Correlates of substance misuse in patients with first-episode schizophrenia and schizoaffective disorder

Impact of a family history of mental disorders on the characteristics of patients with early psychosis

AIM

Children of parents with psychiatric illness have a higher risk of developing psychiatric disorders. This is particularly the case for psychoses and the evolution of these disorders could likely differ. The aim of this study was to study the impact of a first-degree and second-degree family history of psychiatric disorders (FHPD) on the characteristics of patients with early psychosis in a specialized programme.

METHOD

This research is a prospective study based on 408 patients aged 18-35 years enrolled in the Treatment and Early Intervention in Psychosis Program (TIPP) with a three-years follow-up. Various characteristics were compared between patients with first-degree-FHPD and those without, then between patients with 2nd degree-FHPD and those without. The influence of the number of parents with first or second degree FHPD on clinical characteristics was also studied.

RESULTS

Our results showed an influence of FHPD on the characteristics of patients presenting a first episode of psychosis. Over the 3 years of follow-up, patients with at least one second-degree relative showed more negative and depressive symptoms and poorer general functioning than patient who did not. The number of parents with first or second degree FHPD was also negatively associated with several clinical variables.

CONCLUSION

The results of this study confirm the existence of a distinct premorbid profile and a different evolution in patients with FHPD, which is not limited to first-degree relatives. This suggests the importance of specific needs that should be addressed during treatment.

The Impact of THC and CBD in Schizophrenia: A Systematic Review

Background: People with schizophrenia are more likely to develop cannabis use disorder (CUD) and experience worse outcomes with use. Yet as cannabis is legalized for medical and recreational use, there is interest in its therapeutic potential. Objectives: To conduct a systematic review summarizing the design and results of controlled trials using defined doses of THC and CBD in schizophrenia. Method: A keyword search of eight online literature databases identified 11 eligible reports. Results: One placebo controlled trial (13 stable patients without CUD) found that intravenous THC increased psychosis and worsened learning/recall. Two reports of a functional magnetic resonance (fMRI) study of smoked or oral THC in 12 abstinent patients with schizophrenia and CUD found no change in symptoms and cognition, and an amelioration of impaired resting state brain function in areas implicated in reward function and the default mode network. One 4 week trial in acutely psychotic inpatients without CUD (mean age 30 y) found 800 mg CBD to be similarly efficacious to amisupride in improving psychosis and cognition. Two 6 week studies of CBD augmentation of antipsychotics in stable outpatients reported mixed results: CBD 600 mg was not more effective than placebo; CBD 1,000 mg reduced symptoms in a sample that did not exclude cannabis use and CUD. A brain fMRI and proton magnetic resonance spectroscopy study of single dose CBD in a sample that did not exclude CUD and cannabis use found that CBD improved symptoms and brain function during a learning/recall task and was associated with increased hippocampal glutamate. Discussion: There is substantial heterogeneity across studies in dose, method of drug delivery, length of treatment, patient age, whether patients with cannabis use/CUD were included or excluded, and whether patients were using antipsychotic medication. Conclusion: There is insufficient evidence for an effect of THC or CBD on symptoms, cognition, and neuroimaging measures of brain function in schizophrenia. At this time, research does not support recommending medical cannabis (THC or CBD) for treating patients with schizophrenia. Further research should examine THC and CBD in schizophrenia with and without comorbid CUD and consider the role of CBD in mitigating symptom exacerbation from THC.

The prevalence and clinical correlates of substance use disorders in patients with psychotic disorders from an Upper-Middle-Income Country

Background

Substance use disorders (SUDs) occur frequently in patients with psychotic disorders and have been associated with various demographic and clinical correlates. There is an absence of research on the prevalence and clinical correlates of SUDs in psychotic disorders in low-and-middle-income countries (LMICs).

Aim

We aimed to determine the prevalence and correlates of SUDs in psychotic disorders.

Setting

Patients attending a large secondary-level psychiatric hospital in Cape Town South Africa.

Methods

We used the Structured Clinical Interview for DSM-IV (SCID-I) to determine psychiatric and substance use diagnoses, depressive, anxiety, obsessive-compulsive and post-traumatic symptoms. We used logistic regression models to determine significant predictors of SUDs.

Results

In total sample (N = 248), 55.6% of participants had any SUD, 34.3% had cannabis use disorders, 30.6% alcohol use disorders, 27.4% methamphetamine use disorders, 10.4% methaqualone use disorders and 4.8% had other SUDs. There were significant associations with male sex for most SUDs, with younger age and Coloured ethnicity for methamphetamine use disorders, and with lower educational attainment for cannabis use disorders. Anxiety symptoms and suicide attempts were significantly associated with alcohol use disorders; a diagnosis of a substance induced psychosis with cannabis and methamphetamine use disorders. Across most SUDs legal problems and criminal involvement were significantly increased.

Conclusion

This study found a high prevalence and wide distribution of SUDs in patients with psychotic disorders, consistent with previous work from high income countries. Given clinical correlates, in individuals with psychotic disorders and SUDs it is important to assess anxiety symptoms, suicidality and criminal involvement.

First-episode psychosis and substance use in Nelson Mandela Bay: Findings from an acute mental health unit

Background

Use of psychoactive substances is a common finding in studies on first-episode psychosis (FEP), and this has prognostic implications. We know very little about psychoactive substance use (SU) among patients with FEP in the Eastern Cape province (EC) of South Africa (SA).

Aim

The study seeks to determine SU prevalence and associated features among inpatients with non-affective FEP in an acute mental health unit (MHU) in Nelson Mandela Bay, EC.

Setting

Researchers conducted a retrospective clinical file review of a 12-month admission cohort of patients with FEP, without a concurrent mood episode, to the Dora Nginza Hospital MHU. Information collected included SU history, psychiatric diagnoses, and demographics. Data were then subjected to statistical analysis.

Methods

Researchers conducted a retrospective clinical file review of a 12-month admission cohort of patients with FEP, without a concurrent mood episode, to the Dora Nginza Hospital MHU. Information collected included SU history, psychiatric diagnoses and demographics. Data were then subjected to statistical analysis.

Results

A total of 117 patients (86 [73.5%] males; 31 [26.5%] females) aged 18–60 years (mean 29 years) met the inclusion criteria. After controlling for missing information, 95 of 117 (81.2%) patients had a history of active or previous SU, 82 of 90 (91.1%) were single and 61 of 92 (66.3%) were unemployed. A significant association was found between SU and unemployment (p < 0.001), as well as male sex (p < 0.001). The most common substances used were cannabis (59.8%), followed by alcohol (57.3%) and stimulants (46.4%).

Conclusion

In keeping with national and international literature, the results of this study showed a high prevalence of substance use in South African patients with first-episode psychosis. The high prevalence of lifetime substance use in this cohort compared to previous studies in South Africa requires further investigation and highlights the urgent need for dual diagnosis services in the Eastern Cape province.

