Terrorist behaviour is probably always determined by a combination of innate biological, early developmental, cognitive and temperament factors along with environmental influences, and group dynamics. The degree to which each of these factors contributes to attacks at the Brussels international airport and a city metro station probably varies between individual terrorists, between individual groups, and between types of groups. It is generally well accepted that terrorism involves aggression against non-combatants and terrorist action in itself is not expected by its perpetrator to accomplish a political goal but instead to influence a target audience and change that audience’s behaviour in a way that will serve the interests of the terrorist for a significant length of time. Individual membership in a terrorist organisation offers disciples a well-defined personal role, a righteous purpose, the opportunity for revenge for perceived humiliations, and the lifting of constraints on the expression of otherwise prohibited behaviours freeing the member from personal responsibility for attacks on out-groups. Whereas the group behaviour forces ideological indoctrination, repetitive training, and peer pressures, ultimately influencing the group’s violence, even when individual members are not predisposed to such behaviour. This occurs because collective identity subsumes individual identity. This fusion with the group seems to provide the necessary justification for their actions with an attendant loss of felt responsibility. The principal debate centres on whether group dynamics are sufficient in and of themselves to turn an average person into a terrorist or whether individual history and personality must be considered as well. The dynamics of living in a terrorist group tends to alienate one from others but the starting point and personal needs existing at the time of entry into a terrorist group are very different for different terrorists. This claim of initial psychological heterogeneity followed by group-induced homogenisation appears plausible, but it requires empirical verification. A clear connection is emerging between the men who carried out the Brussels airport and metro bombings and the Islamist cell behind the Paris attacks last November, in which 130 people died. Devastating attacks in Brussels are the latest phase of the war on Europe declared by the so-called Islamic State (IS). Capturing IS fighters to surrender is one of the crucial ways in which Western intelligence services would have to build up the picture of its European network. In order to establish their writ the ISIS suicide terrorist attacks seen in Brussels airport and metro red appear to have occurred as part of the organised political campaign, and were generally directed towards a strategic objective, which included innocent civilians because terrorists have learned that the tactic works. Although the tactic of suicide terrorism may present as the most innovative and a highly anxiety-provoking scenario, it is a combination of familiar methods, targets and motives. It can be interpreted as a particular case of oppositional terrorism rather than as a sui generis phenomenon. It shares with it many properties of general terrorism. In recent years, and particularly since Paris bombing attacks there has been a sharp threat in suicide terrorism in Europe, which has generated a hype in the media and academic literature that address a topic that is inherently fascinating: a modus operando that requires the death of its perpetrator masked behind the religious agenda to ensure its success. Arguably it raises a question whether a certain type of mind is disproportionately influenced with a given political category of terrorism, and teasingly invites a challenge to probe a psychological inquiry into the ‘mind of the terrorist’. It asks if those terrorist groups typically exhibit hierarchical organisation, with various roles assumed within that are unavailable for scholarly scrutiny or attempted replication. Attempts to account for the behaviour of terrorists fall into two general categories: top-down approaches that seek the seeds of terrorism in political, social, economic, or even evolutionary circumstances, and bottom-up approaches that explore the characteristics of individuals and groups that turn to terrorism. Outcasts who adhere to an anomalous scheme of values out of tune with that of the rest of society claim that there is a near similarity of fundamental characteristic in both the psychopath and the terrorist. It makes a common kind of sense that the relationship between insanity and terrorism might equally apply to the relationship between sociopathy and terrorism: sociopaths may sometimes be among terrorists, but terrorists are not, by virtue of their political violence, necessarily sociopaths. If neither insanity nor sociopathy nor rational choice can fully account for the genesis of terrorist behaviours, what alternative psychological explanations seem most plausible? In other words, although terrorists rarely exhibit psychological disorders, they may exhibit identifiable psychological traits or may have been influenced by identifiable social factors. Expressions of terrorism since the last decade of the 20th century are fundamentally new. It questions new aspects of terrorism, such as the transnational nature of perpetrators and their organisations, their religious inspiration and fanaticism, their use of weapons, and their indiscriminate targeting. It points out essential continuities with previous expressions of terrorist violence, such as national and territorial focus of new terrorists, their political motivations, their use of conventional weaponry, and the symbolic targeting that is still aimed at achieving a surprise effect. It would be silly to ignore that this calls for more thorough and collaborative investigations between counterterrorism departments and behavioral analysts in order to appreciate truly new aspects of terrorism. The writer is a professor of psychiatry and consultant forensic psychiatrist in the UK. He can be contacted at fawad_shifa@yahoo.com