The language of serial killers: communicative patterns in interviews with psychopaths diagnosed with antisocial personality disorder

Psychopaths diagnosed with Antisocial Personality Disorder (ASPD) often display behaviors that largely diverge from societal norms, such as callousness, manipulativeness, impulsivity, risk-taking, and attention-seeking. This study explored whether people with these disorders also exhibit specific forms of language use. More specifically, it addresses two main questions: 1) What are the most common linguistic traits found in the speech of people diagnosed with Psychopathy and ASPD? and 2) What distinctive linguistic traits, if any, are peculiar to the speech of specific psychopathic individuals? To explore these questions, I adopted a corpus-driven approach, analyzing the transcripts of interviews with four infamous serial killers —John Gacy, Ted Bundy, David Berkowitz, and Jeffrey Dahmer— who all meet the criteria for psychopathy and ASPD. The corpus was examined by using AntConc so as to identify recurring linguistic patterns, including frequent words, clusters, N-Grams, and keywords, and the UCREL Semantic Analysis System (USAS) to identify the thematic focus of the texts. The findings revealed both shared and unshared properties of the interview data analyzed. In line with the literature on the language of psychopathic and antisocial individuals, the findings highlight common traits such as self-referential language, a focus on crime and violence, and a high incidence of negation. Additionally, they also show linguistic features not previously identified in the literature such as the use of "you" for self-reference, frequent combinations of "I" with experiential verbs in negative constructions, a preference for third-person pronouns with experiential, stative, and action verbs in the affirmative form. Finally, they revealed preferential semantic categories identified through automatic semantic tagging. These categories include grammar, temporal and spatial circumstances, people and relationships, and religion. Furthermore, the study revealed that each sub-corpus is focused on recurrent themes, which are not as prominently instantiated in the corpus as a whole. These themes include, for example, Gacy’s emphasis on physical spaces, sexuality and work environment; Bundy’s focus on identity, legal and geographical features; Berkowitz’s insistence on religion, family and occult beliefs; and Dahmer’s attention to crime, substance use and anatomical references.