According to the National Institute of Mental Health, about 2.4 million American adults have some form of schizophrenia, a disorder that affects perception of reality.
Schizophrenia subtypes include:
- paranoid, which causes people to believe they are being singled out for harm
- disorganized, which causes garbled speech and thought patterns and frequently causes the inability to handle basic daily activities (bathing, dressing appropriately for the weather) by oneself
- catatonic, which ranges from the inability to move or speak on one extreme to being overly excitable (frenzied pacing, walking in circles) for no obvious reason on the other
- undifferentiated, in which symptoms are not well enough defined to permit classification into one of the other categories
- residual, when the illness is no longer in an acute phase.
Schizophrenia symptoms generally first appear between ages 16 and 30, though men can have symptoms — such as hallucinations and delusions — before women do. Auditory hallucinations, in which sufferers hear voices in their heads, and unrealistic beliefs, such as possession of superpowers, are most common.
Schizophrenia also can affect cognition. For example, disorganized thinking can make it hard to connect thoughts logically. Other cognitive symptoms include problems with attention and working memory.
The exact cause of schizophrenia is unknown, though genetics and environmental factors may play a role. For example, altered brain structures, such as having less gray matter than average, may contribute to the onset of the disorder. Altered brain chemistry, specifically due to the neurotransmitter dopamine, also may be a factor.
The Dopamine Theory of Schizophrenia
Pharmacological treatments support the idea that an overactive dopamine system may result in schizophrenia: Medications that block dopamine receptors, specifically D2 receptors, reduce schizophrenia symptoms.
The brain regions known as the thalamus and the striatum are affected by dopaminergic activity. Manzano et al. explain that schizophrenia results in altered levels of D2 binding potential in those two regions of the brain. For example, the authors note that schizophrenia patients who do not take antipsychotic medications have a lower thalamic D2 binding potential. In addition, untreated schizophrenia patients have a higher number of D2 receptors in the striatum.
Creativity and Schizophrenia
Divergent thinking, which affects the way individuals arrive at ideas, also is affected by dopaminergic activity, according to Manzano et al. For example, when testing divergent thinking, participants are given an object, such as a stone, and asked different ways that it could be used. More creative people come up with more uses for the object.
To investigate D2 receptor density in non-schizophrenics, the authors used six men and eight women who had no history of psychological or neurological disorders. However, one participant scored extremely low on the Raven’s Standard Progressive Matrices Plus, which measures cognitive ability, and was excluded from the results. Divergent thinking was tested with the Berliner Intelligenz Struktur Test (BIS), which uses figures, verbal and numerical factors to test for creativity. The authors also scanned the participants’ brains, using magnetic resonance (MR) and position emission tomography (PET), with the thalamus, frontal cortex and striatum as regions of interest.
After gathering the data, the authors compared the D2 binding potentials in the regions of interest to the results from the BIS and Raven. The results of the study showed a significant negative correlation between divergent thinking and D2 receptor binding potentials in the thalamus, but not in the striatum. They also found that intelligence is separate from divergent thinking. More creative people had a lower D2 receptor density in their thalamus, like patients with schizophrenia.
So how do schizophrenia and creativity relate? Since both creative people and schizophrenics have fewer D2 receptors in the striatum, the authors suggest that their brains do not filter out as much information as other people’s brains do. For creative people, this means they can come up with solutions and ideas that other people may not. With schizophrenics, it may result in their abnormal thought process that occurs with the psychotic symptoms of the disorder. While the mechanisms of schizophrenia are not fully known, this finding on the connection between dopamine and creativity provides insight into the symptoms of schizophrenia.
Manzano, O. et al. “Thinking Outside a Less Intact Box: Thalamic Dopamine D2 Receptor Densities Are Negatively Related To Psychometric Creativity in Healthy Individuals.” PLoS ONE, May 2010.