiction implicates ascending brainstem neuromodulatory systems, particularly dopamine. Using functional neuroimaging, we assessed the neural response to heroin and heroin-related cues in established opiate addicts. We show that the effect of both heroin and heroin-related visual cues are maximally expressed in the sites of origin of ascending midbrain neuromodulatory systems. These context-specific midbrain activations predict responses to salient visual cues in cortical and subcortical regions implicated in reward-related behaviour. These findings implicate common neurobiological processes underlying drug and drug-cue-related effects.
Subjects articulated a consistent desire for IOT in order to 'stabilize' their lives in a number of ways. This sample was recruited from one of the country's largest specialist IOT clinics. The generalizability of this study's findings to all patients in the United Kingdom currently prescribed IOT, however, was not examined. Nevertheless, these findings suggest that clinicians and policy makers should be aware of many heroin users' perception of IOT as long-term treatment and their clear preference for injectable diamorphine. Further investigation of differential outcomes between oral and injectable OT and between different injectable opiates is warranted.
The vast majority of substitute prescribing to opiate addicts in England and Wales is of oral methadone. The prescription of diamorphine, dipipanone and cocaine to addicts is allowed subject to the 1971 Misuse of Drugs Act. Prescription of these drugs has aroused international interest and controversy in the United Kingdom although research is scanty. This report is a description of the current attitudes about, and practice of, prescribing diamorphine, dipipanone and cocaine by medical practitioners in the addiction field in England and Wales. A questionnaire was devised and sent to drug services in England and Wales which provided a prescribing service. Among respondents who reported that they currently hold a licence for heroin, dipipanone or cocaine, the number of patients treated by each doctor varied widely; from a handful of patients to 100 heroin patients. Dosage currently used ranged from a minimum of 10 mg to a maximum of 1000 mg daily for heroin. Doses of dipipanone were lower. More respondents thought that heroin and dipipanone were clinically justified in some situations than thought that they should never be prescribed, while the opinions were reversed in the case of cocaine.
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