Negative symptoms in chronic schizophrenia. Relationship to duration of illness

Aberrant Frontostriatal Connectivity in Negative Symptoms of Schizophrenia

Negative symptoms represent a distinct component of psychopathology in schizophrenia (SCZ) and are a stable construct over time. Although impaired frontostriatal connectivity has been frequently described in SCZ, its link with negative symptoms has not been carefully studied. We tested the hypothesis that frontostriatal connectivity at rest may be associated with the severity of negative symptoms in SCZ. Resting state functional connectivity (rsFC) data from 95 mostly medicated patients with SCZ and 139 healthy controls (HCs) were acquired. Negative symptoms were assessed using the Brief Negative Symptom Scale. The study analyzed voxel-wise rsFC between 9 frontal "seed regions" and the entire striatum, with the intention to reduce potential biases introduced by predefining any single frontal or striatal region. SCZ showed significantly reduced rsFC between the striatum and the right medial and lateral orbitofrontal cortex (OFC), lateral prefrontal cortex, and rostral anterior cingulate cortex compared with HCs. Further, rsFC between the striatum and the right medial OFC was significantly associated with negative symptom severity. The involved striatal regions were primarily at the ventral putamen. Our results support reduced frontostriatal functional connectivity in SCZ and implicate striatal connectivity with the right medial OFC in negative symptoms. This task-independent resting functional magnetic resonance imaging study showed that medial OFC-striatum functional connectivity is reduced in SCZ and associated with severity of negative symptoms. This finding supports a significant association between frontostriatal connectivity and negative symptoms and thus may provide a potential circuitry-level biomarker to study the neurobiological mechanisms of negative symptoms.

Predictors of 10-year outcome of first-episode psychosis

BACKGROUND

Predictors of outcome for psychosis are poorly understood. Duration of untreated psychosis (DUP) appears to predict short-term outcome although its medium- to long-term role remains unclear. Neurodevelopmental indices such as pre-morbid function and/or neurological soft signs may predict longer-term outcome. We aimed to assess the impact of a range of clinical and demographic variables on long-term outcome of a geographically defined, epidemiological first-episode psychosis cohort.

METHOD

A 10-year follow-up was undertaken of a consecutively presenting sample of 109 cases of first-episode psychosis aged 16-50 years. Baseline assessments included positive, negative and depression symptoms, DUP, neurological soft signs and pre-morbid functioning. Multi-dimensional outcomes were assessed blind to baseline data.

RESULTS

All participants were traced at a mean of 10.5 years post-index admission: 11 had died, 10 from non-natural causes. Of the surviving cases, 70% were comprehensively re-assessed by interview. Summary data on the remainder were collected from their family practitioner and chart review. Poor 10-year outcomes were predicted independently by poor pre-morbid functioning, baseline negative symptoms and longer DUP. The same measures, plus neurological soft signs, appeared to predict outcomes in a DSM-IV schizophrenia/schizo-affective subgroup.

CONCLUSIONS

Poor pre-morbid functioning, baseline symptoms, DUP and neurological soft signs at onset independently predict poor long-term outcome in first-episode psychosis.

Schizophrenia: a review of current research and thinking

Schizophrenia is the major mental illness of our time and causes serious disturbances for those with the condition as well as using up significant proportions of scarce health resources. This paper reviews the recent literature on advances in classification, aetiology, epidemiology and treatments. Methodological problems encountered in researching this condition are discussed. Advances in treatments offered for this condition have improved outcomes but whether the patient receives these treatments may depend on what local services are prepared to offer.

The structure of schizophrenic symptoms: a meta-analytic confirmatory factor analysis

To quantitatively review all presently available evidence about the interrelations between positive and negative schizophrenic symptoms, we created an aggregate matrix of the intercorrelations among schizophrenic symptoms by combining data from 28 independent samples using meta-analytic procedures (net bivariate dfs ranging from 683 to 1657). Using confirmatory factor analyses, we then statistically compared four theoretically derived models of the structure of schizophrenic symptoms. Although a three-factor model (Liddle, 1987) best fit the data, results suggest that either more factors or different symptoms are required to account well for the latent structure underlying schizophrenic symptomatology. The nature of such augmented approaches, the opportunities and constraints inherent to multifactorial models, and the limitations of current instruments are discussed.

