In this guide, we will discuss the negative symptoms of schizophrenia. 

Negative symptoms of schizophrenia

Negative symptoms of schizophrenia include blunting affect, poverty of speech and thought, apathy, anhedonia, reduced social drive, loss of motivation, lack of social interest and inattention to social or cognitive input. 

Negative symptoms are said to be the major contributors to the low level of functioning and they can become very disabling for most people suffering from schizophrenia. Additionally, low levels of motivation are said to be the reason why most people with schizophrenia cannot function adequately at school, work or other daily life activities.

Moreover, relationships with relatives and friends are very difficult to maintain since they show having an unresponsive affect and inattention to social cues.  “Personal interests yield to the dampening influences of anhedonia, apathy, and inattention (mdedge.com).”

Psychosis is the most common cause of hospital admission, the primary line of treatment (an antipsychotic medication) which is meant to eliminate or even significantly reduce the symptoms. However, controlling the symptoms can be effective in reducing the probability of hospitalizations, patients’ functional capacity improves only minimally as psychosis abates and negative symptoms still tend to persist.

Psychiatrists face some challenges when treating negative symptoms, therapeutic response, pervasiveness of the symptoms, and a considerable diminution of schizophrenia sufferers quality of life. 

Importance of negative symptoms

Schizophrenia spectrum is considered a heterogeneous disorder that is characterized by positive, negative, cognitive, and mood symptoms. “The relative severity of these four pathologic domains varies from case to case and within the same individual over time (mdedge.com).”

Even though, these domains are related, they actually have different underlying mechanisms and are differentially related to functional capacity and quality of life. Additionally, they have different patterns of response to treatment. While positive symptoms refer to symptoms such as delusions, hallucinations, suspiciousness, disorganized thinking, in contrast negative symptoms represent a disruption in normal functioning. 

As we have mentioned, negative symptoms include blunting of affect, poverty of speech and thought, apathy, anhedonia, reduced social drive, loss of motivation, lack of social interest, and inattention to social or cognitive input (mdedge.com). 

From negative symptoms to positive symptoms

Some researchers have considered negative symptoms to represent the fundamental aspect of schizophrenia. However, it was not always like that, since over the course of a few years, the importance of negative symptoms was progressively downplayed. Positive symptoms were increasingly emphasized because (mdedge.com):

• positive symptoms have a more dramatic and easily recognized presentation
• negative symptoms are more difficult to reliably define and document
• Antipsychotics, which revolutionized schizophrenia treatment, produce their most dramatic improvement in positive symptoms.

Relationship between the brain and negative symptoms

Research has described how brain chemistry and malfunction seems to be a contributing factor to developing schizophrenia. However, it is said that schizophrenia affects the interaction between the centers of judgement and planning in the pre-frontal cortex and the centers of emotion and memory in the temporal lobes and limbic system (health.harvard.edu). 

One of the theories for schizophrenia indicates that the brain’s noise level rises when the excitatory neurotransmitter glutamate becomes overactive in the prefrontal cortex and at the same time stimulates receptors for another neurotransmitter, dopamine, in the limbic region (health.harvard.edu). 

In accordance with this theory, glutamate activity seems to result in the manifestation of negative and cognitive symptoms (apparently as a defence against the noise), and psychotic symptoms seems to be a result of dopaminergic activity in the limbic system. 

The reward circuits are said to be located in the limbic system, this is why patients with schizophrenia are said to have a malfunction in their reward system when they seem to want too little, related to volition. This is why the original antipsychotic drugs targeted the nerve receptors in the limbic system, suppressing the activity of the neurotransmitter dopamine. 

Since the 80s, a new generation of drugs emerged where it is said that they did act on the brain in different and more varied ways than the previous generation, psychiatrists hoped for the relief of negative as well as positive symptoms. However, the results were very disappointing and no drug available is specific for the treatment of schizophrenia.  

According to health.harvard.edu, “All of them are roughly equally good at suppressing psychotic symptoms and equally ineffective against negative symptoms — whether the source of these symptoms is schizophrenia or another disorder.”

As of today, there is no existing drug treatment specific to treating negative symptoms. However, some approaches involves stimulation of the NMDA receptor, which regulates the release of glutamate in the prefrontal cortex. 

Research on the negative symptoms of schizophrenia

In a study from 2016, researchers attempted to summarize the most important concepts with regard to negative symptoms in schizophrenia. They explain how research has focused on the concept of negative symptoms which were subsequently introduced to psychiatry to describe this phenomenon. 

Negative symptoms are said to signify a significant loss of function where there can be theoretically speaking, a large amount of potential negative symptoms.  According to the researchers “given the variety of cognitive, emotional, and socio-occupational deficits seen in schizophrenia, excepting defects in the domain pertaining to emotion, the rest are not defined as negative symptoms.” 