Early Substance Use Cessation Improves Cognition-10 Years Outcome in First-Episode Psychosis Patients

Background: Cognitive impairment may be a risk factor for, as well as a consequence of, psychosis. Non-remitting symptoms, premorbid functioning, level of education, and socioeconomic background are known correlates. A possible confounder of these associations is substance use, which is common among patients with psychosis and linked to worse clinical outcomes. Studies however show mixed results for the effect of substance use on cognitive outcomes. In this study, the long-term associations of substance use with cognition in a representative sample of first-episode psychosis patients were examined. Methods: The sample consisted of 195 patients. They were assessed for symptom levels, function, and neurocognition at 1, 2, 5, and 10 years after first treatment. Test scores were grouped into factor analysis-based indices: motor speed, verbal learning, visuomotor processing, verbal fluency, and executive functioning. A standardized composite score of all tests was also used. Patients were divided into four groups based on substance-use patterns during the first 2 years of treatment: persistent users, episodic users, stop-users, and nonusers. Data were analyzed using linear mixed effects modeling. Results: Gender, premorbid academic functioning, and previous education were the strongest predictors of cognitive trajectories. However, on motor speed and verbal learning indices, patients who stopped using substances within the first 2 years of follow-up improved over time, whereas the other groups did not. For verbal fluency, the longitudinal course was parallel for all four groups, while patients who stopped using substances demonstrated superior performances compared with nonusers. Persistent users demonstrated impaired visuomotor processing speed compared with nonusers. Within the stop- and episodic use groups, patients with narrow schizophrenia diagnoses performed worse compared with patients with other diagnoses on verbal learning and on the overall composite neurocognitive index. Discussion: This study is one of very few long-term studies on cognitive impairments in first-episode psychosis focusing explicitly on substance use. Early cessation of substance use was associated with less cognitive impairment and some improvement over time on some cognitive measures, indicating a milder illness course and superior cognitive reserves to draw from in recovering from psychosis.

Prevalence of comorbid substance use in schizophrenia spectrum disorders in community and clinical settings, 1990-2017: Systematic review and meta-analysis

BACKGROUND

Comorbidity is highly prevalent between substance use disorders (SUDs) and schizophrenia. This systematic review and meta-analysis estimated prevalence rates of SUDs in epidemiological and treatment-seeking patients diagnosed with schizophrenia or first episode psychosis.

METHODS

A literature search of Medline, EMBASE, PsycINFO and CINAHL databases was conducted from 1990 to 2017 inclusive. Prevalence of co-morbid SUDs and schizophrenia were extracted and odds ratios (ORs) were calculated using random effects meta-analysis. Combining like studies was dictated how authors reported substance use.

RESULTS

There were 123 included articles with a total sample size of 165,811 subjects that yielded six epidemiological studies, 11 national or state case-registry studies, 20 large cohort studies and 86 clinical studies using in- or out-patient samples. The prevalence of any SUD was 41.7%, followed by illicit drugs (27.5%), cannabis (26.2%), alcohol (24.3%) and stimulant use (7.3%). Meta-analysis showed the pooled variance of any SUD in males was 48% which was significantly higher than that for females with schizophrenia (22.1%, OR 3.43, 95% CI 3.01, 3.92). Patients with SUD had an earlier age of onset of schizophrenia. Meta-regression showed prevalence increased over time for illicit drugs but not for other substances, including alcohol.

CONCLUSIONS

The meta-analysis revealed that SUDs in schizophrenia is highly prevalent and rates have not changed over time. This indicates SUD are difficult to treat in this patient population and there is an urgent need for more informative studies to help develop better prevention, detection and treatment of SUDs in persons with schizophrenia and co-morbid disorders.

Study to determine the prevalance of substance use and factors associated with it, in first-episode of psychosis

BACKGROUND

Psychoactive substance use occurs commonly in patients with psychotic disorders.

AIM

This study aimed to determine the prevalence of substance use in first-episode psychotic patients and to evaluate the association between substance use and various sociodemographic variables.

MATERIALS AND METHODS

This was a cross-sectional study, and symptomatic first-episode, treatment-naive psychosis patients were included (n = 79). A semi-structured pro forma was used for the evaluation of sociodemographic and clinical characteristics. The patients were then interviewed for use of any psychoactive substance in their lifetime. In each case, the history was corroborated by a family member or a caregiver. Wherever required, a second interview was conducted.

RESULTS

The mean age at the onset of psychotic disorder for substance users was 36.09 years and for nonusers was 35.50 years. Almost three-fourth of the patients reported the use of at least one substance in their lifetime. Alcohol use was reported by 40.50% of patients, tobacco by 55%, and cannabis by 8.86%. It was significant in patients who were diagnosed with schizophrenia, acute and transient psychotic disorder, persistent delusional disorder, and unspecified nonorganic psychotic disorder.

CONCLUSION

The results show a high prevalence of psychoactive substance abuse compared to the prevalence in the general population. This has tremendous significance in the management of such illness, which is known to impact the prognosis adversely.

A comparative study of socio-demographic and substance use correlates in early-onset psychosis

BACKGROUND

Comorbid substance use, particularly cannabis among adolescents with mental illness, is a major public health concern in developing countries with limited mental health resources. Better understanding of the association between cannabis use and other polysubstance use and early mental illness will provide for more targeted early interventions.

AIM

This aim of this study was to examine the socio-demographic profile and cannabis use characteristics among adolescents with first-episode early-onset psychosis (EOP) and compare with age-matched and gender-matched adolescents with first-episode non-psychotic mental illness (controls).

METHOD

Forty-five adolescents with first-episode EOP and 45 controls were assessed using a clinical interview, Positive and Negative Syndrome Scale and World Health Organization Alcohol, Smoking and Substance Involvement Screening test (ASSIST) for substance-related problems.

RESULTS

There were significant socio-demographic differences among the adolescents with EOP (73% Black, 64% from low family income, 44% from rural areas) compared with controls (24% Black, 53% from low family income, 2% from rural areas). Although there was no difference in lifetime cannabis use, EOP adolescents differed in motivation for cannabis use, had increased current cannabis use (38%, P = 0.01) and more frequent use (52%, P = 0.04) compared with controls (16% current and 18% frequent use). EOP adolescents reported more hazardous use with higher ASSIST mean cannabis-specific involvement scores (EOP 10,2; controls 2,3; P = 0.004).

CONCLUSION

The differences in socio-demographic variables may reflect the marked disparity in access to mental health care for rural Black youth. Psychotic youth may be more vulnerable to comorbid cannabis-related problems than other mentally ill adolescents. The study highlights the need for early introduction of substance use interventions among adolescents with mental illness.

Demographic and clinical correlates of substance use disorders in first episode psychosis

BACKGROUND

We assessed the prevalence and correlates of lifetime substance use disorders in people with first episode psychosis using the baseline data from the Recovery After an Initial Schizophrenia Episode (RAISE) Early Treatment Program study.

METHODS

Research staff assessed 404 first episode patients at 34 community mental health centers across the United States with the Structured Clinical Interview for DSM-IV for diagnoses of psychotic and substance use disorders. Logistic regression was used to evaluate the relationships between participant characteristics and lifetime substance use disorders, followed with generalized linear mixed-effects regression models to identify unique predictors of lifetime substance use disorders.

RESULTS

Approximately one-third of participants reported recent alcohol use (36.6%) and cannabis use (30.7%), and one half (51.7%) met criteria for any lifetime alcohol or drug use disorder. Lifetime substance use disorders were associated with male gender, White race, higher excited (hyperactivity, mood lability, impulsivity, hostility, and uncooperativeness), psychotic and depressive symptoms, less impaired cognition, and greater perceived stigma. Gender, race, and excited symptoms were the most consistent unique predictors of lifetime substance use disorders found in multivariate analyses.

CONCLUSIONS

Half of first episode psychosis patients have co-occurring substance use disorders, which are associated with both more severe symptoms and greater perceptions of stigma. Programs aiming to serve these patients must have the skills and clinical strategies to help people with these unique characteristics.

