Pharmacological manipulations of arousal and memory for emotional material: effects of a single dose of methylphenidate or lorazepam

Abstract

Benzodiazepines produce robust impairments of memory alongside global decreases in physiological and subjective arousal. Recently one benzodiazepine (triazolam) has been found to disproportionately impair memory for emotionally arousing material (Buchanan et al., 2003). The extent to which this effect may be mediated by the drug's sedative action is unclear. The present study aimed to assess how pharmacologically decreasing physiological arousal with a benzodiazepine and increasing arousal with a stimulant impact on memory for emotional material. A double-blind placebo controlled trial with 48 volunteers was used to investigate the effects of methylphenidate (40 mg) and Lorazepam (1.5 mg) on incidental memory for emotional material in Cahill and McGaugh's (1995) slide-story task. The slide-story was presented to participants administered either active drug or placebo and retrieval was assessed one week later. Methylphenidate produced stimulant effects and Lorazepam produced sedative effects. Significantly enhanced memory for emotional material was observed in participants given placebo, but not in those given either methylphenidate or Lorazepam. Despite producing opposite effects upon arousal, both methylphenidate and Lorazepam lessen the impact of emotionally arousing material on memory. The effects of Lorazepam add to a growing literature that benzodiazepines may exert their clinical, anxiolytic effects in part via altering emotionaL cognitive function.

Human genome–guided identification of memory-modulating drugs

“…Despite producing opposite effects on sleepiness, both lorazepam and methylphenidate reduce the impact of emotionally arousing aversive material on memory, indicating a dissociation between drug effects on aversive memory and drug effects on sleepiness (32). Furthermore, a study with the sedative lorazepam found drug-induced memory impairments independent of emotional valence (33).…”

Acute and long-term effects of adolescent methylphenidate on decision-making and dopamine receptor mRNA expression in the orbitofrontal cortex

“…While there is evidence that MPH can improve declarative memory [43] and cognitive control [44] in college students, it is important to note that nonmedical users tend to have lower grade point averages [45], calling into question the long term success of such use. Regardless, the results presented here seem to be consistent with findings that MPH exposure can improve learning performance under specific circumstances even when administered in late adolescence.…”

The Role of the Amygdala in Anxiety Disorders

“…These studies have found that benzodiazepines have the ability to impair functions related to amygdala activity including fear conditioning [184][185][186], recognition of fearful emotional faces [187], and memory for emotional stimuli relative to neutral stimuli [188,189].…”

“…As discussed in the human studies in Section 4.1 above [184,188,189], a key aspect of benzodiazepine action may be the ability to modulate emotional memory. Here the BLA once again appears to be a main site of benzodiazepine action.…”