The emergence of primary negative symptoms: relevance of timing?

Negative symptoms are an important symptom dimension in schizophrenia that are often least responsive to antipsychotic medications. We revisit the current practice of identifying 'primary' negative symptoms and suggest that its concept would benefit from a further elaboration of their timing of emergence in relation to the dynamic neurobiological changes to enhance their utility in clinical decision-making and research.

EPA guidance on assessment of negative symptoms in schizophrenia

Background

During the last decades, a renewed interest for negative symptoms (NS) was brought about by the increased awareness that they interfere severely with real-life functioning, particularly when they are primary and persistent.

Methods

In this guidance paper, we provide a systematic review of the evidence and elaborate several recommendations for the conceptualization and assessment of NS in clinical trials and practice.

Results

Expert consensus and systematic reviews have provided guidance for the optimal assessment of primary and persistent negative symptoms; second-generation rating scales, which provide a better assessment of the experiential domains, are available; however, NS are still poorly assessed both in research and clinical settings.

This European Psychiatric Association (EPA) guidance recommends the use of persistent negative symptoms (PNS) construct in the context of clinical trials and highlights the need for further efforts to make the definition of PNS consistent across studies in order to exclude as much as possible secondary negative symptoms. We also encourage clinicians to use second-generation scales, at least to complement first-generation ones.

The EPA guidance further recommends the evidence-based exclusion of several items included in first-generation scales from any NS summary or factor score to improve NS measurement in research and clinical settings. Self-rated instruments are suggested to further complement observer-rated scales in NS assessment.

Several recommendations are provided for the identification of secondary negative symptoms in clinical settings.

Conclusions

The dissemination of this guidance paper may promote the development of national guidelines on negative symptom assessment and ultimately improve the care of people with schizophrenia.

Current perspectives in treating negative symptoms of schizophrenia: A narrative review (Review)

The negative symptoms of schizophrenia are an unmet treatment target as currently approved treatments mostly control positive symptoms. The persistence of these symptoms holds back the patient's reinstatement in society, making them incapable of fulfilling their social, professional, or family roles. There is overwhelming research evidence suggesting that the negative symptoms of schizophrenia are associated with poorer functioning and lower quality of life than positive symptoms, confirming the need for developing new treatments for this particular category of symptoms. This present review aims to review clinical trials addressing novel pharmacological approaches addressing primary negative symptoms of schizophrenia. We overview both monotherapies, first-generation and second-generation antipsychotics, and add-on therapies, including psychostimulants, anti-inflammatory drugs, antidepressants, molecules targeting glutamatergic, cholinergic or serotonergic systems and hormones. Our findings suggest that the primary negative symptoms of schizophrenia may be mitigated by adjunctive therapies, and we highlight the pharmacological agents that have proven superior efficacy. Novel compounds such as cariprazine and MIN-101, to date, show promising results, but large clinical trials are needed to test their efficacy and safety.

Primary and Secondary Negative Symptoms in Schizophrenia

The negative symptoms of schizophrenia include volitional (motivational) impairment manifesting as avolition, anhedonia, social withdrawal, and emotional disorders such as alogia and affective flattening. Negative symptoms worsen patients' quality of life and functioning. From the diagnostic point of view, it is important to differentiate between primary negative symptoms, which are regarded as an integral dimension of schizophrenia, and secondary negative symptoms occurring as a result of positive symptoms, comorbid depression, side effects of antipsychotics, substance abuse, or social isolation. If secondary negative symptoms overlap with primary negative symptoms, it can create a false clinical impression of worsening deficit symptoms and disease progression, which leads to the choice of incorrect therapeutic strategy with excessive dopamine blocker loading. Different longitudinal trajectories of primary and secondary negative symptoms in different schizophrenia stages are proposed as an important additional discriminating factor. This review and position paper focuses primarily on clinical aspects of negative symptoms in schizophrenia, their definition, phenomenology, factor structure, and classification. It covers the historical and modern concepts of the paradigm of positive and negative symptoms in schizophrenia, as well as a detailed comparison of the assessment tools and psychometric tests used for the evaluation of negative symptoms.

Resveratrol Adjunct Therapy for Negative Symptoms in Patients With Stable Schizophrenia: A Double-Blind, Randomized Placebo-Controlled Trial

BACKGROUND

Patients with schizophrenia can generally manifest a broad variety of primary negative symptoms. The current study aimed to assess the efficacy and tolerability of resveratrol add-on therapy in the treatment of negative symptoms in patients with stable schizophrenia.

METHODS

In a randomized, double-blind, and placebo-controlled setting, schizophrenia patients were assigned to receive either 200 mg/d resveratrol or matched placebo in addition to a stable dose of risperidone for 8 weeks. Patients were assessed using the positive and negative syndrome scale, the extrapyramidal symptom rating scale, and Hamilton Depression Rating Scale over the trial period. The primary outcome was considered as the change in positive and negative subscale score from baseline to week 8 between the treatment arms.

RESULTS

A total 52 patients completed the trial (26 in each arm). Baseline characteristics of both groups were statistically similar (P  > .05). Despite the statistically similar behavior of positive symptoms between the groups across time (Greenhouse-Geisser corrected: F = 1.76, df = 1.88, P = .180), the resveratrol group demonstrated greater improvement in negative, general psychopathology, and total scores (Greenhouse-Geisser corrected: F = 12.25, df = 2.04, P < .001; F = 5.42, df = 1.56, P = .011; F = 7.64, df = 1.48, P = .003). HDRS scores and its changes, ESRS score, and frequency of other complications were not significantly different between resveratrol and placebo groups.

CONCLUSION

Adding resveratrol to risperidone can exhibit remarkable efficacy and safety in terms of management of schizophrenia-related negative symptoms.

