Prevalence and clinical correlates of substance use disorders in South African Xhosa patients with schizophrenia

Purpose

To determine the prevalence of substance use disorders (SUDs) in patients with schizophrenia in a sample from South Africa and compare the clinical and demographic correlates in those with and without co-occurring SUDs.

Methods

Patients with schizophrenia were interviewed using the Xhosa version SCID-I for DSM-IV. We used logistic regression to determine the predictors of SUDs.

Results

In the total sample of 1420 participants, SUDs occurred in 47.8%, with the most prevalent SUD being cannabis use disorders (39.6%), followed by alcohol (20.5%), methaqualone (6.2%), methamphetamine (4.8%) and other SUDs (cocaine, ecstasy, opioids, 0.6%). Polydrug use occurred in 40%, abuse occurred in 13.5%, and 39.6% had at least one substance dependence diagnosis. Significant predictors of any SUD were younger age (41–55 vs. 21–30: OR = 0.7, 95% CI = 0.5–0.9), male sex (OR = 8.6, 95% CI = 5.1–14.6), inpatient status (OR = 1.7, 95% CI = 1.3–2.1), post-traumatic stress symptoms (OR = 4.6, 95% CI = 1.6–13.3), legal (OR = 3.4, 95% CI = 2.0–5.5) and economic problems (OR = 1.4, 95% CI = 1.0–2.0). Methamphetamine use disorders occurred significantly less often in the Eastern compared to the Western Cape provinces. Inpatient status and higher levels of prior admissions were significantly associated with cannabis and methamphetamine use disorders. Post-traumatic stress symptoms were significantly associated with alcohol use disorders. Anxiety disorders were associated with other SUDs.

Conclusion

SUDs occurred in almost half of the sample. It is important for clinicians to identify the presence of SUDs as their presence is associated with characteristics, such as male sex, younger age, inpatient status, more prior hospitalisations, legal and economic problems, PTSD symptoms and anxiety.

     

The factor structure for positive and negative symptoms in South African Xhosa patients with schizophrenia

Most studies investigating the symptom dimensions of schizophrenia utilising the Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS) favour a three factor model. This study sought to investigate the factor structure of both the global and individual items of the SANS and SAPS in a large sample of South African Xhosa patients with schizophrenia. A total of 422 subjects participated. Both principal components and factor analytical procedures were applied. For the global items, a two-factor solution representing positive and negative symptoms accounted for 59.9% of the variance. Alternatively, the three-dimensional model of negative, psychotic and disorganisation factors was supported by a five-factor solution if the more heterogeneous items of attention and alogia were ignored. Analysis of the individual items yielded a five-factor solution with the negative symptoms splitting into diminished expression and disordered relating, and the positive symptoms separating into factors for psychosis, thought disorder and bizarre behaviour. Our findings are very similar to those from other parts of the world, providing evidence that the factor structure for the symptoms of schizophrenia is relatively resistant to cultural influences. This is particularly true for negative symptoms.     

Violence in male patients with schizophrenia: risk markers in a South African population

OBJECTIVE: We investigate the role of functional variants in the catecholamine-O-methyl transferase gene (COMT) and the monoamine oxidase-A gene (MOA-A), as well as previously identified non-genetic risk factors in the manifestation of violent behaviour in South African male schizophrenia patients. METHOD: A cohort of 70 acutely relapsed male schizophrenia patients was stratified into violent and non-violent subsets, based on the presence or absence of previous or current violent behaviour. Standardized violence rating scales were also applied and the COMT/NlaIII and MAO-A promoter region variable number of tandem repeats (VNTR) polymorphisms were genotyped. RESULTS: A multiple logistic regression model based on the clinical, genetic and socio-demographic variables indicated that delusions of control (OR = 3.7, 95% CI = 1.21-11.61) and the combined use of cannabis and alcohol (OR = 6.89, 95% CI = 1.28-37.05) were two significant predictors of violent behaviour in this schizophrenia population. No association was found between the tested polymorphisms and violent behaviour. CONCLUSIONS: Although the sample size may have limited power to exclude a minor role for these specific gene variants, such a small contribution would have limited clinical relevance given the strong significance of the non-genetic markers. These findings suggest that currently proactive management of violent behaviour in this schizophrenia population should continue to be based on clinical predictors of violence.     

