The disappearance in 1995 of the Welsh rock musician Richey Edwards, then aged 27, became a major British media event and, in the years that followed, supposed sightings of (or messages from) Edwards, akin to those of Elvis Presley in the US, lent a bizarre aspect to his supposed death. Edwards, whose parents have been granted a court order declaring him to be presumed dead, was himself a student of rock music history and popular culture, and would surely have been amused to find himself the object of so much speculation and intrigue.

Amused but not surprised: as a member of the Welsh rock group the Manic Street Preachers, Edwards had often courted controversy and commanded a loyal following. Edwards' talent was not that of a musician - he could barely play the guitar - but as a lightning rod of sorts for adolescent angst. A handsome, gaunt man, Edwards embodied similar qualities to the 18th-century poet Thomas Chatterton or, more recently, the rock singer Pete Doherty. The irony of his disappearance is that it led to the Manic Street Preachers becoming one of Europe's most popular bands in the mid-1990s, his absence allowing the three remaining musicians to create more mainstream rock-pop.

Richard James Edwards grew up in Blackwood, south Wales, where he attended Oakdale comprehensive. Between 1986 and 1989, he attended the University of Wales, Swansea, graduating with a degree in political history. While there he befriended Nicky Wire. Wire was playing guitar in a punk band, initially called Betty Blue before changing to the Manic Street Preachers, and Edwards became the band's roadie and driver. When the band's bassist quit, Wire shifted to bass and Edwards, who had begun collaborating with Wire on song lyrics and design, joined as rhythm guitarist. That he possessed no musical ability was not a problem - pale and thin, Edwards looked like a rock music archetype. While in the band he preferred to be referred to as Richey James.

In August 1989 the band independently issued their debut single Suicide Alley. The following year they issued the EP New Art Riot on the Damaged Goods label. This attracted interest from the UK music press due to their attacks on fellow rock musicians. A management deal followed and the band released the January 1991 single Motown Junk via Heavenly Records. This attracted press attention with such combative lyrics as, "I laughed when Lennon got shot."

The Manic Street Preachers' confrontational attitude looked back to British punk rock, and their concerts also aped the chaos of that era. This proved a perfect mix for the music press, which began championing the band. When the NME journalist Steve Lamacq questioned the band's commitment, Edwards grabbed a razor-blade and carved "4 REAL" into his own forearm. The wound received 17 stitches and the glossy photographs taken of the gory graffiti helped confirm to teenagers that here was a band who "meant it". In the wake of the ensuing publicity Sony Records signed the band and, in 1992, they issued Generation Terrorists, an ambitious double-album on which each of the 18 songs was accompanied by a literary quotation. While reviews were mixed - the band's limited musical ability and reliance on aggressive posturing alienated many - Generation Terrorists sold over 250,000 copies and established the Manic Street Preachers as Britain's new indie rock hope.

In September 1992 the band's recording of Theme from MASH (Suicide is Painless) reached No 7 in the UK singles chart and suggested they might have wide appeal. Edwards, by now the focus of intense fan devotion, enjoyed fame but began showing signs of emotional instability. Self-mutilation (often burning himself with cigarettes), anorexia nervosa (for which he wrote the song 4st 7lb) and alcoholism combined to make him increasingly unreliable. In 1994 he was admitted to the Priory hospital for treatment. The band played on as a three-piece - Edwards' guitar amplifier had often been turned down low, so his absence did not affect their sound.

While the band's 1993 album Gold Against the Soul had not been strongly received, their third album, The Holy Bible (1994) - with a Jenny Saville painting on the cover - re-established their critical worth. Most of The Holy Bible's lyrics were written by Edwards and, under the influence of Sylvia Plath, expressed the depths of depression.

Edwards was booked to travel to the US on February 1 1995 with the band's singer James Dean Bradfield for promotional duties, but never took the flight. Little is known about his movements in the following days, although it appears he left London for Wales. On February 14 that year his abandoned Vauxhall Cavalier received a parking ticket at the Severn service station, and it is widely believed that he jumped to his death from the Severn Bridge.

Edwards is survived by his parents, Graham and Sherry, and sister Rachel.

• Richard (Richey) James Edwards, rock musician, born December 22 1967; declared dead November 23 2008