Executive (frontal) dysfunction and negative symptoms in schizophrenia: apparent gender differences in 'static' v. 'progressive' profiles

BACKGROUND

While executive (frontal lobe) dysfunction appears to be a core feature of schizophrenia, its relationship to psychopathology, age and duration of illness has yet to be explored systematically between the genders.

METHOD

Executive dysfunction, positive and negative symptoms were evaluated in 27 male and 21 female in-patients who were unusually well-matched on numerous demographic and clinical measures.

RESULTS

Measures of executive dyscontrol and negative symptoms were highly associated in both genders. However, while both executive dyscontrol and negative symptoms increased prominently with age/ duration of illness among women, no such relationship was evident among men.

CONCLUSIONS

The similarly prominent levels of current executive dyscontrol and negative symptoms in male and female patients appear to have emerged via processes that differ fundamentally between the genders; among males these deficits appear to emerge and become 'locked in' earlier in the course of illness and to show little subsequent increase, while among females these same deficits appear to be less evident early in the course but to increase in prominence thereafter.

Symptoms in schizophrenic syndromes in relation to age, sex, duration of illness and number of previous hospitalizations

In studies by means of the Swedish version of the Positive and Negative Syndrome Scale, we have demonstrated a 5-factor model of schizophrenia, including positive, negative, excited, anxious/depressive and cognitive factors. In this study, the 5 factors were correlated with background factors in a series comprising 140 patients with schizophrenic syndromes. None of the 5 factors revealed any significant age or sex differences. The positive factor correlated positively with the number of previous hospitalizations and the negative factor correlated negatively. The excited factor correlated negatively with age at onset, age at first hospitalization and positively with the duration of the illness and the number of previous hospitalizations. The cognitive factor correlated negatively with age at onset and age at first hospitalization and positively with the duration of the illness. Age at onset was positively correlated with delusions, excitement, unusual thought content and poor impulse control and negatively with lack of spontaneity. The duration of illness correlated positively with excitement, difficulty in abstract thinking and mannerisms. The number of previous hospitalizations correlated positively with delusions, excitement, unusual thought content and poor impulse control and significant negative correlations were demonstrated as concerns blunted affect and lack of spontaneity.

Central D2 receptors and negative symptoms of schizophrenia

Most in vivo studies of striatal D2 receptor (SD2R) density with positron emission tomography in schizophrenia have attempted to relate this variable to the diagnosis of the illness. In the present study, a relationship between SD2R and clinical dimensions of this psychosis was searched for in a highly selected group of young negative schizophrenics (8 drug-naïve and 2 drug-free). The SD2R density index measured in vivo using 76Br-bromolisuride and PET correlated negatively (r = 0.80, P < 0.01) with a psychomotor dimension of schizophrenia involving blunted affect and alogia. The mean SD2R index of the patients did not differ from that of age-matched control subjects. Therefore, this behavioural dimension accounts for the variance of the SD2R, suggesting that the striatal dopamine system modulates symptoms such as flattened affect and alogia.

Positive and negative symptoms in families with schizophrenia

Positive and negative symptoms are measurable characteristics that may represent core features of schizophrenia and offer a quantitative approach for studying the genetics of schizophrenia and related disorders. The Positive and Negative Syndrome Scale (PANSS) was used to assess 72 members of five families segregating schizophrenia. The study confirmed high internal reliability of PANSS scales in this sample with diverse lifetime diagnoses. Gender but not alcoholism affected scores. Schizophrenia/schizoaffective and schizophrenia spectrum disorder groups had higher mean scores for the positive and negative scales than other lifetime diagnostic groups, consistent with genetic transmission of these symptoms. Positive and negative symptom patterns did not subtype families. The results support the validity of positive and negative symptom measures as independent dimensions in familial schizophrenia.