Personal and social factors
Various personal and social factors may influence the personal choice of whether to join a terrorist group or attempt an act of terror, including:

Identity, including affiliation with a particular culture, ethnicity, or religion
Previous exposure to violence
Financial reward (for example, the Palestinian Authority Martyrs Fund)
Mental health disorder
Social isolation
Perception that the cause responds to a profound injustice or indignityA report conducted by Paul Gill, John Horgan and Paige Deckert found that for "lone wolf" terrorists:
43% were motivated by religious beliefs
32% had pre-existing mental health disorders, while many more are found to have mental health problems upon arrest
At least 37% lived alone at the time of their event planning and/or execution, a further 26% lived with others, and no data were available for the remaining cases
40% were unemployed at the time of their arrest or terrorist event
19% subjectively experienced being disrespected by others
14% percent experienced being the victim of verbal or physical assaultAriel Merari, a psychologist who has studied the psychological profiles of suicide terrorists since 1983 through media reports that contained biographical details, interviews with the suicides families, and interviews with jailed would-be suicide attackers, concluded that they were unlikely to be psychologically abnormal. In comparison to economic theories of criminal behaviour, Scott Atran found that suicide terrorists exhibit none of the socially dysfunctional attributes—such as fatherless, friendless, jobless situations—or suicidal symptoms. By which he means, they do not kill themselves simply out of hopelessness or a sense of having nothing to lose.Abrahm suggests that terrorist organizations do not select terrorism for its political effectiveness.
During the Reign of Terror, which began in July 1793 and lasted thirteen months, Paris was governed by the Committee of Public Safety who oversaw a regime of mass executions and public purges.Prior to the French Revolution, ancient philosophers wrote about tyrannicide, as tyranny was seen as the greatest political threat to Greco-Roman civilization. Medieval philosophers were similarly occupied with the concept of tyranny, though the analysis of some theologians like Thomas Aquinas drew a distinction between usurpers, who could be killed by anyone, and legitimate rulers who abused their power—the latter, in Aquinas view, could only be punished by a public authority. John of Salisbury was the first medieval Christian scholar to defend tyrannicide. Most scholars today trace the origins of the modern tactic of terrorism to the Jewish Sicarii Zealots who attacked Romans and Jews in 1st-century Palestine. They follow its development from the Persian Order of Assassins through to 19th-century anarchists. The "Reign of Terror" is usually regarded as an issue of etymology. The term terrorism has generally been used to describe violence by non-state actors rather than government violence since the 19th-century Anarchist Movement.In December 1795, Edmund Burke used the word "Terrorists" in a description of the new French government called Directory:
At length, after a terrible struggle, the [Directory] Troops prevailed over the Citizens ... To secure them further, they have a strong corps of irregulars, ready armed.