If the findings of a recent study are accurate, the next time you order strong coffee, you might be asked if you want cream, sugar, or anti-psychotic medications to go with it. According to researchers from the University of Innsbruck, those whose tastes favor black coffee and other bitter flavors, such as dark chocolate and tonic water are more likely to suffer from sadistic or psychopathic personality disorders.

The study, published in the January 2016 issue of Appetite, studied the self-reported taste preferences of test subjects and compared them to the results of personality questionnaires assessing Machiavellianism, psychopathy, narcissism, everyday sadism, trait aggression, and the Big Five factors of personality. The results “confirmed the hypothesis that bitter taste preferences are positively associated with malevolent personality traits, with the most robust relation to everyday sadism and psychopathy.”

The researchers also found that people who enjoyed milky or sugary coffee or other sweet flavors generally tend to have more “agreeable” personality traits like sympathy, cooperation, and kindness. The closest correlation found in the study was between bitter foods, like radishes and tonic water, and “everyday sadism,” or the enjoyment of inflicting moderate levels of pain on others.

Perhaps more alarming was the additional finding that the correlation between bitter foods and psychopathic tendencies could “become chronic” and get worse with time. Of course, coffee drinkers are rarely associated with being the most cordial of people, anyway — particularly before the first cup of the day. Even so, it might be best to keep one eye on the person at the next table — or within your house — who declines the offer of cream and sugar.

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Read more fun facts about psychology.