Super interesting question!! I think it's PTSD plus depression for what he went through when he was younger (childhood s3xual trauma and abandonment). These traumas can leave deep wounds in the mind and cause significant problems in relationships and s3ssuality in adulthood, as well as mental health problems such as posttraumatic stress disorder, borderline personality disorder and depression.
Yes! I thought PTSD and depression too, I thought maybe bpd cause he is prone to impulsive acts, physical and sexual violence, and the whole self sabotaging of getting horrible "partners" cause he doesnt know what a good partner is and prolly believes he doesnt deserve a good one (/TДT)/
They way the author portrays him with very human qualities, is just incredible
Are there any psych majors reading this? What would Yashiros mental diagnosis be? PTSD, Narc, BPD (I have no idea)? Would love to hear your thoughts