Dopaless

Being sad and taking no pleasure to do any action or activity.
It comes from the term "Dopamine" which is a type of neurotransmitter that plays a role in how we feel pleasure.
People that often feel dopaless are often diagnosed as Attention-Deficit Hyperactivity Disorder (ADHD).

It is estimated that ADHD affects more than 5% of children. Boys are diagnosed with ADHD about twice as much as girls. (Harvard - 2018)