Yes- his behavior, interviews/own words, history, as well as friends that describe his behavior as a child and young teen. Adana displays many characteristics of a Sociopath (also known as Anti-Social PD and falls into the Reputation-Defending Subtype).
• Lack of empathy – Inability to feel sympathy for others or to understand the emotional consequences of their actions
Not only did he murder Hae with his bare hands and then boast about it to Jay, but he has taken everyone on this journey in attempting to have him set free. He obviously has no regard for his family, his community, the people donating money to his appeal, and their financial and emotional investment in carrying on with this. He has lead listeners of Serial, Rabia/Saad, Susan Simpson, The Innocence Project, Sarah Koening, and everyone else involved on this wild goose chase and wasted their time, resources, and money. It's an awful betrayal to those believing in him, and it's despicable.
• Cold, calculating nature – The ability and willingness to use others around them to personal gain
See above, as well as Hae's murder, using Jay, Rabia for her connections law license and persistence, Saad everyone. There are many many smaller examples of this but I don't want to get into them all. A specific example of what I am referring to is when he calls the police the day Hae's body is found (ostensibly to glean info) but is too distraught to speak so he hands the phone off to Krista- both calculating this to not put himself in front of the police and using her.
• Shallow emotions – Lack of real emotion in response to events, limited capacity to feel love
All of his conversations with Sarah where glib and unemotional for such a sad experience. His is easily outraged by trivial issues presented by Sarah, yet appears unmoved and cold in regards to Hae's murder and justice for this so called person at large that committed it.
• Charming – While the sociopath is unable to fully understand the emotions of others, they are capable but rather highly adept at mimicking them and might appear to be charming and normal at first. They appear to be charming, yet are covertly hostile and domineering
Adnan is superficially charming and attempts to appear "normal"; he even uses this word "normal" over and over in attempting to describe the day Hae went missing, another example of his shallow emotions. We see his covert hostility anytime Sarah attempts to pin him down and challenge him- you can even hear the change and hostility in his voice that she dares to do so.
• High IQ – Often sociopaths will exhibit a high IQ which they can use to manipulate and plan
I think everyone can agree Adnan is intelligent
• Manipulative – Sociopaths use their superficial charm and high IQ to manipulate others to get their ends, and their lack of empathy allows them to do this with no sense of guilt or remorse
This goes back to this ridiculous charade of attempting to manipulate everyone around him with this farce of his innocence.
• Secretive – Has little need for others and is highly secretive in their actions meaning
I don't think it's a coincidence Adnan did not have many close male friends. Nor is it a coincidence that he didn't care for his "best friend" Saad much until he realized he could use him and Rabia to advocate for him. People he didn't know until 9th grade, and he hardly knew Rabia at all until he went to prison- she is incredibly "loosey goosey" saying the have known him for 20 years and were close when the majority of that time AS has been in prison and she didn't even know Adnan and Hae were dating until the day AS was arrested, nor did she visit him until after the trial. Furthermore, his entire alibi is incredibly evasive and secretive with this whole "I don't remember" bs.
• Sensitive to criticism (part of Narcisism) – That said, like all narcissists, the sociopath will desire the approval of others and will be highly sensitive to criticisms. They often feel they deserve adulation and admiration of the world and might feel victimized
This has Adnan written all over it and he falls into the "Reputation-Defending" subtype- all he cares about is his reputation. Anytime SK challenged him there was a marked change in his tone and voice and he became passive aggressive that she dared question him. **The closest we ever see Adnan displaying emotions are when he states it "shook me to the core" that people could think he was capable of this and getting angry at Sarah about bringing up his stealing money from the Mosque!!?! It's the closest we get to ANY emotion from Adnan, and of course, it's about himself (as opposed to, oh I don't know, his dead ex girlfriend and her family) and the fragile image he attempts to portray to the world.
• Lawfulness – Despite popular belief, a sociopath is not likely to be a problem to the law in later life, but rather will seek to find loopholes, to rise to a position of power, or to move to another area so that their behavior is tolerated. However, this is not always the case and we often see delinquency during the juvenile years.
Adnan's entire defense and claim to innocence is not test the DNA, or I am fundamentally innocent. Instead, the more pervasive message is challenge my case, my attorney was ineffective, the prosecution's timeline is not correct, always seeking a loophole to get out of prison. He even admits himself he constantly over explains, anther attempt at loopholes and attempting to rationalize his abnormal behaviors. We also see his disregard for norms and laws in his drug use, stealing, and hanging out with shady characters.
• Compulsive lying – As part of their facade, and as a means to an end, sociopaths are compulsive liars and will rarely speak truthfully making them hard to pin down
Another trait that reeks of Adnan. ALL of his interactions with Sarah are evasive and slippery. He also lied to his family all the time, as well as others about this true feelings as evidenced in Hae's letter and diary as well as his actions. He creates an illusion about his feelings towards Hae, while his real emotions are witnessed in his passiveness, controlling nature, and Hae's diary/letter. He is a compulsive liar just like Jay, only he is MUCH smarter about it and does it by omission and being evasive...so for different reasons. He also lies about his friendship with Jay, among everything else.
In all cases though the psychopath will appear highly intelligent, charming and charismatic to talk to and it is only careful guardedness that can uncover their true motivations.
References: DSM V http://www.healthguidance.org/entry/15850/1/Characteristics-of-a-Sociopath.html