Cannabis use related to early psychotic onset: Role of premorbid function

The present cross-sectional study investigates the relation between Cannabis and the development of a psychotic disorder. The main objective is to explore the relations between Cannabis use and psychosis onset, premorbid adjustment cognitive impairment and familiarity. Forty-three patients with a diagnosis of Psychotic Disorder were recruited and divided in two groups based on Cannabis use before onset: Cannabis-using patients (PCU, N=21) and Cannabis-free patients (PCF, N=22). Cognitive functioning was evaluated by Trail Making Test A and B (TMT), Rey-Osterrieth Complex Figure Test (ROCF), and the Rey Auditory-Verbal Learning Test (RAVLT). Premorbid functioning was assessed retrospectively through the Premorbid Adjustment Scale (PAS). PCU group showed earlier onset of the psychotic disorder compared to PCF (p=0.008). This finding was not influenced by age or positive family history for psychiatric illness. PCU subjects showed a worse premorbid functioning respect to PCF and this difference was found to impact on the early onset in the PCU group. In conclusion the present study suggests the hypothesis of an interactive role of Cannabis and poor premorbid school adjustment in the development of psychotic disorders.

Substance use associated with short sleep duration in patients with schizophrenia or schizoaffective disorder

STUDY OBJECTIVES

To examine the association between substance use and short sleep duration in individuals with schizophrenia or schizoaffective disorder, depressive type (SADD).

DESIGN

Cross-sectional, retrospective study.

SETTING

Urban, suburban, and rural centers across the United States.

PARTICIPANTS

2,462 consented, adult individuals with schizophrenia or schizoaffective disorder, depressive type (SADD). Participants included inpatients in acute or chronic care settings as well as outpatients and residents in community dwellings.

MEASUREMENTS

Substance use was assessed with 10 questions adopted from well-validated measures (e.g., CAGE questionnaire) for alcohol, marijuana, and illicit drugs. Short sleep duration was defined as <6 hr of self-reported sleep per night.

RESULTS

Close to 100% of our sample used nicotine while 83% used substances other than nicotine. More importantly, there was a significant association between substance use and short sleep duration. Interestingly, this association was strongest among African-Americans with schizophrenia or SADD.

CONCLUSIONS

Because psychiatric medications often target chemical receptors involved with both sleep and substance use, understanding the association between short sleep duration and substance use in individuals with schizophrenia and SADD is important. Given that the majority of premature deaths in individuals with psychotic illness are due to medical conditions associated with modifiable risk factors, prospective studies designed to examine the effect of short sleep duration on behaviors like substance use should be undertaken. Finally, analyzing genetic and environmental data in a future study might help illuminate the strong association found between short sleep duration and substance use in African-Americans with schizophrenia and SADD. © 2015 Wiley Periodicals, Inc.

Cannabis use in first episode psychosis: Meta-analysis of prevalence, and the time course of initiation and continued use

OBJECTIVES

Cannabis use is prevalent among people with first episode psychosis and the epidemiology of its use in early psychosis is unclear. We performed a meta-analysis of observational studies to determine; (1) the interval between age at initiation of cannabis use and age at onset of first episode psychosis, (2) the prevalence of cannabis use at time of first episode psychosis, and (3) the odds of continuing cannabis following treatment for first episode psychosis.

DATA SOURCES

Search of electronic databases MEDLINE, EMBASE, PsycINFO, Web of Science and CINAHL for English-language papers using search terms (psychosis OR schizophrenia) AND (cannabis OR marijuana) IN (title OR keyword OR abstract), current to October 2014.

STUDY SELECTION

Studies were included if they reported on prevalence of current cannabis use in first episode psychosis cohorts. A total of 37 samples were included for meta-analysis.

DATA EXTRACTION

Rates of cannabis use in each sample were extracted to determine prevalence estimates. The age at initiation of regular cannabis and age at onset of psychosis were used to determine the length of cannabis use preceding psychosis. Prevalence estimates at first episode psychosis and various time points of follow-up following first episode psychosis were analysed to determine odds ratio of continuing cannabis use. Data synthesis was performed using random-effects meta-analyses.

RESULTS

The pooled estimate for the interval between initiation of regular cannabis use and age at onset of psychosis was 6.3 years (10 samples, standardised mean difference = 1.56, 95% confidence interval = [1.40, 1.72]). The estimated prevalence of cannabis use at first episode psychosis was 33.7% (35 samples, 95% confidence interval = [31%, 39%]). Odds of continued cannabis use between 6 months and 10 years following first episode psychosis was 0.56 (19 samples, 95% confidence interval = [0.40, 0.79]).

The prevalence and correlates of childhood trauma in patients with early psychosis

OBJECTIVE

To describe the prevalence and demographic, clinical and functional correlates of childhood trauma in patients attending early psychosis clinics.

METHOD

Participants were recruited from outpatients attending four early psychosis services. Exposure to childhood trauma was assessed using the Childhood Trauma Questionnaire (CTQ). Psychopathology was measured using the Positive and Negative Syndrome Scale and the Depression, Anxiety and Stress Scale. Social and vocational functioning and substance use were also assessed.

RESULTS

Over three-quarters of the 100 patients reported exposure to any childhood trauma. Emotional, physical and sexual abuse were reported by 54%, 23% and 28% of patients, respectively, while 49% and 42% of patients reported emotional and physical neglect, respectively. Female participants were significantly more likely to be exposed to emotional and sexual abuse. Exposure to childhood trauma was correlated with positive psychotic symptoms and higher levels of depressive, anxiety and stress symptoms; however, it had no impact on social or vocational functioning or recent substance use.

CONCLUSION

Exposure to childhood trauma was common in patients with early psychosis, and associated with increased symptomatology. Existing recommendations that standard clinical assessment of patients with early psychosis should include inquiry into exposure to childhood trauma are supported.

Revisiting the 'self-medication' hypothesis in light of the new data linking low striatal dopamine to comorbid addictive behavior

Persons with schizophrenia are at a high risk, almost 4.6 times more likely, of having drug abuse problems than persons without psychiatric illness. Among the influential proposals to explain such a high comorbidity rate, the 'self-medication hypothesis' proposed that persons with schizophrenia take to drugs in an effort to cope with the illness and medication side effects. In support of the self-medication hypothesis, data from our earlier clinical study confirmed the strong association between neuroleptic dysphoria and negative subjective responses and comorbid drug abuse. Though dopamine has been consistently suspected as one of the major culprits for the development of neuroleptic dysphoria, it is only recently our neuroimaging studies correlated the emergence of neuroleptic dysphoria to the low level of striatal dopamine functioning. Similarly, more evidence has recently emerged linking low striatal dopamine with the development of vulnerability for drug addictive states in schizophrenia. The convergence of evidence from both the dysphoria and comorbidity research, implicating the role of low striatal dopamine in both conditions, has led us to propose that the person with schizophrenia who develops dysphoria and comorbid addictive disorder is likely to be one and the same.

A comparison of treatment adherence in individuals with a first episode of psychosis and inpatients with psychosis

In predicting treatment compliance in individuals with severe mental illness, research has focused on variables such as substance abuse, personality, history of child abuse, and symptomatology, although these relationships have not been investigated in great detail in individuals at the onset of mental illness. To better understand these correlates of treatment compliance, two samples were examined: a sample of 117 individuals presenting with a first episode of psychosis and a more chronic forensic sample of 65 participants recruited from a psychiatric hospital. These samples were investigated for service engagement in terms of violence history, substance abuse, symptom severity, psychopathic traits and history of childhood abuse. Linear regressions performed for the first episode sample revealed that childhood physical abuse was the strongest predictor of poor service engagement, followed by problems with alcohol, a history of physical violence, any history of violence and higher psychopathic traits. Linear regression revealed for the forensic group that a lower level of service engagement was most strongly predicted by a history of childhood abuse and a higher score on the Brief Psychiatric Rating Scale (BPRS). Results are presented in light of the existing literature and clinical implications are discussed.

A clinical comparison of schizophrenia with and without pre-onset cannabis use disorder: a retrospective cohort study using categorical and dimensional approaches

BACKGROUND

A high prevalence of cannabis use disorder has been reported in subjects suffering from schizophrenia, fuelling intense debate about whether schizophrenia with pre-onset cannabis use disorder may be a distinct entity with specific features or whether cannabis use disorder can precipitate schizophrenia in genetically vulnerable subjects.

