Sudesh Amman was the most recent "terrorist" to strike London. As he was under police surveillance he was quickly shot dead by police before he was able to inflict mass carnage, if that were his intention. He did however stab two random members of the public.
Amman had been released from prison just 10 days earlier having been sentenced for possessing and distributing terrorist documents, presumably papers supporting terrorist acts.
As is most often the case, no links have been established between Amman and any known terrorist organisations.
However, what has now been widely reported (1 week after the incident) as more information becomes available on Amman's life, is that he was a heavy user of marijuana.
It has long been established that their exists a link between marijuana and violence. Schizophrenia has also been linked to this drug, in that any person susceptible to this mental illness has a higher risk of falling victim to it if they use marijuana.
Schizophrenia is not a rare disorder and in fact 1 in 100 people globally are susceptible to it. In males the symptoms become apparent from 21 to 25 years. Females have two onsets, from 25 to 30, and from 40 to 50 years. As marijuana is a very common drug for teenagers, we need to be concerned about their future mental health.
People who smoke marijuana often experience a lower quality of life, depression, and relationship problems.
I suspect Amman was just another mentally ill loner who needed to feel a part of something bigger so wanted to be seen as a religious fanatic, and thus his demise mirrors that of so many before him.
This subject is explained in more detail in my book - Drugs: The Dark Side - where in Unit 3 I explain the dangers of Marijuana.