Opioid Use Disorder __________________________________________________________________________
In addition, chronic opioid use may contribute to low bone mineral density through reduction in lumbar bone mineral density. Growth hormone axis abnormalities are also seen in heroin addicts [91]. NEUROCOGNITIVE EFFECTS Cognitive impairment resulting from chronic drug use may contribute to abuse and dependence in at least two ways. The first involves increasing the likelihood of drug-seeking behavior through various induced cognitive deficits, such as failure of impulse control mechanisms. The second involves the interference with users’ ability to assimilate and participate in rehabilitation programs that have an educative and cognitive emphasis [94; 95]. The chronic use of illicit drugs is often associated with a generalized profile of neuropsychologic deficit. However, it is thought that important differences in the patterns of interac- tion associated with various neurotransmitter systems, coupled with corresponding differences in the distributions of receptor subtypes, are responsible for the distinct neurocognitive effects of specific drugs of abuse [94]. Compared with marijuana and stimulants, there has been substantially less research into neuropsychologic deficits in chronic opioid abusers. Early studies found relatively little impairment in tasks involving abstraction and reasoning, leading investigators to conclude that chronic opioid use was not associated with deficient frontal lobe functioning. How- ever, newer studies, utilizing more sensitive measures, have demonstrated that opioid abusers do possess marked deficits in frontal lobe functioning relative to healthy control subjects. These deficits may include problems with altered attentional control, altered decision making, or problems with choices involving motivationally significant outcomes [94]. Additional research is needed to establish whether this pattern reflects increased impulsivity. It should be noted that determining causation in studies involving drug users is difficult due to comorbid psychiatric disorders and polysubstance abuse [94]. Cognitive-Motor Effects of Methadone Maintenance While under the influence of acute opioid ingestion, the ability to work safely or drive a car can be impaired. This does not appear to be the case with methadone patients who have adapted to the effects of opioids for months or even years, a reflection of the substantial tolerance to the central depress- ing effect when opioids are taken regularly on a long-term basis [96]. A review of the cognitive functioning of methadone patients found that [96]: • On measures of concentration and attention, metha- done patients tended to perform less well than controls. • Methadone patients performed equally or slightly faster in speed of information processing and equally or slightly worse in motor reaction on measures of simple reactions and simple-choice reactions.
• Performance was inconsistent on complex-choice reac- tions under reactive stress. • No evidence for inferior performance of methadone patients in vigilance tasks has been found. • Methadone patients have performed worse than control groups in visual orientation. • In tests combining tracking with a reaction task, slower reaction to peripheral signals have been observed in methadone patients together with equal accuracy and greater tracking deviation or smaller number of correct responses and equal tracking deviation. Researchers concluded that among methadone-maintained patients without complicating comorbidity, visual structuring and reaction are not impaired [96]. Performance of attention, visual orientation, and eye-hand coordination are worsened. In general, performance of methadone patients and comparable healthy subjects overlap to a substantial degree. The study results may be better explained by sociodemographic factors than by the grouping factor; age, gender, and educational attainment showed a greater influence than methadone use. The authors concluded that being a methadone patient does not necessarily mean that impairment of cognitive-motor skills performance is inevitable [96]. Authors of more recent studies have reported similar findings [97; 98]. The practical application of these findings suggests that methadone-maintained patients may be as capable as healthy persons in job performance. If job demands encompass skills with no differences found between healthy subjects and methadone patients, if minimum prerequisites are not extraordinarily high, or if patients exhibit favorable features exclusive of their methadone dependence, job performance is unlikely to be affected [96]. OPIOID OVERDOSE As discussed, there were approximately 81,230 drug-overdose deaths in the United States in the 12-month period ending in May 2020 [17]. In 2021, 106,699 drug-overdose deaths occurred in the United States, representing a 14% increase from 2020 [37]. Between 1999 and 2021, the age-adjusted death rate from drug overdose rose significantly (from 6.1 per 100,000 in 1999 to 32.4 in 2021) [37]. Overdose death rates from synthetic opioids other than methadone (e.g., fentanyl/ fentanyl analogs, tramadol) increased from 0.3 per 100,000 in 1999 to 4.0 in 2021. The heroin overdose death rate increased from 0.7 per 100,000 in 1999 to 2.8 per 100,000 in 2021, a decrease from 4.1 in 2020 [37]. Overdose death rates involving natural and semisynthetic opioids (e.g., oxycodone, hydrocodone) increased from 1.2 per 100,000 in 2001 to 3.5 per 100,000 in 2010, then did not change significantly from 2010 through 2021, where the rate remained at 4.0 in 2020 and 2021 [37]. Overdose deaths involv- ing methadone increased from 0.5 per 100,000 in 2001 to 1.8
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MDRI2026
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