METHODS

We retrospectively assessed schizophrenia subjects with and without pre-onset cannabis use disorder on the basis of their clinical features, assessed categorically and dimensionally with the operational criteria checklist for psychotic illnesses (OCCPI). We also investigated whether the two groups could be differentiated on the basis of a history of psychiatric disorders in first-degree relatives. A principal component factor analysis of the OCCPI items was used to identify specific symptom dimensions. The relationships between symptom dimensions and cannabis status were analysed by point-biserial correlation analysis to control for sex and age at time of the assessment and illness duration.

RESULTS

One hundred and seventy-one subjects with a diagnosis of schizophrenia were included. Among them, forty-one patients (18.2 % of the sample) had a cannabis use disorder before or at the time of the onset of schizophrenia. We found similar results in symptoms patterns or family history between patients with and without pre-onset cannabis use disorder.

CONCLUSIONS

Our results clearly argue against cannabis-associated schizophrenia being a relevant distinct clinical entity of schizophrenia with specific features.

Substance Use in Patients With First-Episode Psychosis: Is Gender Relevant?

OBJECTIVE

Only a few studies in patients with first-episode psychosis have included gender in the study hypothesis or considered this a primary study variable. The aim of this study was to explore the influence of gender in the pattern of substance use in patients with first-episode psychosis.

METHODS

This is a sub-analysis of a randomized open clinical trial that compared 1-year treatment retention rates of patients with first-episode psychosis randomized to haloperidol, olanzapine, quetiapine, risperidone, or ziprasidone. Our sub-analysis included 85 men and 29 women.

RESULTS

Substance use was relatively high among these patients and differed significantly by gender. Men were more likely to use substances overall than women (89.4% for men vs. 55.2% for women), χ(2) = 16.2, df = 1, p <.001, and were also more likely to use alcohol (χ(2) = 13, df = 1, p <.001), cannabis (χ(2) = 9.9; df = 1, p <.002), and cocaine (χ(2) = 10.3; df = 1, p <.001), compared to women. While there were no gender differences in age at first consumption of alcohol or cocaine, men were significantly younger at first consumption of cannabis (M = 16.08 years, SD = 2.1) than women (M = 18.0 years, SD = 3.8), F(1, 59) = 5, p <.02. When analyzed separately by gender, women showed no significant differences in the influence of number of substances used on age at onset of psychosis, F(3, 29) = 1.2, p =.30. However, there was a significant difference among men, with earlier onset of psychosis noted in men consuming multiple substances; F(4, 85) = 5.8, p <.0001. Regarding prediction of age at onset of psychosis, both male gender and the use of a higher number of substances significantly predicted an earlier age at onset of psychosis.

CONCLUSIONS

Our study provides some evidence of gender differences in the pattern of substance use in patients with first-episode psychosis, suggesting the possible need for gender-specific approaches in the interventions performed in these patients. This study is registered as #12610000954022 with the Australian New Zealand Clinical Trials Registry (www.anzctr.org.au).

The Cannabis Pathway to Non-Affective Psychosis may Reflect Less Neurobiological Vulnerability

There is a high prevalence of cannabis use reported in non-affective psychosis. Early prospective longitudinal studies conclude that cannabis use is a risk factor for psychosis, and neurochemical studies on cannabis have suggested potential mechanisms for this effect. Recent advances in the field of neuroscience and genetics may have important implications for our understanding of this relationship. Importantly, we need to better understand the vulnerability × cannabis interaction to shed light on the mediators of cannabis as a risk factor for psychosis. Thus, the present study reviews recent literature on several variables relevant for understanding the relationship between cannabis and psychosis, including age of onset, cognition, brain functioning, family history, genetics, and neurological soft signs (NSS) in non-affective psychosis. Compared with non-using non-affective psychosis, the present review shows that there seem to be fewer stable cognitive deficits in patients with cannabis use and psychosis, in addition to fewer NSS and possibly more normalized brain functioning, indicating less neurobiological vulnerability for psychosis. There are, however, some familiar and genetic vulnerabilities present in the cannabis psychosis group, which may influence the cannabis pathway to psychosis by increasing sensitivity to cannabis. Furthermore, an earlier age of onset suggests a different pathway to psychosis in the cannabis-using patients. Two alternative vulnerability models are presented to integrate these seemingly paradoxical findings.

Predictors of substance use reduction in an epidemiological first-episode psychosis cohort

AIM

To assess the predictors of a significant decrease or cessation of substance use (SU) in a treated epidemiological cohort of first-episode psychosis (FEP) patients.

METHOD

Participants were FEP patients of the Early Psychosis Prevention and Intervention Centre in Australia. Patients' medical files were reviewed using a standardized file audit. Data on 432 patients with FEP and baseline co-morbid substance use disorder (SUD) were available for analysis. Predictors of reduction/cessation of SU at follow up were examined using logistic regression analyses.

RESULTS

In univariate analyses, a reduction/cessation of SU was predicted by baseline measures reflecting higher education, employment, accommodation with others, cannabis use disorder (CUD) only (rather than poly-SUDs), better global functioning and better premorbid social and occupational functioning, later age at onset of psychosis, and a diagnosis of non-affective psychosis. In multivariate analysis, CUD alone and better premorbid social and occupational functioning remained significant predictors.

CONCLUSIONS

Addressing SUDs and social and occupational goals in people with FEP may offer opportunities to prevent SUDs becoming more severe or entrenched. Further longitudinal research on recovery from SU and FEP is needed to disentangle directions of influence and identify key targets for intervention.

Impact of substance use on conversion to psychosis in youth at clinical high risk of psychosis

Elevated rates of substance use (alcohol, tobacco, cannabis) have been reported in people at clinical high risk (CHR) of developing psychosis and there is some evidence that substance use may be higher in those who convert to a psychosis compared to non-converters. However little is known about the predictive value of substance use on risk of conversion to psychosis in those at CHR of psychosis. In the current study, 170 people at CHR of psychosis were assessed at baseline on severity of alcohol, tobacco and cannabis using the Alcohol and Drug Use Scale. Participants were recruited across three sites over a four year period as part of the Enhancing the Prospective Prediction of Psychosis (PREDICT) study. Predictors of conversion to psychosis were examined using Cox proportional hazards models. Results revealed that low use of alcohol, but neither cannabis use nor tobacco use at baseline, contributed to the prediction of psychosis in the CHR sample. Prediction algorithms incorporating combinations of additional baseline variables known to be associated with psychotic conversion may result in increased predictive power compared with substance use alone.

Substance use in clinical high risk for psychosis: a review of the literature

AIM

In the literature, there is evidence suggesting an association between substance use and psychosis. However, little is known about substance use in those who may be in the pre-psychotic phase, that is, those who are putatively prodromal are considered to be at clinical high risk (CHR) of developing psychosis.

METHODS

We conducted a review of publications measuring patterns and rates of substance use in CHR for psychosis individuals and the effects on the transition to psychosis.

RESULTS

Of 5527 potentially relevant research papers, 10 met inclusion criteria of CHR subjects and specifically mentioned substance use in the sample. The results of these studies varied. Cannabis, alcohol and tobacco/nicotine were reported as the most commonly used substances. There was limited information on the changes in patterns of use over time. Two out of the ten studies found a significant association between the use of substances and subsequent transition to psychosis. In one of these studies, substance abuse was a predictor of psychosis when included as a variable in a prediction algorithm. In the other study, the abuse of cannabis and nicotine was associated with transition to psychosis.

CONCLUSIONS

We found limited evidence to suggest that increased rates of substance use may be associated with transition to psychosis. However, further prospective research examining the association between substance use and transition to psychosis is required before any firm conclusions can be made.

