Repurposing a blood pressure drug for anxiety reveals unexpected sex differences in attention

A recent study published in the Journal of Affective Disorders indicates that a widely used blood pressure medication, losartan, may help alleviate anxiety while simultaneously altering the way individuals process attention to emotional stimuli. Researchers have discovered that losartan affects how the brain processes distractions; however, this impact seems to vary between males and females.

The findings highlight the potential of medications targeting the body's blood pressure systems as novel treatments for anxiety disorders. Attentional control, a crucial mental ability in daily life, involves two components: goal-directed regulation, which entails intentionally focusing on a specific task, and stimulus-driven capture, wherein a sudden or emotionally charged event automatically draws one's focus.

An imbalance between these two attention processes is commonly observed in individuals with anxiety, making them more prone to distraction by potential threats and struggling to disengage from stressors intentionally. Previous research indicates that the renin-angiotensin system, a network traditionally associated with blood pressure regulation, also significantly influences brain regions responsible for emotion and cognitive regulation.

The primary chemical messenger in this system exerts its effects on specific receptors in the brain. Animal studies and early human trials suggest that temporarily inhibiting these receptors using losartan—a common blood pressure medication—could potentially reduce anxiety and enhance a person's ability to regulate fear. Professor Benjamin Becker of the SRT AI, Society and Social Dynamics and the Department of Psychology at The University of Hong Kong notes that "Recent animal studies and neuroimaging studies in humans have shown that targeting the angiotensin-renin system can modulate brain circuits related to fear and motivation.

These receptors can be readily blocked by common blood pressure medications (such as losartan) which specifically block the angiotensin-II type 1 (AT1) receptor." The study's researchers hypothesized that blocking these receptors might enhance focus due to their presence in brain regions linked to inhibitory control. Moreover, the distribution and activity of these receptors differ between biological sexes, implying that treatments targeting these receptors could yield sex-specific effects.

To investigate these dynamics, the authors conducted a randomized, double-blind, placebo-controlled experiment involving 79 healthy university students, comprising 39 women and 40 men aged 18 to 29. Participants were randomly assigned to receive either a single 50-milligram dose of losartan or a placebo pill. Neither the participants nor the researchers knew who received which pill until the study's conclusion.

Anxiety levels were assessed using standard questionnaires before and after the drug administration. Attentional control was measured through an eye-tracking task called the anti-saccade task. During the 40-minute computer-based task, participants examined a screen displaying either emotional faces or simple non-social shapes, with two conditions: pro-saccade (looking towards the image for rapid, reflexive attention) and anti-saccade (focusing on the opposite side of the screen to suppress the natural reflex).

Specialized cameras recorded the exact location and speed of eye movements in pixels and milliseconds. Performance was analyzed for spatial accuracy and reaction time, with statistical controls for baseline anxiety levels. The results revealed that the single losartan dose reduced overall state anxiety across the entire group, irrespective of sex.

However, the effects on cognitive/attentional control differed significantly between males and females.