Autophobia is the name of the anxiety disorder for one who fears being alone.
Other words that may describe a person who doesn't like to be alone:
Lintophobic.
Trypanophobics.
Acrophobic
A person that is afraid of the dark has a nyctophobia
Sensible or a pyrophobic.
Hermit!
demophobic,androphobic
Hermit
Social Anxiety?
A person who laughs alone can be called a "solitarian" or simply someone who enjoys their own company and finds joy in their own thoughts.
The person being defended is referred to as the defendant.
I'm afraid not Nope new person :(