Emotional responding in deficit and non-deficit schizophrenia

Although emotional dysfunction is presumed to be a central part of the deficit syndrome in schizophrenia, it has not yet been empirically investigated in deficit and non-deficit patients. Emotional responding was examined in 19 male deficit patients, 22 non-deficit patients, and 20 non-patient controls. Patients participated in a semi-structured clinical interview that included questions from the Schedule for the Deficit Syndrome (SDS) and the Brief Psychiatric Rating Scale (BPRS), and then were then categorized into deficit and non-deficit groups. In addition, all participants viewed emotional films while their facial expressions were videotaped and then completed self-reports of emotional experience following each film. As predicted, deficit patients were less expressive than non-deficit patients and controls across the films. Contrary to prediction, deficit patients did not report experiencing less emotion to the films than non-deficit patients or controls. Thus, a disjunction in emotional responding appeared to characterize deficit patients, who were less expressive than controls but did not report less emotional experience. Alternative explanations for the findings are considered as are directions for future research.     

Homicidality in schizophrenia: a replication study

This study attempted to replicate the results of R. C. Schwartz, S. Petersen, and J. L. Skaggs (2001) by testing predictors of homicidality in a new sample of participants with schizophrenia. Results of multiple regression analyses showed that manic symptoms and substance abuse were significantly positively correlated with more extreme homicidality. Global Assessment of Functioning scale ratings were significantly negatively correlated with ratings on homicidality. Finally, men displayed significantly heightened homicidality as compared with women. These findings lend support to the hypothesis that clinicians should pay particular attention to evaluating homicidality in patients who are male, have schizophrenia, who abuse substances, who show acute manic symptoms, and whose global functioning has recently declined.     

Beliefs,knowledge and attitudes towards Parkinson's disease among a Xhosa speaking black population in South Africa: A cross-sectional study

IntroductionMany patients with Parkinson's disease (PD) in sub-Saharan Africa (SSA) are thought to be undiagnosed and untreated, leading to poor health outcomes. Increasing rates of diagnosis and treatment, with consequent improvements in the quality of life of people with PD in SSA requires an understanding of how PD is perceived and conceptualized within communities.MethodsA cross-sectional survey was conducted among a group of Xhosa speaking black South Africans. The survey involved the administration of questionnaires on beliefs, knowledge and attitudes about PD to the public, people with PD (PwPD) and traditional healers (THs).Results18% of the participants could identify PD through its symptoms. Mental illness, other diseases, stress, expressing strong emotions, consumption of certain foods or drinks and witchcraft were identified as possible causes of PD. PwPD and THs had a greater knowledge of PD than the public and greater age was a significant predictor of greater knowledge. The public and THs had a greater degree of concern about a range of symptoms of PD compared to PwPD.ConclusionThere is a striking lack of knowledge about PD amongst black South Africans. Almost half the members of the general public interviewed felt that PwPD should not live amongst their community, and a third considered that witchcraft could be a cause of PD. Finding ways to effectively educate members of a community about PD would make it easier for PwPD to adapt to their condition within their communities.     

