Rick Sanchez is the main protagonist in Adult Swim series Rick and Morty. Fans love his reckless, nihilistic attitude and pessimistic outlook on life; his mental illness plays a key part of his character development as it motivates many of his irrational behaviors and impulses.
Rick does not explicitly state in the show, but there are numerous indications he fits on the autism spectrum. One is his fondness of role-playing - something many individuals on the spectrum also enjoy doing - as one way he finds comfort and belongingness in different characters, such as robots. Other signs could include his obsessive interests and tendency to avoid social interactions - both are classic characteristics of autism spectrum disorder.
Rick suffers from both autism and several mental health conditions. These include depression, which often leads him to withdraw from those he cares for and have negative thoughts and feelings, paranoia (causing him to act irrationally), and paranoia, whereby people might try and harm him.
Rick is an excessive substance user, which has potentially disastrous repercussions for both his physical and mental wellbeing. He often turns to alcohol or drugs in an attempt to cope with his problems; unfortunately this often leads to reckless decisions and behavior.