Clone madness was an affliction of clones.
The reason for clone madness was a debated issue. Some scientists believed that it was because the body was grown too quickly, and the brain being fed information could not handle the amount of data at such a rate. Others believed that it was due to a "double presence" the clone caused in the Force.
The effects of clone madness afflicted many of the clones of Galen Marek whom Darth Vader had designed on Kamino in an effort to replace the original Starkiller with a more powerful and loyal version. Roughly six months after Marek's death, Vader almost came to believe one clone in particular might have been his first success. Although the clone did not possess any of the physical deformities or violent psychosis that the aberrant clones exhibited, he still suffered from an identity crisis to a certain extent. Ultimately, he suffered from the emotional imprints left behind by his genetic template, much like the clones who failed before him.
Before the Battle of Kamino, Darth Vader succeeded in creating the only perfect clone of the original Starkiller. Unlike the clones that preceded him, this clone was stable where the others weren't. Not only did he inherit Marek's powers, he could also hold his progenitor's memories as separate from his own experience. The clone eventually managed to free himself from his template's emotions by truly realizing that he was the clone of a dead man, thus avoiding the identity crisis and other psychological impediments that undermined all of the other clones of Galen Marek.
Later, during his campaign against the New Republic, Grand Admiral Thrawn used ysalamir to "push back" the Force around the Spaarti cloning cylinders he was using to create an army. By doing this, Thrawn was able to grow an adult Human clone in twenty days, but with no risk of clone madness.
- Star Wars: The Force Unleashed II
- Star Wars: The Force Unleashed II novel
- Star Wars: The Force Unleashed II comic
- Heir to the Empire (First appearance)
- Dark Force Rising
- The Last Command