Impact of substance use disorder on presentation and short-term course of schizophrenia

The aim of the present study was to compare a cohort of schizophrenia patients with substance use disorder (SUD) with a similar cohort of schizophrenia patients without SUD with regard to sociodemographic variables, clinical variables, psychopathology, anxiety symptoms, depressive symptoms, treatment outcome, and side effect profile of drugs. A total of 143 consecutive inpatients with ICD-10 DCR diagnosis of schizophrenia were included after obtaining informed consent. Patients were evaluated by a semistructured data sheet and Maudsley Addiction Profile. They were then rated by Positive and Negative Symptoms Scale, Calgary Depression Scale, Hamilton Anxiety Rating Scale, and Brief Psychiatric Rating Scale at presentation, three weeks, and six weeks. At three weeks and six weeks, they were also evaluated by UKU Side Effect Rating Scale. Substance abuse was detected in 63.6% schizophrenia patients. Nicotine was the commonest substance followed by cannabis and alcohol. Substance users had longer untreated illness and more depressive symptoms at presentation and six-week follow-up. Dual diagnosis patients had difficulty in abstraction at three and six weeks but not at presentation. Schizophrenia patients with SUD had more depressive symptoms. SUD appeared to mask abstraction difficulties at presentation. Schizophrenia patients with SUD should be carefully assessed for presence of depression.

One year follow-up of alcohol and illicit substance use in first-episode psychosis: does gender matter?

Longitudinal studies on first-episode psychosis (FEP) patients have shown a decrease of substance use disorders (SUDs) over the first years of illness, but there has been less focus on the gender aspect. The present study examines stability of alcohol and illicit substance use, with specific focus on gender, in a one year follow-up investigation of 154 FEP patients (91 men, 63 women) in Oslo, Norway, using criteria for DSM-IV substance use disorder diagnosis, the Alcohol Use Disorders Identification Test (AUDIT) and the Drug Use Disorders Identification Test (DUDIT). The results show that cannabis was the most frequently used illicit substance at both times. Significantly more men (34%) than women (13%) had a current illicit SUD at baseline. At follow-up, the rate of illicit SUDs was significantly reduced in men (18%) but not in women (11%). There were no significant gender differences in the rate of current alcohol use disorders (AUD) (men 14%; women 8%) at baseline, and no significant reduction in AUD in any of the genders at follow-up. At follow-up, total AUDIT and DUDIT scores were reduced in men only. In conclusion, the high and persistent rate of SUDs, particularly of cannabis, among men and women during the first year of treatment for psychosis should be addressed in the clinical management of the patients. Female FEP patients who are also substance users may be particularly vulnerable in this regard and warrant closer attention.

Comorbid substance use disorder in schizophrenia: a selective overview of neurobiological and cognitive underpinnings

Although individuals with schizophrenia show a lifetime prevalence of 50% for suffering from a comorbid substance use disorder, substance abuse usually represents an exclusion criterion for studies on schizophrenia. This implies that surprisingly little is known about a large group of patients who are particularly difficult to treat. The aim of the present work is to provide a brief and non-exhaustive overview of the current knowledgebase about neurobiological and cognitive underpinnings for dual diagnosis schizophrenia patients. Studies published within the last 20 years were considered using computerized search engines. The focus was on nicotine, caffeine, alcohol, cannabis and cocaine being among the most common substances of abuse. All drugs of abuse target dopaminergic, glutamatergic and GABAergic transmission which are also involved in the pathophysiology of schizophrenia. Current literature suggests that neurocognitive function might beless disrupted in substance-abusing compared to non-abusing schizophrenia patients, but in particular the neuroimaging database on this topic is sparse. Detrimental effects on brain structure and function were shown for patients for whom alcohol is the main substance of abuse. It is as yet unclear whether this finding might be an artifact of age differences of patient subgroups with different substance abuse patterns. More research is warranted on the specific neurocognitive underpinnings of schizophrenia patients abusing distinct psychoactive substances. Treatment programs might either benefit from preserved cognitive function as a resource or specifically target cognitive impairment in different subgroups of addicted schizophrenia patients.

Differences in associations between cannabis and stimulant disorders in first admission psychosis

BACKGROUND

Substance use in early psychosis is associated with male gender and earlier onset. Evidence about other correlates of substance use is less consistent. Stimulants (e.g. methamphetamine, cocaine) may precipitate psychosis. However the associations of stimulant disorders in early psychosis are difficult to examine because of lower prevalence and overlap with cannabis disorders.

METHODS

Hospital records were used to identify 9919 persons aged 15-29 with a first hospital admission with psychosis in New South Wales (NSW), Australia. Correlates of illicit drug disorders, cannabis disorders and stimulant disorders were examined using univariate and multivariate logistic regression.

RESULTS

Half of first psychosis admissions had comorbid substance diagnoses. Cannabis and stimulant disorders were increased more than ten-fold compared to the age-matched Australian population. Stimulant disorders were equally common in women and men and associated with urban location, social advantage and older age at first admission. Cannabis disorders were associated with male gender, younger age and non-metropolitan location. Diagnoses of drug-induced psychoses were more strongly associated with stimulants than with cannabis. Compared to people with cannabis diagnoses alone, those with both cannabis and stimulant disorders were older, more likely to have a diagnosis of drug-induced psychosis and more likely to have comorbid alcohol disorders.

CONCLUSIONS

Cannabis is the most commonly used substance in psychosis, and the associations of illicit drug use in psychoses are largely those of cannabis disorders. There are significant differences between the personal, socio-economic and diagnostic correlates of cannabis and stimulant disorders in young people with first admission psychosis.

Does accumulating exposure to illicit drugs bring forward the age at onset in schizophrenia?

OBJECTIVE

Whilst cannabis has been associated with an earlier age at onset in schizophrenia, the impact of amphetamine and/or cocaine plus cannabis consumption on age at onset remains unclear. The present study was designed to test the hypothesis that consumption of amphetamine and/or cocaine in addition to cannabis would lead to an earlier age at onset of schizophrenia than that seen for cannabis consumption alone. A secondary objective was to determine what kind of effect additional substance use exerted (e.g. additive, multiplicative).

METHOD

Patients with a diagnosis of schizophrenia were recruited from consecutive admissions to the inpatient and outpatient services of a large psychiatric hospital in Perth, Australia and 167 participants were assessed using the Diagnostic Interview for Psychosis, which included detailed inquiry into illicit drug use in the 12 months prior to the onset of psychiatric symptoms. Participants were categorized into four groups: no illicit substance use (n = 65), cannabis use (n = 68), cannabis plus amphetamine use (n = 25), and cocaine plus cannabis/cocaine plus cannabis plus amphetamine use (n = 9). Analysis of variance was performed to detect trends, and linear regression used to analyze the consumption of each additional substance as a predictor of age at onset.

RESULTS

We observed a linear trend for mean age at onset: 23.34 (SD = 6.91) years for no illicit substance use, 22.51 (SD = 5.27) years for cannabis use, 20.84 (SD = 3.48) years for cannabis plus amphetamine use, and 19.56 (SD = 3.54) years for cocaine plus cannabis/cocaine plus cannabis plus amphetamine use; the variation in the means between groups was statistically significant: F(1,163) = 5.66, p = 0.008, Cohen's d = 0.38. For the consumption of each additional substance, age at onset was earlier by 1.2 years: R (2) = 0.034, F(1,165) = 5.72, p = 0.018.

CONCLUSIONS

Whilst preliminary, these findings suggest that additional consumption of each substance predicted an earlier age at onset by approximately 1 additional year.