According to the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition – Text Revision (DSM) and DSM-5, the list and definition of negative symptoms can be found under Criterion A5. Affective flattening, alogia (poverty of speech), and avolition (an inability to initiate and persist in goal-directed activities) have been included in the definition of schizophrenia.

Other symptoms such as anhedonia (loss of the ability to find or derive pleasure from activities or relationships) have been described as associated symptoms. The other international classificatory system, International Classification of Diseases (ICD-10),[8] enlists “marked apathy, paucity of speech, and blunting or incongruity of emotional responses” as negative symptoms. 

The National Institute of Mental Health Measurement and Treatment Research to Improve Cognition in Schizophrenia consensus panel has recently defined five negative symptoms:[9] blunted affect (diminished facial and emotional expression), alogia (decrease in verbal output or verbal expressiveness), asociality (lack of involvement in social relationships of various kinds), avolition (a subjective reduction in interests, desires, and goals and a behavioral reduction of self-initiated and purposeful acts), and anhedonia (inability to experience pleasure from positive stimuli). The current DSM-5 describes negative symptoms as “restricted emotional expression and avolition.” The first term includes reduction in expressions of emotion “in the face, eye contact, intonation of speech (prosody), and movements of the hand, head, and face that normally give an emotional emphasis to speech.”[7] Avolition has been defined as “a decrease in motivated self-initiated purposeful activities.” Certain other negative symptoms have been mentioned and defined in the current system and include alogia, anhedonia, and asociality.

While working with the negative symptoms in schizophrenia, it was recognized early that they might originate secondary to a lot of conditions, some related directly and others indirectly to the disease under study. These included long-term institutionalization, lack of environmental stimuli, poor social support, secondary to positive symptoms, other psychiatric illnesses as depression, and exacerbations of the disease as such and even antipsychotic medications.[10] As primary negative symptoms tend to be chronic, frustrating, and extremely debilitating, this “secondary origin” is important to recognize for the simple reason of potential treatability of a number of these. Both ICD-10 and DSM-5 require the clinician to rule out the secondary causes before concluding on this. DSM-5 recommends a persistence of the symptoms for a “considerable period” of time in spite of directed efforts at resolving the underlying secondary causes to be a reliable indicator for the primacy of the negative symptoms.

Under the present classificatory systems, schizophrenia remains the only disorder described along with negative symptoms. Perhaps, this approach is rooted in history because, while describing disordered volition in patients with dementia praecox, Kraepelin[1] had simultaneously noted, and emphasized upon, an absence of this in manic-depressive psychosis. As the current evidence gradually blur the once-distinct boundary between the two entities, the exclusivity of negative symptoms in schizophrenia is questioned.

How to measure negative symptoms

During the 1970s and 1980s, psychiatry saw the introduction of a number of scales specially prepared to measure negative symptoms. The major scales included the SANS,[19] PANSS,[4] Brief Psychiatric Rating Scale,[20] and the Schedule for the Deficit Syndrome (SDS).[21]

A detailed discussion of the individual scales will not be considered here further, and the readers are referred to the respective references. However, a few salient points need to be mentioned in this discussion. First, while a number of dimensions were measured using these scales in an overlapping manner, they differed in defining these dimensions and thus exclusivity of definitions to symptoms remained questionable.[17] Furthermore, not all of these were meant primarily for measuring negative symptoms and rightly deviated from the same. While SDS measured the presence or absence of deficit syndrome, its utility for negative symptoms remained contentious. Similarly, later studies showed an overlap in domains measured on the subscales of PANSS, thus defining passive social withdrawal (N4), emotional withdrawal (N2), poor rapport (N3), active social avoidance (G16), lack of spontaneity (N6), blunted affect (N1), and disturbance of volition (G13) as actually measuring negative symptoms, rather than the negative symptom subscale itself.[22] Out of all of these, the SANS had been proposed to be the most comprehensive of all,[9] but a few of its subitems such as attentional impairment and inappropriate affect have been questioned for their inclusion in the definition of negative symptoms[23] subsequently.

Recent researchers have developed a number of scales to measure the negative symptoms. These include the brief negative symptoms scale – a 13-item instrument that measures under six subscales of anhedonia, distress, asociality, avolition, affective blunting, and alogia[24] and the Clinical Assessment Interview for Negative Symptoms that measures motivation, pleasure, and emotional expression.[25] The major limitation of these instruments is that they lack the extensive and time-tested validation of their older counterparts.

Frequently asked questions (FAQs) about negative symptoms of schizophrenia

References

Mdedge.com

Health.harvard.edu