Paranoia

Paranoia was defined by the Seventh Doctor as "a heightened appreciation of how badly the universe wants to get you". (PROSE: Original Sin)

Some substances were capable of causing paranoia. These included drugs such as skar, (PROSE: Catastrophea) skoob (PROSE: Mean Streets) and Sarg (PROSE: Deadly Reunion) or exposure to materials such as icarons. (PROSE: Original Sin) Paranoia was a symptom of robophobia. (TV: The Robots of Death)

Harry Randall suffered from paranoia. (AUDIO: The Magic Mousetrap)

Paranoia thrived on the Internet in the early 21st century, which helped give rise to the Church of the Grey. (PROSE: Where Angels Fear)

In 2006, the crash of an alien spaceship in London and the British government not responding led to paranoia sweeping the United Kingdom, with at least three reports of people being falsely identified as aliens and assaulted. (TV: Aliens of London)

Miss Kizlet's tablet was capable of changing one's level of paranoia. (TV: The Bells of Saint John)

In 2069, the Shift introduced the concept of paranoia to Marie, who turned her weapons systems against herself. (PROSE: Alien Bodies)

On Frontios, Range accused Plantagenet of paranoia when he suspected the Fifth Doctor being responsible for the meteorites bombarding the colony. (TV: Frontios)