Suicide

Suicide was the act of killing of one's self. Many robots, such as K9 and the Pain-Maker, were built with a self-destruct function. This usually resulted in an explosion. (K9TV: Regeneration, Robot Gladiators, Hound of the Korven) Cyborgs such as Daleks could also self-destruct. (DW: Remembrance of the Daleks, Dalek, DWBIT: Extermination of the Daleks)

In 1580, the Saturnyn calling herself Rosanna Calvierri committed suicide after the Eleventh Doctor defeated her plan to save her people. (DW: The Vampires of Venice)

In 1890, Vincent van Gogh committed suicide. (DW: Vincent and the Doctor)

In 1898, Gordon Seavers committed suicide after Richard Harries blackmailed him. (EDA: The Banquo Legacy)

In 1930 in an alternate timeline, Edith Thompson committed suicide because Charley Pollard died in the crash of the R101. This created a paradox, as Charley hadn't died, but had been saved by the Eighth Doctor. The paradox was resolved when the Doctor talked Edith out of suicide. (BFA: The Chimes of Midnight)

In 1945, Adolf Hitler committed suicide at the end of World War II rather than face capture or defeat. (PDA: The Shadow in the Glass)

In 1963, at the end of the Shoreditch Incident, the Supreme Dalek self-destructed when the Seventh Doctor revealed that Skaro was destroyed. (DW: Remembrance of the Daleks)

In 1977, Maximillian Stael committed suicide rather than be transformed into Fendahleen. (DW: Image of the Fendahl)

In 1999, Alex Hopkins committed suicide after killing the rest of the Torchwood Three team, having used the psychic locket to see a vision of the 21st century. (TW: Fragments)

In 2007, Suzie Costello committed suicide after her crimes were exposed. (TW: Everything Changes)

Later that year, John Ellis committed suicide after being displaced from 1953 and learning that his family was gone. (TW: Out of Time)

In an alternative reality, Donna Noble committed suicide by walking out in front of a lorry to prevent that world from ever being created in the first place. (DW: Turn Left)

In 2009, Owen Harper attempted suicide by drowning after the resurrection gauntlet was used to bring him back, reducing him to a zombie-like state. He later talked Maggie Hopley out of her attempt to suicide. (TW: A Day in the Death)

In the wake of the Dalek invasion of Earth later that year, suicide rates rose, the evidence for the existence of aliens leading to crises of faith. (TW: Children of Earth: Day One)

John Frobisher committed suicide after killing his wife and children to spare themselves from the 456. (TW: Children of Earth: Day Five)

After Miracle Day, in which people on Earth ceased to die, suicide became impossible, but some people became 'inventive', finding ways to get as close to death as possible. For example, the 45 Club believed that jumping from 45 floors up or higher was the only guaranteed way to lose consciousness forever. (TW: The Middle Men)

In 2012, a Dalek, which, after the Last Great Time War, the Ninth Doctor believed to be the last of its kind at the time, self-destructed when it was mutated by human DNA from Rose Tyler. (DW: Dalek)

In 2059, Adelaide Brooke committed suicide to restore the timeline after the Tenth Doctor altered it to save the crew of Bowie Base One. (DW: The Waters of Mars)

In the 22nd century, a group of Daleks on Earth initiated self-destruction after the Tenth Doctor used a proton cannon to make them intangible. (DWBIT: Extermination of the Daleks)

In the far future, Kane committed suicide after the Seventh Doctor revealed that his home planet Proamon had been destroyed in a supernova, leaving no one on whom he could take his revenge. (DW: Dragonfire)

In the far future, Cordo attempted suicide because he could not afford to pay the Company's taxes, but was stopped by the Fourth Doctor and Leela. (DW: The Sun Makers)

At the end of the Universe, the inhabitants of the Institute of Time committed suicide. (ST: The End)

In one possible timeline, Time Lords who committed suicide regenerated into a body of the opposite sex, this happened to the Doctor. (DWU: Exile)