When most people think of schizophrenia, they probably focus on the psychotic symptoms classically associated with the disorder. However, psychosis represents just one aspect of schizophrenia’s impact, and people affected by the illness also commonly experience a range of problems collectively known as “negative” symptoms. A new study, published in July 2013 in the journal Biological Psychiatry, helps explain the steep decline in personal motivation that typically stems from these lesser-known aspects of the disorder. The disorder’s “negative” symptoms apparently make affected individuals less capable of accurately judging the amount of effort it takes to achieve specific goals.
The most well known aspects of schizophrenia—hallucinations and delusional thought processes—belong to a larger set of symptoms known as “positive” schizophrenia symptoms. It might seem strange to see psychotic symptoms labeled as “positive,” but this designation isn’t meant to identify anything beneficial. Instead, it’s meant to identify schizophrenia symptoms that add something abnormal to the list of everyday human behaviors and experiences. Additional schizophrenia symptoms that fall into this category include abnormally chaotic or disorganized thought processes, abnormal disruptions or gaps in an individual’s thought processes, the spontaneous production of nonsense words, excessive and pointless body movement, and an unresponsive state called catatonia.
Negative schizophrenia symptoms get their name because they represent an absence of certain aspects of normal, everyday human behaviors and experiences. Common examples of these symptoms include a lack of facial and vocal expressiveness during conversations or interactions, a significantly reduced tendency to respond verbally to social cues, loss of the ability to express pleasure, and loss of the personal motivation necessary to do such things as make plans for the future or follow established plans until they’re completed.
Generally speaking, doctors have a harder time diagnosing the negative symptoms of schizophrenia than they do diagnosing the disorder’s positive symptoms. They also have a relatively hard time accurately diagnosing a third set of schizophrenia symptoms, called cognitive symptoms. The most common examples of these symptoms include a reduced ability to use facts for appropriate decision-making, a reduced ability to use recently acquired memories, and a reduced ability to focus one’s attention. In many instances, doctors only pick up on these symptoms indirectly while diagnosing other aspects of schizophrenia.
The Impact of Poor Motivation
The “negative” lack of motivation associated with schizophrenia can have a major impact on an affected individual’s ability to function well in everyday life, according to the authors of a report published in 2005 in the journal Schizophrenia Bulletin. This is true, in part, because people don’t just rely on personal motivation to make plans and pursue long-term goals. They also use an underlying sense of drive or motivation to do such things as learn new information on a day-to-day basis, assess the appropriateness of their actions and behaviors, and modify those actions and behaviors when they make mistakes or experience unwanted outcomes. Without the drive to do these things, schizophrenic individuals can lose touch with one of the basic grounding factors that orient human beings to social and personal reality.
For quite some time, mental health researchers linked the lack of motivation in people with schizophrenia to the effects of another negative symptom, namely lack of the ability to feel pleasure. However, scientists now know that, while schizophrenics don’t express pleasure with any great frequency, they still retain the biological ability to feel pleasurable sensations. In the study published in Biological Psychiatry, a team of researchers from the University of Maryland School of Medicine sought an alternative explanation for schizophrenia’s characteristic motivation deficit. They did this by measuring schizophrenics’ ability to accurately estimate how much effort it takes to pursue different types of goals.
After comparing a group of schizophrenics heavily affected by the disorder’s negative symptoms with a group of people unaffected by schizophrenia, the study’s authors concluded that negative symptoms essentially alter the mental calculation used to estimate the amount of effort required to reach a goal. In effect, this alteration makes people with negative schizophrenia symptoms lose motivation by placing too much emphasis on the costs of effort and too little emphasis on the rewards that come from attaining goals or fulfilling plans. While the effects of this shifted emphasis can potentially decrease the motivation level of anyone affected by the negative symptoms of schizophrenia, the problem appears most consistently in people with especially prominent forms of these symptoms.