Answer:
Neurotransmitter functioning
genetic
brain
Step-by-step explanation:
According to the biological perspective the biology of a person or organism is responsible for the psychological state of the organism. It focuses on the nature side while dealing with psychology.
So, the main reason of psychological disorders in an organism is due to the:
Neurotransmitter functioning
Genetic
Brain
of the organism.
Personality is not studied as it is a result of all the parts of the body functioning together which results in the personality of the organism.