Reward processing in schizophrenia: a deficit in the representation of value

Patients with schizophrenia demonstrate deficits in motivation and learning that suggest impairment in different aspects of the reward system. In this article, we present the results of 8 converging experiments that address subjective reward experience, the impact of rewards on decision making, and the role of rewards in guiding both rapid and long-term learning. All experiments compared the performance of stably treated outpatients with schizophrenia and demographically matched healthy volunteers. Results to date suggest (1) that patients have surprisingly normal experiences of positive emotion when presented with evocative stimuli, (2) that patients show reduced correlation, compared with controls, between their own subjective valuation of stimuli and action selection, (3) that decision making in patients appears to be compromised by deficits in the ability to fully represent the value of different choices and response options, and (4) that rapid learning on the basis of trial-to-trial feedback is severely impaired whereas more gradual learning may be surprisingly preserved in many paradigms. The overall pattern of findings suggests compromises in the orbital and dorsal prefrontal structures that play a critical role in the ability to represent the value of outcomes and plans. In contrast, patients often (but not always) approach normal performance levels on the slow learning achieved by the integration of reinforcement signals over many trials, thought to be mediated by the basal ganglia.     

Emotional face processing in post-traumatic stress disorder after reconsolidation impairment using propranolol: A pilot fMRI study

Individuals with post-traumatic stress disorder (PTSD) exhibit exaggerated emotional reactions to threatening stimuli, which may represent deregulated fear-conditioning, associated with long-term adaptations in the sympathetic nervous system. Within a repeated measures design, functional magnetic resonance imaging (fMRI) was employed to investigate neural responses to threat in PTSD participants (N = 7), during the presentation of emotional facial expressions. Scans were separated by 6 weekly reconsolidation impairment treatment sessions, consisting of traumatic memory reactivation under the influence of propranolol. Greater activation before versus after treatment emerged in the thalamus and amygdala during fearful versus neutral face processing. Furthermore, participants showed greater activation after versus before treatment in the right anterior cingulate, during fearful relative to happy face processing. PTSD symptoms significantly improved (d = 1.75), post-treatment. These preliminary results suggest that aberrant emotional responding is modulated by noradrenergic plasticity within the amygdala-prefrontal cortex circuit, a neural substrate for the pharmacological treatment of PTSD.     

Increased serum phospholipase A2 activity in schizophrenia: a replication study

Phospholipase A2 (PLA2) is a key enzyme in the metabolism of phospholipids. Because a disordered phospholipid metabolism has frequently been reported in schizophrenia, we investigated the PLA2 activity in serum from 14 drug-free paranoid schizophrenic patients, 20 healthy controls, and 8 nonschizophrenic psychiatric patients. Schizophrenics showed significantly higher PLA2 activity than healthy controls and nonschizophrenic patients. The increment in schizophrenics was not due to increased concentration of pancreatic secretory PLA2, as concerning pancreatic PLA2 no differences were found among the 3 proband groups. The present findings confirm the results of our previous study and suggest that increased serum PLA2 activity might reflect an increment in the intracellular enzyme activity in schizophrenia. In the brain the activation of intracellular PLA2 results in changes in neuronal activity due to alterations in receptor sensitivity and in neurotransmitter metabolism. The possibility that such PLA2-induced mechanisms are involved in the pathogenesis of schizophrenia should be investigated in further experiments.     

Facial emotion processing in schizophrenia: no evidence for a deficit specific to negative emotions in a differential deficit design

People with schizophrenia perform poorly when recognising facial expressions of emotion, particularly negative emotions such as fear. This finding has been taken as evidence of a "negative emotion specific deficit", putatively associated with a dysfunction in the limbic system, particularly the amygdala. An alternative explanation is that greater difficulty in recognising negative emotions may reflect a priori differences in task difficulty. The present study uses a differential deficit design to test the above argument. Facial emotion recognition accuracy for seven emotion categories was compared across three groups. Eighteen schizophrenia patients and one group of healthy age- and gender-matched controls viewed identical sets of stimuli. A second group of 18 age- and gender-matched controls viewed a degraded version of the same stimuli. The level of stimulus degradation was chosen so as to equate overall level of accuracy to the schizophrenia patients. Both the schizophrenia group and the degraded image control group showed reduced overall recognition accuracy and reduced recognition accuracy for fearful and sad facial stimuli compared with the intact-image control group. There were no differences in recognition accuracy for any emotion category between the schizophrenia group and the degraded image control group. These findings argue against a negative emotion specific deficit in schizophrenia.     

