He was paralyzed from the chest down in March 2007 when a rugby scrum collapsed on top of him during match practice, dislocating his spine, the UK's Press Association has reported.
James of Worcester had played rugby for England under-16s and was a university student at the time of his injury last year. He is believed to be the youngest person from the UK to have traveled to Switzerland to commit suicide.
Worcestershire Coroner's Service, which is conducing an inquest into the circumstances of his death, states on its Web site that James died on September 12 after he "traveled to Switzerland with a view to ending his own life. He was admitted to a clinic where he died."
The inquest was adjourned on September 19 for reports. Assisted suicide is illegal in the UK.
In a statement Friday, reported by PA, James' parents said that he had attempted to kill himself several times already.
"His death was an extremely sad loss for his family, friends and all those that care for him but no doubt a welcome relief from the 'prison' he felt his body had become and the day-to-day fear and loathing of his living existence, as a result of which he took his own life.
"This is the last way that the family wanted Dan's life to end but he was, as those who know him are aware, an intelligent, strong-willed and some say determined young man," PA reported James' parents as saying.
"The family suffered considerably over the last few months and do wish to be left in peace to allow them to grieve appropriately."
James' parents added that their son, "an intelligent young man of sound mind," had never come to terms with his condition and was "not prepared to live what he felt was a second-class existence".
Adrian Harling, the family solicitor, would not comment on the investigation, PA reported.
The clinic Dignitas, where all known British assisted suicides have taken place, said that due to privacy laws it could not disclose whether James was one of its members.
Det Insp Adrian Todd, of West Mercia Police, said: "A police investigation is ongoing and officers have spoken with a man and a woman in connection with the case.
"A report will later be submitted to the Crown Prosecution Service and an inquest into the death will take place in due course."
BBC correspondent Imogen Foulkes, in Berne, said assisted suicide has raised issues of concern in Switzerland.
She said it was permitted as long as the person carries out the act themselves and the helper has no "direct interest".
Dignitas offers help to people to end their lives if they are suffering a terminal illness, a chronic condition (including paralysis) or a mental illness.
The only stipulation is that a patient has expressed a wish to die and this has been certified by a doctor.
But the actions of Dignitas have provoked controversy and disquiet in Switzerland.
The issue of assisted suicide is now the subject of a government inquiry, the results of which are expected to be released early next year.
The inquiry will look at the counsel and care provided by assisted suicide groups and the practice of offering assisted suicide to non-Swiss citizens.