The role of beta-adrenolytic drugs in treating anxiety disorders

Anxiolytic Effect of Carvedilol in Chronic Unpredictable Stress Model

Anxiety disorders are the most prevalent psychiatric disorders being also a comorbid state of other diseases. We aimed to evaluate the anxiolytic-like effects of carvedilol (CVD), a drug used to treat high blood pressure and heart failure with potent antioxidant effects, in animals exposed to chronic unpredictable stress (CUS). To do this, female Swiss mice were exposed to different stressors for 21 days. Between days 15 and 21, the animals received oral CVD (5 or 10 mg/kg) or the antidepressant desvenlafaxine (DVS 10 mg/kg). On the 22^nd day, behavioral tests were conducted to evaluate locomotor activity (open field) and anxiety-like alterations (elevated plus-maze—EPM and hole board—HB tests). After behavioral determinations, the animals were euthanized, and the adrenal gland, blood and brain areas, prefrontal cortex (PFC), and hippocampus were removed for biochemical analysis. CUS reduced the crossings while increased rearing and grooming, an effect reversed by both doses of CVD and DVS. CUS decreased the number of entries and permanence time in the open arms of the EPM, while all treatments reversed this effect. CUS reduced the number of head dips in the HB, an effect reversed by CVD. The CUS reduced weight gain, while only CVD5 reversed this effect. A reduction in the cortical layer size of the adrenal gland was observed in stressed animals, which CVD reversed. Increased myeloperoxidase activity (MPO) and interferon-γ (IFN-γ), as well as reduction of interleukin-4 (IL-4) induced by CUS, were reversed by CVD. DVS and CVD increased IL-6 in both brain areas. In the hippocampus, DVS caused an increase in IFN-γ. Our data show that CVD presents an anxiolytic effect partially associated with immune-inflammatory mechanism regulation.

The rise in prescribing for anxiety in UK primary care between 2003 and 2018: a population-based cohort study using CPRD

Background

Little is known about trends in prescribing of anxiolytics (antidepressants, benzodiazepines, beta-blockers, anticonvulsants, and antipsychotics) for treatment of anxiety. Several changes may have affected prescribing in recent years, including changes in clinical guidance.

Aim

To examine trends in prescribing for anxiety in UK primary care between 2003 and 2018.

Design and setting

A population-based cohort study using Clinical Practice Research Datalink (CPRD) data.

Method

Analysis of data from adults (n = 2 569 153) registered at CPRD practices between 2003 and 2018. Prevalence and incidence rates were calculated for prescriptions of any anxiolytic and also for each drug class. Treatment duration was also examined.

Results

Between 2003 and 2018, prevalence of any anxiolytic prescription increased from 24.9/1000 person-years-at-risk (PYAR) to 43.6/1000 PYAR, driven by increases in those starting treatment, rather than more long-term use. Between 2003 and 2006, incidence of any anxiolytic prescription decreased from 12.8/1000 PYAR to 10.0/1000 PYAR; after which incidence rose to 13.1/1000 PYAR in 2018. Similar trends were seen for antidepressant prescriptions. Incident beta-blocker prescribing increased over the 16 years, whereas incident benzodiazepine prescriptions decreased. Long-term prescribing of benzodiazepines declined, yet 44% of prescriptions in 2017 were longer than the recommended 4 weeks. Incident prescriptions in each drug class have risen substantially in young adults in recent years.

Conclusion

Recent increases in incident prescribing, especially in young adults, may reflect better detection of anxiety, increasing acceptability of medication, or an earlier unmet need. However, some prescribing is not based on robust evidence of effectiveness, may contradict guidelines, and there is limited evidence on the overall impact associated with taking antidepressants long term. As such, there may be unintended harm.

The Computational, Pharmacological, and Physiological Determinants of Sensory Learning under Uncertainty

The ability to represent and respond to uncertainty is fundamental to human cognition and decision-making. Noradrenaline (NA) is hypothesized to play a key role in coordinating the sensory, learning, and physiological states necessary to adapt to a changing world, but direct evidence for this is lacking in humans. Here, we tested the effects of attenuating noradrenergic neurotransmission on learning under uncertainty. We probed the effects of the β-adrenergic receptor antagonist propranolol (40 mg) using a between-subjects, double-blind, placebo-controlled design. Participants performed a probabilistic associative learning task, and we employed a hierarchical learning model to formally quantify prediction errors about cue-outcome contingencies and changes in these associations over time (volatility). Both unexpectedness and noise slowed down reaction times, but propranolol augmented the interaction between these main effects such that behavior was influenced more by prior expectations when uncertainty was high. Computationally, this was driven by a reduction in learning rates, with people slower to update their beliefs in the face of new information. Attenuating the global effects of NA also eliminated the phasic effects of prediction error and volatility on pupil size, consistent with slower belief updating. Finally, estimates of environmental volatility were predicted by baseline cardiac measures in all participants. Our results demonstrate that NA underpins behavioral and computational responses to uncertainty. These findings have important implications for understanding the impact of uncertainty on human biology and cognition.