Perceptions of a South African schizophrenia population with regards to community attitudes towards their illness

Background With the worldwide shift towards a more community-based psychiatric service delivery approach, stigma and the issues surrounding it have received much attention. However, very little South African data exist and the aim of our study was therefore to investigate the experience of internalized stigma in a South African schizophrenia population with specific emphasis on abuse as a form of stigmatization. Methods A total of 100 subjects at various stages of schizophrenic illness were subjected to a the Internalized Stigma of Mental Illness scale (ISMI) that was modified to include six items focusing specifically on investigating the experience of stigmatization within the South African context. Results A high overall degree of stigmatization was perceived by most subjects, but not equally so for all ISMI areas. When looking at the modified items, 29% felt media-influence to be negative, this seemed to be specifically true for those with matriculation and higher as well as a home-language other than Afrikaans. Thirty nine percent indicated that they had been victims of physical abuse due to their mental illness, with the data suggesting that especially Xhosa-speaking patients, male subjects and those with more admissions and a longer duration of illness experienced this excessively. Discussion Our study confirmed a high overall degree of perceived stigmatization as well as suggesting some evidence for cultural influences on stigma. It was the first to provide South African data and as such can be regarded as central to our efforts in restructuring psychiatric services and clinical practices in a way that would minimize the effects of stigma and ultimately benefit our clients.     

Emotional object and scene stimuli modulate subsequent face processing: an event-related potential study

To understand the processing of facial expressions in terms of social communication, it is important to clarify how they are influenced by environmental stimuli such as natural scenes or objects. We investigated how and when neural responses to facial expressions were modulated by both a natural scene and an object containing emotional information. A facial expression stimulus (fearful/neutral) was presented after a scene or object stimulus (fearful/neutral), and then event-related potentials were recorded from both the onset of scene and facial expression presentation. As in previous studies, for the presentation of the scenes and objects positive-going waves at around 200-500 ms were observed for unpleasant visual stimuli at the Pz and Cz electrodes when the stimuli were intact; however, such a response was not observed when the stimuli were scrambled. During the subsequent facial expression presentation period, although we could not identify a significant interaction between the contextual information and facial expression in the N170 component, we observed a significant interaction in the P2 component: the P2 amplitude of the fearful cued was significantly larger than that of the neutral cued condition when the face was fearful, and the P2 amplitude of the neutral face was significantly larger than that of the fearful face condition when the preceding stimulus was neutral. These findings show that an adjacent, non-face stimulus containing emotional information influences the subsequent processing of facial expressions up to 260 ms, and even in cases when the two stimulus categories are different.     

Memory deficit and long-term outcome in schizophrenia: A preliminary study

Twenty-two schizophrenic patients who presented memory deficit at admission were followed up over a 30- to 40-year period along with 178 schizophrenic patients without memory deficit. Memory deficit at admission predicted poor outcome in marital, occupational, and psychiatric outcome categories. The symptoms and signs of memory deficit were assessed without knowledge of the patient's status at admission. A significantly higher proportion of the memory deficit group continued to show both symptoms and signs of memory deficit at followup. Thus, the presence of memory deficit in schizophrenics was a highly stable variable across a 30- to 40-year period. Implications of the preliminary results of this study are discussed, and future studies are suggested.     

Global-local visual processing in schizophrenia: evidence for an early visual processing deficit.