Executive functioning in individuals with schizophrenia and/or cocaine dependence

OBJECTIVE

Although little is known about neurocognition in Dual Diagnosis, it has been suggested that Schizophrenia (SZ) patients with comorbid substance use belong to a subgroup with lower genetic vulnerability to develop SZ and, consequently, they show better executive and social premorbid functioning. The first aim of this study was to assess the executive functioning, and the second one was to explore the effect of age of onset of substance use in neurocognition in SZ patients with cocaine dependence.

METHODS

The total sample consisted of 95 male patients, aged 20 to 60 years, divided in three groups: one group with SZ and cocaine dependence (SZ+; n = 30), another group with SZ without cocaine dependence (SZ-; n = 30), and a control group with cocaine dependence without psychiatric comorbidity (COC; n = 35).

RESULTS

We found a better executive functioning in both SZ+ and COC than SZ-. We observed a worse performance of SZ+ patients compared with COC in cognitive set-shifting regardless the age of onset of consumption.

CONCLUSIONS

The results agree with the hypothesis of a lower genetic vulnerability in SZ+ patients to develop psychosis compared with SZ-, who develop it without any additional trigger. However, future research is needed to clarify the current knowledge gaps.

Susceptibility of the adolescent brain to cannabinoids: long-term hippocampal effects and relevance to schizophrenia

Clinical studies report associations between cannabis use during adolescence and later onset of schizophrenia. We examined the causal relationship between developmental cannabinoid administration and long-term behavioral and molecular alterations in mice. Mice were administered either WIN 55,212-2 (WIN), a cannabinoid receptor 1 (CB1) agonist or vehicle (Veh) during adolescence (postnatal day 30-35) or early adulthood (postnatal day 63-70). Behavioral testing was conducted after postnatal day 120 followed by biochemical assays. Adolescent cannabinoid treatment (ACU) leads to deficits in prepulse inhibition and fear conditioning in adulthood. Metabotropic glutamate receptors type 5 (mGluR5), a receptor critically involved in fear conditioning and endocannabinoid (eCB) signaling, is significantly reduced in the ACU mouse hippocampus. Next, we examined expression profiles of genes involved in eCB synthesis (diacylglycerol lipase (DGL)) and uptake (monoacylglycerol lipase (MGL) and fatty acid amide hydrolase (FAAH)) in the experimental mice. We find evidence of increased MGL and FAAH in ACU mice, reflecting increases in eCB uptake and degradation. These data suggest that administration of cannabinoids during adolescence leads to a behavioral phenotype associated with a rodent model of schizophrenia, as indexed by alterations in sensorimotor gating and hippocampal-dependent learning and memory deficits. Further, these deficits are associated with a reduction in hippocampal mGluR5 and a sustained change in eCB turnover, suggesting reduced eCB signaling in the ACU hippocampus. These data suggest that significant cannabis use during adolescence may be a contributory causal factor in the development of certain features of schizophrenia and may offer mGluR5 as a potential therapeutic target.

Is it time to consider comorbid substance abuse as a new indication for antipsychotic drug development?

Comorbid drug abuse in schizophrenia has been consistently reported as high, with estimates ranging between 10-70%. Comorbid addictive states in schizophrenia are possibly multifactorial, yet recent research assigns a significant neurobiological role in its genesis. Abnormalities in hippocampal/cortical function in schizophrenia which mediate reward and reinforcement behavior are identified as central to the development and maintenance of comorbid addictive states. Preliminary data suggest that the vulnerability of patients with schizophrenia to substance use disorders may be a primary disease symptom. The management of comorbid substance abuse in schizophrenia relies on the use of antipsychotic medications. Recent data raise the concern about whether first-generation antipsychotics in long-term use can conversely lead to enhancement of the abused substance's reinforcing properties. Some recent reports have assigned a favorable outcome to clozapine and second-generation antipsychotics, pointing to a possible differential role for various antipsychotics. In view of the high prevalence of comorbid drug abuse in schizophrenia, its impact on outcome of treatment and the recent emerging neurobiological information, it is my contention that comorbid drug abuse constitutes a dimension by itself and deserves to receive an indication in the development of new antipsychotics similar to negative symptoms or cognitive deficits.

The differential effect of illicit drug use on cognitive function in first-episode psychosis and healthy controls

OBJECTIVE

Illicit drug use can result in impairment in cognitive function in healthy individuals. Individuals with a psychotic disorder also show a deficit in cognitive function. Drug use may simply contribute to the characteristic cognitive deficit found in psychosis or alternatively result in a 'double deficit'. This study aims to investigate the association between drug use and cognitive function at the first-episode of psychosis and in community-matched controls.

METHOD

One hundred and seventy-seven patients at the first episode of psychosis completed a battery of neuropsychological tests. Those that had used drugs in the previous year (n = 80) were compared with those who had not used drugs in the previous year (n = 97). A subsample of the first-episode psychosis patients were compared with community-matched controls (n = 110) according to drug-use status.

RESULTS

Patients with a first episode of psychosis who had used drugs performed equally to those who had not used drugs on neuropsychological tests. In contrast, healthy controls who had used drugs in the previous year performed worse on tests of executive function and working memory compared with those controls that had not used drugs.

CONCLUSION

There are differential associations of illicit drug misuse with cognitive function for first-episode psychosis patients and healthy controls.

Relationship between measures of inhibitory processes in patients with schizophrenia: role of substance abuse disorders

Disruption of prepulse inhibition of the startle response (PPI) has been widely identified in patients with schizophrenia, as well as impairment in many domains of cognitive functioning. However, there is some controversy regarding the relationship between PPI and the different neuropsychological tasks assessing inhibition. This controversy may be due to the influence of other variables, such as substance abuse. We aimed to determine whether differences in inhibition in schizophrenia subjects were related to their pattern of substance use and whether there was a correlation between the changes in each process. PPI and neuropsychological functioning were studied in three groups of subjects with schizophrenia (N=73): tobacco dependents (ToD; n=22), multiple substance abusers (MSUD; n=31) and non-substance abusers (non-SUD; n=20). All subjects were assessed using PPI and neuropsychological tests (Stroop and Wisconsin Card Sorting Test [WCST]). ToD showed better pre-attentive inhibitory function compared to the other two groups, and MSUD showed lower resistance to interference. Furthermore, significant correlations were found between PPI, Stroop, and WCST. Our data suggest that there is a relationship between the different tasks assessing inhibition in schizophrenia, being affected by substance abuse history. We also found differences in inhibition capacity depending on substance abuse in patients with schizophrenia.

Perceived reasons for and consequences of substance abuse among patients with psychosis

BACKGROUND

Substance use is a common comorbidity with psychotic illnesses. Although several theories exist to explain this link, individual reasons for use may differ. The aim of this study was to evaluate patient perceptions of the reasons for and consequences of their substance use in patients with psychosis and compare them with those of an age-, sex-, and tobacco use-matched control sample without psychosis.

METHOD

Consecutively admitted patients were divided into 2 groups, those who had substance dependence without psychosis (n = 32), admitted in our addiction unit, and those who had psychotic illness with substance dependence, admitted in our inpatient psychosis unit and referred to as the dual-diagnosis group (n = 62). Patients were administered the Schedules for Clinical Assessment in Neuropsychiatry for ICD-10 Diagnostic Criteria for Research to confirm schizophrenia, bipolar affective disorder, and substance dependence diagnoses and were asked open-ended questions to evaluate the perceived reasons for and consequences of their substance use. The study was conducted from July to September 2006.

RESULTS

There were significant differences between the 2 groups in reasons for maintenance and relapse of both cannabis use and alcohol use, the 2 most common substances. While the substance dependence without psychosis group attributed both maintenance and relapse to external factors such as nature of work, social milieu, or peer pressure, the dual-diagnosis group attributed them to internal factors such as enhancement of positive mood and alleviation of withdrawal effects.

