Schizophrenia Jillian Oviedo

According to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, schizophrenia is a "neuropsychiatric disorder with complex genetics and a clinical course that tends to begin during a predictable stage of development." It is a mental disorder characterized by a split from reality, manifested in delusions, unorganized speech and thought, hallucinations, and inappropriate emotional expressions or lack thereof. Schizophrenia is incredibly complex and heavily biologically-influenced, wherein many small defects in biological processes and functions, as well as in genes, accumulate to produce the symptoms.


  • Schizophrenia afflicts around 1.1% of the global population, and based on estimates from different countries, more than 21 million and up to 51 million people worldwide. Most countries have generally similar schizophrenia rates, from .5% to 1%.
  • Schizophrenia occurs regardless of society, age, ethnicity, culture, religion, though groups of people can vary slightly in incidence and diagnosis.
  • Men are more afflicted than women, and are are thought to be more susceptible to it and have an earlier onset of it at an average of 18 years old compared to 25 years old for women.


Research is being done on the causes as we speak, but so far not one single factor has been identified in causing schizophrenia. In individual case studies, multiple factors contribute to the severity of schizophrenia and its form from person to person

A theory regarding the development of schizophrenia is that the levels of the neurotransmitter dopamine are high, and the dopamine systems and neural networks tend to be hyperactive (dopamine hypothesis). Some studies that have examined the genetic sequences of patients with schizophrenia showed a common mutation present in their genomes: the deletion of the COMT gene, which codes for the creation of a catabolic enzyme in charge of breaking down dopamine. Though that mutation is common, not all schizophrenia patients have it. What's more, there is conflicting data that COMT may not have anything to do with schizophrenia.

Dopamine pathway malfunctions and their relations to schizophrenic symptoms.

Conflicting data points to the role of epigenetics in the onset of schizophrenia, how gene expression is modified rather than any change in the genome itself. Epigenetic factors include some kind of compromise during child birth (lack of oxygen, low weight) and prenatal environment (smoking, drinking, or being ill during pregnancy). Since it is a fairly new idea, there is not enough research and information to make definitive conclusions about the role of epigenetics in schizophrenia.

Some scientists believe that brain chemistry and structure makes certain individuals more predisposed to schizophrenia. For example, the brain undergoes changes during puberty that may bring out psychotic symptoms in some whose brain allows it to. Imbalances in the interrelated chemical reactions of the brain may also play a role. People with schizophrenia have been found to have relatively smaller brains with less grey matter and enlarged ventricles. Compromises to the occipital lobe have been linked to not full-blown visual hallucinations, rather trouble of schizophrenic individuals to interpret complex visual stimuli or recognize movement. In the temporal lobe, the auditory center activates during auditory hallucinations, suggesting trouble for the brain in interpreting auditory stimuli.

The top portion shows brain activity in healthy persons. The bottom portion shows decreased activity in the prefrontal cortex of a patient with schizophrenia, an area vital to judgment and decision-making.

Epidemiological studies have shown that it is a heritable disease, confirmed by an agreement rate of 60-70% of monozygotic (identical) twin studies. If an individual's parents have schizophrenia, their chances of developing it are dramatically higher than those whose parents do not. The more schizophrenic relatives one has, the more likely that individual will develop schizophrenia.

The brain scan reveals enlarged ventricles and less grey matter in the schizophrenic twin


It is a long-term illness as well as a spectrum. Signs can be present throughout childhood and early childhood and depending on their family history, but it ultimately is difficult to discern. If the mother has severe schizophrenia, chances are much higher for her offspring to develop schizophrenia as well. First detection is difficult as most patients have not had a previous episode or history of psychosis before the first episode. The incidence of episodes often decreases over a life time, and a stressful environment or not taking medications increases the psychotic episodes' incidence and severity. The symptoms and what forms they take as well as their debilitating effects vary widely among schizophrenic individuals, but they fall into several categories.

  • Positive symptoms: The presence of feelings or behaviors appropriate for the situation, including delusions (false beliefs) of grandeur (being rich or a genius), persecution (harm is certain to come), or reference (believing events have to do with oneself); hallucinations such as hearing voices or seeing bizarre phenomena and other false sensory experiences; paranoia and/or exaggerated behaviors
  • Negative symptoms: The absence of feelings of behaviors appropriate for the situation, such as remaining motionless for ours and irritable afterwards (catatonia); lack of emotions (such as indifference when faced with death of a person)
  • Disorganization: Disorganized speech that is not sensible (word salad), confused train of thought; bizarre behavior and abrupt movements
  • Impaired cognition: Problems with attention, memory, and concentration.
Brain scan showing increased cerebral blood flow during auditory and visual hallucinations.
Schizophrenia is a spectrum. Here are some of the different types


Schizophrenia has been found to start between 16 and 30 years old, earlier for men and later in women. The early phase is quite mild and may include bipolar disorder, anxiety, poor concentration, sleep troubles, depression, and social isolation. It lasts for bout 2 to 5 years until the individual develops positive symptoms, wherein the next phase begins: the psychotic phase. These symptoms tend to occur in episodes of varying length and severity. From the psychotic phase, schizophrenia can progress in several ways:

  1. Experience psychotic symptoms with some negative symptoms in between episodes
  2. No residual negative symptoms in between episodes
  3. Continuous psychotic symptoms
  4. One episode with no other symptoms
  5. One episode with some ongoing symptoms, such as hearing just one voice, or others that occur much less than in an actual episode

Recent research shows that the progression of schizophrenia gradually significantly damages the brain with time. The earlier the intervention, the better the outlook of a person with schizophrenia.

Paintings of cats depicting descent into more severe schizophrenic episodes. Done by Louis Wain, a schizophrenic artist during the 1900s


It is not impossible for people with schizophrenia to live normal lives, so long as they have the resources and receive a lot of emotional and social support from family and friends. Since causes are still unknown, the treatments focus on eliminating the symptoms through...

  • Antipsychotics- can be in pill, liquid, or injections. Most antipsychotics work to reduce some of the symptoms associated with schizophrenia by breaking down dopamine or blocking it from its receptor on the post-synaptic neuron. However done, it works to reduce the dopamine levels and/or its hyperactivity. A side effect of long-term use is tardive dyskinesia, an inability to control certain jaw or face muscles. However, with regular use, only 40% of schizophrenic patients relapse within 2 years compared to 80% for those who discontinue use.
  • Psychosocial treatment- since the onset usually occurs in early adulthood, patients can learn coping skills to address the challenges that come with schizophrenia in everyday life. Chances of relapse decrease with participation in regular psychosocial treatment.
  • Coordinated specialty care- integrates drugs, psychosocial therapies, case management, family involvement, and services to help with education and employment, all aimed at reducing symptoms and improving quality of life


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