BACKGROUND: Abnormalities in early-stage visual processing might contribute to observed higher neurocognitive deficits in schizophrenia, but to date no clear link has been established. Schizophrenia has been associated with deficits in the magnocellular visual pathway, suggesting a relative bias for processing elemental (local) as opposed to configural (global) aspects of a hierarchical stimulus; however, global-local paradigm studies in schizophrenia have yielded mixed results. METHODS: In the current study, global-local and event-related potential (ERP) procedures were concomitantly used to assess temporal and spatial characteristics of hierarchical visual stimulus processing abnormalities. RESULTS: Patients (n = 24) had slower and less accurate responses to global stimuli than a healthy comparison group (n = 29). They exhibited a marked decrement in N150 ERP amplitude, which correlated with speed of response to global stimuli. They also failed to show an augmented P300 response to local stimuli. CONCLUSIONS: Behavioral and physiological data are consistent and support a global visual processing deficit in schizophrenia. This is manifest at a relatively early stage of visual processing and might relate to physiological disturbances in areas V3/V3a of the extrastriate cortex.     

Polydipsia and schizophrenia in a psychiatric hospital: a replication study

A prior study in a US state hospital suggested that schizophrenia, smoking and long hospitalization were associated with polydipsia. This study, in another US hospital, attempts to (1) replicate that schizophrenia and smoking are associated with polydipsia, and (2) rule out that this relationship is partly explained by alcohol and drug use. Both studies have similar methodologies. The second sample included 588 inpatients. Models of variables associated with polydipsia were developed using logistic regression.In the second study, after correcting for other factors, the association between polydipsia and schizophrenia showed a borderline significance, while polydipsia and smoking displayed a significant association. Neither organic brain lesions, nor alcohol or drug use, were associated with polydipsia. An analysis combining both samples showed that: (1) schizophrenia, long hospitalization, smoking and heavy smoking were significantly associated with polydipsia, and (2) male gender and Caucasian race (but not smoking) increased the risk of developing water intoxication in polydipsic patients.These two studies in severely mentally ill patients suggest that the association of polydipsia with schizophrenia, smoking and chronicity is consistent and independent from the definition of polydipsia (by staff, a biological method or the combination of both). Psychiatric medications do not appear to explain most cases of polydipsia in these patients.     

Specific motion processing pathway deficit during eye tracking in schizophrenia: a performance-matched functional magnetic resonance imaging study.

BACKGROUND: The neural mechanisms underlying smooth pursuit eye movement (SPEM) abnormalities in schizophrenia are not well understood. Previous evidence suggests that a deficit in the processing of internal representations of object motion (extraretinal motion) contributes to SPEM deficits in patients. Functional magnetic resonance imaging (fMRI) activation was compared between patients and control subjects to determine whether schizophrenia patients exhibit abnormal cerebral activation in regions associated with extraretinal motion processing during SPEM. METHODS: Patients and control subjects were selected based on matched performance in the closed-loop gain. Despite similar performance on closed-loop pursuit gain, patients showed consistent deficits in extraretinal motion based on predictive pursuit. In the magnet, subjects were tested using a traditional smooth-pursuit task that elicits closed-loop response. RESULTS: Patients had reduced pursuit-related activation in several known extraretinal motion processing areas including frontal and supplemental eye fields, medial superior temporal cortex, and anterior cingulate. Patients also showed increased activation in medial occipitotemporal cortex. CONCLUSIONS: These results provide functional anatomic evidence supporting reduced function in the extraretinal motion processing pathway in schizophrenia. Increased activation in medial occipitotemporal cortex suggests an increased dependence on immediate retinal motion information, which may be used to compensate for reduced extraretinal signaling during sustained visual tracking.     

Early-stage face processing dysfunction in patients with schizophrenia

OBJECTIVE: Deficits in emotional processing are evident in patients with schizophrenia. Since recent studies have indicated dysfunctions in cortical areas involved in face processing, this study investigated the early processing of faces in schizophrenia patients through the use of event-related potentials. METHOD: Event-related potential responses were obtained from 24 schizophrenia patients and 28 healthy comparison subjects who were presented with pictures of faces and pictures of buildings (control stimuli). RESULTS: Schizophrenia patients displayed significantly lower differences in the face-specific N170 component between the face and building pictures than did the healthy comparison subjects. CONCLUSIONS: This finding suggests a dysfunction of early-stage visual processing of faces in patients with schizophrenia.