Opiates cognitive effects

The promising findings of the trials already mentioned, as well as the possible benefits of opiate antagonists in treating symptoms of schizophrenia or bipolar disorder without alcohol dependence or co-morbid alcohol and cocaine dependence, however, warrant studies in these difficult-to-treat populations ( 419, 420, 421 and 422). Furthermore, some data support a synergistic therapeutic effect when naltrexone is combined with cognitive-behavioral therapy ( 423). 

Curran, H. V. et al., Effects of methadone on cognition, mood and craving in detoxifying opiate addicts a dose-response study, Psychopharmacology, 154, 153, 2001. 

In nine prospective, longitudinal, multicenter studies, 1227 infants who were exposed in utero to cocaine (n = 474), opiates (n = 50), cocaine + opiates (n = 48), or neither (n = 655) were followed for 1-3 years after birth. Prenatal exposure to cocaine and/or opiates was not associated with mental, motor, or behavioral defects after controlling for birth weight and environmental risks. This result should be treated with caution, since the effects of prenatal opiates or cocaine exposure may become more evident as more advanced motor, cognitive, language, and behavioral skills develop (57). 

Prior use of benzodiazepines or opiates limits the psychotomimetic effects of ketamine. There has been a double-blind, placebo-controlled study of the role of lorazepam in reducing these effects after subanesthetic doses of ketamine in 23 volunteers who received lorazepam 2 mg or placebo, 2 hours before either a bolus dose of ketamine 0.26 mg/kg followed by an infusion of 0.65 mg/kg/hour or a placebo infusion (438). The ability of lorazepam to block the undesirable effects of ketamine was limited to just some effects. It reduced the ketamine-associated emotional distress and perceptual alterations, but exacerbated the sedative, attention-impairing, and amnesic effects of ketamine. However, it failed to reduce many of the cognitive and behavioral effects of ketamine. There were no pharmacokinetic interactions between subanesthetic doses of ketamine and lorazepam. 

Is dendritic arborization and synapse number important for variability in cognitive ability (Anderson Donaldson 1995) Zagon has reported that postnatal administration of naltrexone, an opiate receptor antagonist, augments rat brain size and increases cortical neuron dendritic arborization (Hauser et al 1989, Zagon McLaughlin 1984). In MAM-treated rats, I showed that postnatal treatment with naltrexone could ameliorate the behavioural deficit for attention to novelty, habituation performance and response flexibility (see Fig. 5) with intermediate effects on time to perform a reasoning task. 

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