Neuroscience of Schizophrenia: Simplified

What’s going on in the brain behind schizophrenia?

While psychotic disorders are complex conditions that we still don’t know everything about, there are certain neuroscience concepts that I’ve summarized to help better explain what we do know. Understanding how the brain influences behavior allows us insight on the complexity of the human experience. This understanding can also help diminish stigma surrounding serious mental illness.

What is Psychosis?

Psychosis is a mental state of detachment from reality. This detachment can involve delusions (i.e., false beliefs ) and/or hallucinations (i.e., perceiving things that are not there). In people who experience chronic psychosis, they may present with unusual, inappropriate, potentially harmful behaviors. Their speech may be incoherent, illogical, or bizarre. They also may exhibit “negative symptoms,” or diminished functioning such as motivation, speech ability, and social interactions.

What is Schizophrenia?

Schizophrenia is a chronic psychotic disorder that involves significant functional impairment. To be diagnosed with schizophrenia, one must exhibit 2 or more of the following symptoms, with at least one being delusions, hallucinations, or disorganized speech. An individual must show significant functional impairment (e.g., socially, occupationally, with self-care), and these criteria must be met for a continuous period of at least six months:

  1. Delusions: These are false beliefs, such as being harmed or harassed, having exceptional ability or fame, another person being in love with you, or that a major catastrophe is about to occur.
  2. Hallucinations: These can involve any of the senses, but typically involve seeing or hearing things that don’t exist.
  3. Disorganized speech: Effective communication is impaired, and answers to questions may be partially or completely irrelevant. Sometimes disorganized speech may include meaningless words.
  4. Extremely disorganized or abnormal behavior: This can take various forms such as: childlike playfulness, unpredictable agitation, inappropriate gestures, excessive movement, or a complete lack of response.
  5. Negative symptoms: These refer to a diminished ability, or incapacity, to function normally. For example, the following may be impaired: emotional expression, personal hygiene, motivation, interest, or social skills.

Risk Factors

Various factors can make one more vulnerable to developing schizophrenia, such as:

  • Family history of schizophrenia
  • Pregnancy and birth complications, such as malnutrition, exposure to toxins, or viruses that affect brain development
  • Psychoactive drug use as a teenager and young adult

Phases of Schizophrenia

Understanding the progression of schizophrenia can aid in determining the most effective treatments and interventions. As shown below, the onset of this mental illness is typically in early adulthood, and treatment becomes increasingly critical. While there is no cure for schizophrenia, it can be treated with medication, supportive services, and counseling.

The onset of schizophrenia is typically in early adulthood.

Schizophrenia and Dopamine

Dopamine is a neurotransmitter, or chemical messenger, that is involved in processes such as pleasure, learning, movement, motivation, and memory. Dopamine is also heavily involved in schizophrenia. Most of your dopamine is generated deep in the midbrain and released in three pathways across the brain as shown below.

Serotonin, a neurotransmitter involved with mood regulation, may also be implicated in schizophrenia. An imbalance of dopamine and serotonin can manifest in the following ways:

  • Mesocortical Pathway: LACK of dopamine
    • Outcome: impaired cognition, inhibition, motivation
  • Mesolimbic Pathway: EXCESS of dopamine
    • Outcome: fear, delusions, hallucinations
  • Serotonin: EXCESS activity may contribute to symptoms

Antipsychotic Medication

Medications are essential in the treatment of schizophrenia, and antipsychotic medications are the most commonly prescribed drugs. Antipsychotic medications are used to manage symptoms at the lowest possible dose, and control symptoms by affecting neurotransmitter levels. It can take several weeks to notice an improvement in symptoms.

First-Generation Antipsychotics (FGAs)

“Conventional,” or “first-generation,” antipsychotics (FGAs) act by blocking excess dopamine in the brain. However, they can cause serious side effects and are ineffective in treating negative symptoms (e.g., diminished normalcy in speech and emotional expression). Some FGAs, with their common brand names, are listed below:

  • Haloperidol (Haldol)
  • Chlorpromazine (Thorazine)
  • Fluphenazine (Prolixin)
  • Perphenazine (Trilafon)

The inefficiencies of FGAs led to a new series of medication known as “second-generation” antipsychotics (SGAs).

Second-Generation Antipsychotics (SGAs)

Previously referred to as “atypical,” SGAs have shown improved outcomes when compared to FGAs as they treat a wider range of symptoms and have fewer side effects. These medications are typically the first line treatment for schizophrenia and other psychotic disorders. They work in the brain by blocking excess dopamine and serotonin. Some SGAs, with their common brand names, are listed below:

  • Risperidone (Risperdal)
  • Quetiapine (Seroquel)
  • Olanzapine (Zyprexa)
  • Ziprasidone (Geodon)
  • Aripiprazone (Abilify)

Treatment Adherence

The treatment provider may try different medications or doses over time to achieve a desired result. Because medications for schizophrenia can cause serious side effects, individuals may be reluctant to take them. In addition to receiving medication, treatment for schizophrenia often includes mental health counseling and supportive services that can foster stability in different domains of an individual’s life.

Photo by agsandrew on iStock

Challenges of Schizophrenia

Left untreated, schizophrenia can contribute to severe problems such as:

  • Financial problems and homelessness
  • Suicidal ideation and suicide attempts
  • Comorbidity mental illnesses
  • Substance abuse as self-medication
  • Inability to work or attend school
  • Social isolation
  • Being victimized
  • Health and medical issues

The functional impairment that can occur in different domains of a person’s life contributes to stigma surrounding those with schizophrenia and psychotic disorders. Individuals with untreated schizophrenia can easily become “social outcasts” and fall further into the disease.

Conclusion

Schizophrenia is a chronic mental illness that involves psychosis and functional impairment. While it’s uncommon in the general population, there are factors that can predispose one to developing this disease. Neurologically, as it can be caused by imbalances of dopamine and serotonin, antipsychotic medication improves symptoms by restoring the balance of these neurotransmitters. Also, as schizophrenia can affect multiple domains of a person’s life (e.g., social, occupational, medical), treatment that involves medication, counseling, and supportive services are extremely important. Understanding how the brain influences behavior allows us insight on the complexity of the human experience. This understanding can also help diminish stigma surrounding serious mental illness.

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