An unexpected cause of low cortisol in the morning has been identified

People with pronounced primary psychopathic traits have lower morning levels of cortisol—a key stress hormone—than others. This conclusion was reached by researchers in the USA after studying hormonal indicators in university students.

As reported by BAKU.WS with reference to the journal Social Neuroscience, the study examined the relationship between psychopathic personality traits and levels of cortisol and testosterone. Psychopathic traits include emotional coldness, empathy deficit, lack of guilt, and a tendency toward manipulation. In psychology, these traits are typically divided into primary and secondary psychopathy: the first is associated with low anxiety and weak response to threats, while the second is characterized by impulsivity, emotional instability, and increased sensitivity to stress.

The authors of the work led by Todd Armstrong analyzed data from 552 undergraduate students with an average age of about 20 years. Participants completed psychological questionnaires, after which saliva samples were taken to determine hormone levels.

The sampling was conducted at different times of the day—from morning to evening—which allowed researchers to assess daily hormonal fluctuations. In addition, students performed a brief stressful task: a two-minute speech about their strengths and weaknesses, after which the hormonal analysis was repeated.

The results showed that lower baseline cortisol levels before the stressful task are characteristic of people with pronounced primary psychopathic traits, but this relationship was observed only in the morning hours. In the second half of the day, the correlation disappeared and did not differ between men and women. No relationship was found between cortisol levels and secondary psychopathy.

According to the researchers, the obtained data indicate the important role of cortisol in the biological mechanisms underlying primary psychopathic traits. "Although attention in recent years has been paid to the interaction between testosterone and cortisol, our results show that the direct relationship between cortisol and psychopathic traits may be of key importance," the authors of the study noted.