CONCLUSIONS

Individuals with psychosis have greater vulnerability to internal factors, which may maintain substance use. Targeting perceived internal factors may play a useful role in management and possibly identification and prevention of psychosis in vulnerable individuals in the future.

Olanzapine vs. risperidone in patients with first-episode schizophrenia and a lifetime history of cannabis use disorders: 16-week clinical and substance use outcomes

The purpose of this study is to compare the efficacy of olanzapine and risperidone for the acute treatment of first-episode schizophrenia patients with cannabis use disorders. This secondary analysis of a previously published study included 49 first-episode patients with a diagnosis of schizophrenia, schizophreniform disorder, or schizoaffective disorder and a co-occurring lifetime diagnosis of cannabis use disorders randomly assigned to treatment with either olanzapine (n=28) or risperidone (n=21) for 16weeks. The olanzapine group did not differ significantly from the risperidone group for initial response rates of positive symptoms, and rates of cannabis use or alcohol use during the study. Positive symptoms and the Scale for Assessment of Negative Symptoms (SANS) global asociality-anhedonia scores improved over time but did not differ between study medications. In both groups, cannabis use during the study was higher in patients who used cannabis within three months of the admission. Thus, our results suggest that olanzapine and risperidone had a similar initial efficacy on psychotic symptoms and substance use in first-episode patients with co-occurring cannabis use disorders. If clinicians are choosing between olanzapine versus risperidone treatment for this population, their decision should be based upon factors other than symptom response and short-term substance misuse.

Effects of cannabis use on age at onset in schizophrenia and bipolar disorder

BACKGROUND

Cannabis use may decrease age at onset in both schizophrenia and bipolar disorder, given the evidence for substantial phenotypic and genetic overlap between both disorders.

METHODS

766 patients, aged 16 to 65 years, were assessed with the Composite International Diagnostic Interview (CIDI) for substance abuse/use. 676 subjects were diagnosed with schizophrenia and 90 subjects with bipolar disorder. The influence of cannabis use on age at onset in both schizophrenia and bipolar disorder was examined using regression analysis.

RESULTS

Cannabis and other substance use was more frequent in patients with schizophrenia compared to the bipolar group. Both cannabis use and a schizophrenia diagnosis predicted earlier age at onset. There was a significant interaction between cannabis use and diagnosis, cannabis having a greater effect in bipolar patients. Age at onset in users of cannabis was comparable in both diagnostic groups whereas bipolar non-users were significantly older than schizophrenia non-users at onset.

CONCLUSION

Cannabis use may decrease age at onset in both schizophrenia and bipolar patients and reduce the effect of diagnosis. This is consistent with the view that cannabis use may unmask a pre-existing genetic liability that is partly shared between patients with schizophrenia and bipolar disorder.

Pre-illness cannabis use and the early course of nonaffective psychotic disorders: associations with premorbid functioning, the prodrome, and mode of onset of psychosis

INTRODUCTION

Limited research indicates that pre-illness cannabis use may result in an earlier age at onset of psychosis, though little is known about the influence of prior cannabis use on the premorbid and prodromal phases. This study examined the effects of prior or concurrent cannabis (as well as nicotine and alcohol) use on: (1) early adolescent (12-15 years) premorbid functioning, (2) late adolescent (16-18 years) premorbid functioning, (3) two features of the prodrome, and (4) mode of onset of psychosis.

METHODS

Participants included 109 well-characterized first-episode patients hospitalized in public-sector settings. Assessments included ages at initiation of first, weekly, and daily use of substances, the Premorbid Adjustment Scale, the Symptom Onset in Schizophrenia inventory, and a consensus-based best estimate of mode of onset.

RESULTS

Participants having used cannabis at ≤15 years had better early adolescence social functioning than those who had not used cannabis (p=0.02). Conversely, those who had used cannabis at ≤18 years had poorer late adolescence academic functioning (p<0.001). Participants having used cannabis before onset of psychotic symptoms did not differ from those who had not in terms of having had an identifiable prodrome or the number of prodromal symptoms experienced. Whereas 42% of those having used cannabis daily had an acute mode of onset of psychosis, only 20% of those without prior daily cannabis use had an acute onset (p=0.04).

CONCLUSIONS

Findings suggest that cannabis use is associated with premorbid social and academic functioning and mode of onset. Further research is warranted to elucidate the complex associations between cannabis use and diverse early-course features.

Prevalence of Substance Use in People With First-Episode Psychosis

OBJECTIVE

People experiencing a first episode of psychosis often have co-occurring substance use, which increases risk of prolonged psychosis and impairs recovery. This article examines the prevalence of substance use in people with first-episode psychosis.

METHODS

The authors searched MEDLINE and other databases for articles published between 1990 and 2009 that described current or lifetime prevalence of substance use, misuse, abuse, or dependence in individuals with first-episode psychosis.

RESULTS

Forty-four unique studies provided information. More than 25% of individuals with first-episode psychosis in reviewed studies indicated current or lifetime alcohol use, lifetime alcohol abuse/dependence, current or lifetime cannabis use, or lifetime cannabis abuse or dependence. For all substances, lifetime prevalence of abuse/dependence was higher than current abuse/dependence.

CONCLUSIONS

Despite variation in assessment methods, findings were generally consistent. Individuals with first-episode psychosis have lower current substance prevalence than lifetime prevalence, suggesting cessation of some substance use prior to seeking treatment for psychosis.

Substance use in adolescence and psychosis: clarifying the relationship

Adolescence is a time of exploration of the self, and this exploration may involve the use of alcohol and drugs. Sadly, for some, adolescence also marks the first signs of a psychosis. The temporal proximity between the onset of substance use and of psychosis has been the cause of much debate. Here we review the association of alcohol, cannabis, stimulants, and other drugs with psychosis, and we conclude that the use of cannabis and the amphetamines significantly contributes to the risk of psychosis.

How is substance use linked to psychosis? A study of the course and patterns of substance dependence in psychosis

Substance use in mentally ill patients is now a major problem that influences the course and outcome of psychosis. With prevalence ranging up to 60%, several theories were postulated to explain the link. It would be interesting to know if substances have different effects in persons with psychosis than in those without. This study aimed to explore patterns of symptomatology of dependence and comorbid psychiatric illness by comparing and contrasting it with a group suffering from pure substance dependence. Consecutively admitted patients who were matched for age, sex, and tobacco use were divided into 3 groups. These were substance dependence without any comorbid psychiatric disorder (SD; n = 32), schizophrenia with substance dependence (SC; n = 31), and bipolar disorder with substance dependence (BD; n = 31). Patients were administered the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and Mini International Neuropsychiatric Inventory (MINI) to evaluate the chronology of criterion of International Classification of Diseases (ICD)-10 dependence. Results showed that cannabis was the most common substance used by both the SC (100%) and BD (80%) groups. This was followed by alcohol as the most common substance used, with prevalence of 87% in SC and 77% in BD groups. There was a significant difference in the pattern of use of cannabis in patients with psychosis, who developed tolerance much faster (P = .018) and had longer durations of cannabis use (P = .001) than the SD group. The presence of "loss of control" over drug use criterion seems to be a specific marker predicting development of dependence and psychosis. Cannabis use is more strongly associated with development of psychosis than any other substance.

Are cannabis use disorders associated with an earlier age at onset of psychosis? A study in first episode schizophrenia

INTRODUCTION

The purpose of this study is to determine if an earlier age at onset of positive symptoms in schizophrenia is associated with cannabis use disorders (CUD).

METHODS

49 first-episode schizophrenia subjects with CUD were compared to 51 first-episode schizophrenia subjects with no substance use disorders for demographic and clinical variables. A multivariate logistic regression was performed to determine the joint relationship between variables significantly associated with CUD on univariate testing and ascertain if these variables independently predict CUD. Significance level was set at p<0.05.