A study on negative and depressive symptom prevalence in individuals at ultra-high risk for psychosis

BACKGROUND

Negative symptoms are known to be present in the prodromal stage of psychotic disorders, yet little is known about their prevalence. Studies examining the presence of negative symptoms in ultra-high risk (UHR) populations have shown some limitations, notably failing to control depression. The objective of this study was to examine the prevalence of negative symptoms in the presence of significant levels of depression and in the absence of such symptoms (primary negative symptoms) over 1 year and to examine differences in negative symptoms in psychosis converters and non-converters.

METHODS

Participants were 123 individuals at UHR for the development of psychosis receiving follow-up for a period of 2 years. Negative symptoms and depression were measured using the Scale for the Assessment of Negative Symptoms and the Montgomery-Asberg Depression Scale at baseline, 6 and 12 months post-admission.

RESULTS

At baseline, the prevalence of negative symptoms and primary negative symptoms was 76.4% and 32.7%, respectively. Whereas the prevalence of negative symptoms was significantly decreased at 6 months, the prevalence of primary negative symptoms was similar at all time points. Negative symptoms at baseline were not different between later converters and non-converters to psychosis.

CONCLUSION

Our findings confirm the presence of secondary and primary negative symptoms in individuals at UHR, but suggest a differential trajectory of both measures over time. Future studies should include larger UHR groups and focus on the investigation of intra-individual changes in primary negative symptoms over time and further explore their potential role for psychosis conversion.

Premorbid academic and social functioning in patients with schizophrenia and its associations with negative symptoms and cognition

OBJECTIVE

The study aimed to explore premorbid academic and social functioning in patients with schizophrenia, and its associations with the severity of negative symptoms and neurocognitive impairment.

METHOD

Premorbid adjustment (PA) in patients with schizophrenia was compared to early adjustment in unaffected first-degree relatives and healthy controls. Its associations with psychopathology, cognition, and real-life functioning were investigated. The associations of PA with primary negative symptoms and their two factors were explored.

RESULTS

We found an impairment of academic and social PA in patients (P ≤ 0.000001) and an impairment of academic aspects of early adjustment in relatives (P ≤ 0.01). Patients with poor PA showed greater severity of negative symptoms (limited to avolition after excluding the effect of depression/parkinsonism), working memory, social cognition, and real-life functioning (P ≤ 0.01 to ≤0.000001). Worse academic and social PA were associated with greater severity of psychopathology, cognitive impairment, and real-life functioning impairment (P ≤ 0.000001). Regression analyses showed that worse PA in the academic domain was mainly associated to the impairment of working memory, whereas worse PA in the social domain to avolition (P ≤ 0.000001).

CONCLUSION

Our findings suggest that poor early adjustment may represent a marker of vulnerability to schizophrenia and highlight the need for preventive/early interventions based on psychosocial and/or cognitive programs.

Citicoline (CDP-choline) add-on therapy to risperidone for treatment of negative symptoms in patients with stable schizophrenia: A double-blind, randomized placebo-controlled trial

OBJECTIVE

We aimed to evaluate the efficacy and tolerability of citicoline add-on therapy in treatment of negative symptoms in patients with stable schizophrenia.

METHODS

In a double-blind and placebo-controlled study, patients with stable schizophrenia (DSM-5) were randomized to receive either 2,500 mg/day citicoline or placebo in addition to risperidone for 8 weeks. The patients were assessed using the positive and negative syndrome scale (PANSS), the extrapyramidal symptom rating scale (ESRS), and Hamilton depression rating scale (HDRS). The primary outcome was the difference in PANSS negative subscale score reduction from baseline to week 8 between the citicoline and the placebo groups.

RESULTS

Sixty-six individuals (out of 73 enrolled) completed the trial. The citicoline group demonstrated significantly greater improvement in negative scores, F(1.840, 118.360) = 8.383, p = .001, as well as general psychopathology, F(1.219, 78.012) = 6.636, p = .008; change in general psychopathology did not remain significant after adjustment, and total PANSS scores, F(1.633, 104.487) = 15.400, p < .001, compared with the placebo. HDRS scores and its changes, ESRS score, and frequency of other side effects were not significantly different between the two groups.

CONCLUSIONS

Citicoline add-on therapy to risperidone can effectively improve the primary negative symptoms of patients with schizophrenia.

Patterns of structural MRI abnormalities in deficit and nondeficit schizophrenia

Negative symptoms of schizophrenia have generally been found in association with ventricular enlargement and prefrontal abnormalities. These relationships, however, have not been observed consistently, most probably because negative symptoms are heterogeneous and result from different pathophysiological mechanisms. The concept of deficit schizophrenia (DS) was introduced by Carpenter et al to identify a clinically homogeneous subgroup of patients characterized by the presence of primary and enduring negative symptoms. Findings of brain structural abnormalities reported by magnetic resonance imaging (MRI) studies focusing on DS have been mixed. The present study included 34 patients with DS, 32 with nondeficit schizophrenia (NDS), and 31 healthy comparison subjects, providing the largest set of MRI findings in DS published so far. The Schedule for the Deficit Syndrome was used to categorize patients as DS or NDS patients. The 2 patient groups were matched on age and gender and did not differ on clinical variables, except for higher scores on the negative dimension and more impaired interpersonal relationships in DS than in NDS subjects. Lateral ventricles were larger in NDS than in control subjects but were not enlarged in patients with DS. The cingulate gyri volume was smaller in NDS but not in DS patients as compared with healthy subjects. Both groups had smaller dorsolateral prefrontal cortex and temporal lobes than healthy subjects, but DS patients had significantly less right temporal lobe volume as compared with NDS patients. These findings do not support the hypothesis that DS is the extreme end of a severity continuum within schizophrenia.