Why is it considered too simplistic to say that disorders like depression are caused by little serotonin or schizophrenia much dopamine?

It is considered overly simplistic to attribute disorders like depression solely to low serotonin or schizophrenia solely to high dopamine due to several reasons:

Neurotransmitter interactions: The brain is a complex organ, and mental disorders are influenced by numerous neurotransmitters and their interactions. Serotonin and dopamine are crucial, but they do not operate in isolation. The oversimplified "low serotonin equals depression" or "high dopamine equals schizophrenia" narrative overlooks the intricate interplay between various neurotransmitters, receptors, and neural pathways.

Individual variability: Individuals have variable responses to neurotransmitter levels. Some people with low serotonin may not develop depression, while others with normal or even elevated levels may still experience it. Similarly, dopamine dysregulation can manifest differently in different people.

Multiple contributors: Mental disorders often result from a complex combination of genetic, biological, environmental, psychological, and social factors. While neurotransmitter imbalances may be part of the picture, they rarely act in isolation. Factors like genetics, stress, trauma, inflammation, and drug use can all contribute to the development of psychiatric conditions.

Diagnostic complexity: Mental health disorders are diagnosed based on clusters of symptoms and a comprehensive evaluation. While certain neurotransmitter imbalances may sometimes correlate with specific disorders, they alone are insufficient for diagnosis. Accurate diagnosis and treatment require a thorough assessment that considers various factors.

Unidimensional view of treatment: The view that mental health disorders can be boiled down to a single neurotransmitter imbalance can lead to an overreliance on medications that target specific neurotransmitters, like selective serotonin reuptake inhibitors (SSRIs) for depression. While medication can be beneficial, effective treatment often involves a holistic approach that includes psychological therapies, lifestyle modifications, and other interventions.

In summary, mental health disorders are complex conditions that involve multiple interacting factors, and it is an oversimplification to attribute their causes solely to levels of specific neurotransmitters like serotonin or dopamine.