RESULTS

74% of CUD subjects had the onset of CUD before the onset of positive symptoms. Compared to non-substance abusing subjects, CUD subjects were predominantly male, younger at study entry, had an earlier age at onset of positive symptoms, less educational attainment, a lower self-socioeconomic status, better premorbid childhood social adjustment, a trend for poorer premorbid childhood academic adjustment, less motor abnormalities but more severe hallucinations and delusions. In the multivariate analysis, only male gender, worse socio-economic status, better premorbid childhood social adjustment, and more severe positive symptoms at study entry were associated with a lifetime history of CUD.

DISCUSSION

Although cannabis use precedes the onset of illness in most patients, there was no significant association between onset of illness and CUD that was not accounted for by demographic and clinical variables. Previous studies implicating CUD in the onset of schizophrenia may need to more comprehensively assess the relationship between CUD and schizophrenia, and take into account additional variables that we found associated with CUD.

Cannabis use disorders in schizophrenia: effects on cognition and symptoms

OBJECTIVE

Despite the controversy surrounding the possible causal link between cannabis use and the onset of schizophrenia (SZ), data seeking to elucidate the effect of cannabis use disorders (CUDs) on the clinical presentation of SZ have produced mixed results. Although several studies have suggested that CUD in patients with SZ may be associated with variation in cognitive function, clinical presentation and course of illness, the effects have been inconsistent.

METHODS

We retrospectively ascertained a large cohort (N=455) of SZ patients with either no history of a CUD (CUD-; N=280) or a history of CUD (CUD+; N=175). The groups were initially compared on key demographic variables including sex, race, age, age at onset of SZ, parental socioeconomic status, premorbid IQ, education level and global assessment of functioning. Covarying for any observed differences in demographic variables, we then compared groups on lifetime measures of psychotic symptoms as well as a brief battery of neurocognitive tests.

RESULTS

Compared to the CUD- group the CUD+ group demonstrated significantly better performance on measures of processing speed (Trail Making Tests A and B), verbal fluency (animal naming) and verbal learning and memory (California Verbal Learning Test). Moreover, the CUD+ group had better GAF scores than the CUD group.

CONCLUSIONS

Collectively, these findings suggest that SZ patients with comorbid CUD may represent a higher functioning subgroup of SZ. Future prospective studies are needed to elucidate the nature of this relationship.

Temporal relationship of first-episode non-affective psychosis with cannabis use: a clinical verification of an epidemiological hypothesis

BACKGROUND

We analyzed the association of age at onset of psychosis treatment (AOPT) with having a history of cannabis use in patients with a first episode of non-affective psychosis. We also investigated the impact on the AOPT of exposure to cannabis in adolescence, compared with young adulthood, and of the additional exposure to cocaine.

METHOD

We recruited 112 consecutive patients (66 men and 46 women; age range, 18-57years) with a first psychotic episode. The composite international diagnostic interview (CIDI) was used to assess drug use and to define the age at onset of heaviest use (AOHU) of a drug, defined as the age when drug was used the most for each patient. The effect of cannabis and cocaine AOHU on AOPT was explored through Kruskal-Wallis and Mann-Whitney tests, and logistic regression. Sex-adjusted cumulative hazard curves and Cox regression models were used to compare the AOPT of patients with and without a history of cannabis use, or associated cocaine use.

RESULTS

We found that the AOPT was significantly associated with the use of cannabis, independently of sex, use of cocaine, tobacco smoking or excessive alcohol consumption. There was a dose-response relationship between cannabis AOHU and AOPT: the earlier the AOHU the earlier the AOPT. Hazard curves showed that patients with a history of cannabis use had a higher hazard of having a first-episode psychosis than the rest of the patients (sex-adjusted log-rank chi(2)=23.43, df=1, p<0.001). Their respective median AOPT (25th, 75th percentiles) were 23.5 (21, 28) and 33.5years (27, 45) (for log-transformed AOPT, t=5.6, df=110, p<0.001). The sex-adjusted hazard ratio of psychosis onset comparing both groups was 2.66 (95% CI, 1.74-4.05).

CONCLUSIONS

Our results are in favor of a catalytic role for cannabis use in the onset of psychosis.

Executive function in schizophrenia: influence of substance use disorder history

Cognitive function in schizophrenia has been associated with different sociodemographic and clinical variables. Substance use disorder (SUD) history has also been associated with cognition in schizophrenia; however, contradictory results have been found regarding its influence on cognitive function. Our aim was to study the relationship between executive function and a) age, b) duration of illness, c) number of psychotic episodes, d) positive symptoms, and e) negative symptoms, in a sample of schizophrenic patients, and secondly to study whether these relationships persisted after stratification of the sample according to the presence or absence of SUD history. A final sample of 203 schizophrenic patients were evaluated for psychotic symptoms using the PANSS, and assessed using a neuropsychological battery to calculate a composite executive function score. Linear regression analyses were performed, with this executive score as the dependent variable, and age, duration of illness, number of psychotic episodes, positive PANSS score and negative PANSS score as independent variables. For the total sample, the regression model showed three variables to be significant predictors of the executive score: age (p=0.004), number of episodes (p=0.027), and PANSS negative score (p=0.003). However, once the sample was stratified, the regression model showed age (p=0.011) and number of episodes (p=0.011) to be predictor variables for the executive score in the group of schizophrenic patients with SUD history, while age (p=0.028) and PANSS negative score (p=0.006) were predictors in the group of schizophrenic patients without such history. These findings highlight the importance of considering SUD history in studies of cognitive function in schizophrenia.

Cannabis use and cognition in schizophrenia

People with schizophrenia frequently report cannabis use, and cannabis may be a risk factor for schizophrenia, mediated through effects on brain function and biochemistry. Thus, it is conceivable that cannabis may also influence cognitive functioning in this patient group. We report data from our own laboratory on the use of cannabis by schizophrenia patients, and review the existing literature on the effects of cannabis on cognition in schizophrenia and related psychosis. Of the 23 studies that were found, 14 reported that the cannabis users had better cognitive performance than the schizophrenia non-users. Eight studies reported no or minimal differences in cognitive performance in the two groups, but only one study reported better cognitive performance in the schizophrenia non-user group. Our own results confirm the overall impression from the literature review of better cognitive performance in the cannabis user group. These paradoxical findings may have several explanations, which are discussed. We suggest that cannabis causes a transient cognitive breakdown enabling the development of psychosis, imitating the typical cognitive vulnerability seen in schizophrenia. This is further supported by an earlier age of onset and fewer neurological soft signs in the cannabis-related schizophrenia group, suggesting an alternative pathway to psychosis.

First-episode drug-induced psychosis: a medium term follow up study reveals a high-risk group

BACKGROUND

Little is known about first-episode drug-induced psychosis (F19.5).

OBJECTIVES

To examine the incidence, course, diagnostic stability, and outcomes of first-episode drug-induced psychosis (F19.5), and compare with first-episode schizophrenia (F20-21).

METHOD

An observational database was set up on all patients aged 16 and over with a first episode psychosis living in a county in Northern England between October 1998 and October 2005. Data were collected at presentation and annual follow-up. Information on patients with an ICD-10 diagnosis of either drug-induced psychosis (F19.5) or schizophrenia (F20) was compared.

RESULTS

There was no significant difference between the two groups in levels of hospitalisation and violence. Patients with a drug-induced psychosis were more likely to lose contact with services, and a third developed a schizophrenia-spectrum disorder.

CONCLUSIONS

Increased attention should be paid to maintaining engagement with this high-risk group who have a high rate of transition to schizophrenia.