Depression in alcoholic schizophrenic patients

Investigation of convergent and divergent genetic influences underlying schizophrenia and alcohol use disorder

BACKGROUND

Alcohol use disorder (AUD) and schizophrenia (SCZ) frequently co-occur, and large-scale genome-wide association studies (GWAS) have identified significant genetic correlations between these disorders.

METHODS

We used the largest published GWAS for AUD (total cases = 77 822) and SCZ (total cases = 46 827) to identify genetic variants that influence both disorders (with either the same or opposite direction of effect) and those that are disorder specific.

RESULTS

We identified 55 independent genome-wide significant single nucleotide polymorphisms with the same direction of effect on AUD and SCZ, 8 with robust effects in opposite directions, and 98 with disorder-specific effects. We also found evidence for 12 genes whose pleiotropic associations with AUD and SCZ are consistent with mediation via gene expression in the prefrontal cortex. The genetic covariance between AUD and SCZ was concentrated in genomic regions functional in brain tissues (p = 0.001).

CONCLUSIONS

Our findings provide further evidence that SCZ shares meaningful genetic overlap with AUD.

Clinical correlates of subsyndromal depression in African American individuals with psychosis: The relationship with positive symptoms and comorbid substance dependence

Patients with psychosis exhibit subsyndromal depressive symptoms during the course of illness and yet the clinical correlates of these symptoms remain under-investigated. We aimed to investigate the clinical correlates of subsyndromal depression in psychosis including the extent to which they mediate commonly observed comorbid substance dependence. We developed a model of depression in a non-clinical sample recruited via Amazon's Mechanical Turk (N = 266), and confirmed that model in a locally recruited African-American clinical sample comprising psychotic and non-psychotic individuals (N = 256). Using scores from this model we tested: the strength of relationships between depressive symptomatology and positive, negative and disorganized symptoms in a range of psychotic disorders; whether depressive symptoms were higher in individuals with affective psychoses versus schizophrenia; and if depressive symptomatology mediated the relationship between psychosis and substance dependence. Subsyndromal depressive symptomatology was significantly higher in individuals with psychosis than without psychosis, but did not significantly differ between affective and non-affective psychotic groups. Depressive symptomatology was significantly related to positive (but not negative or disorganized) psychotic symptoms, and mediated the relationship between psychosis and substance dependence. The present study underlines the importance of assessing subsyndromal depression in patients with psychosis, and generates a number of testable predictions for future work. In particular, the examination of the relationships between comorbid psychopathology, namely depression and substance abuse, may improve insight into the neurobiology of psychosis.

Genetic correlation between smoking behaviors and schizophrenia

Nicotine dependence is highly comorbid with schizophrenia, and the etiology of the comorbidity is unknown. To determine whether there is a genetic correlation of smoking behavior with schizophrenia, genome-wide association study (GWAS) meta-analysis results from five smoking phenotypes (ever/never smoker (N=74,035), age of onset of smoking (N=28,647), cigarettes smoked per day (CPD, N=38,860), nicotine dependence (N=10,666), and current/former smoker (N=40,562)) were compared to GWAS meta-analysis results from schizophrenia (N=79,845) using linkage disequilibrium (LD) score regression. First, the SNP heritability (h²_g) of each of the smoking phenotypes was computed using LD score regression (ever/never smoker h²_g=0.08, age of onset of smoking h²_g=0.06, CPD h²_g=0.06, nicotine dependence h²_g=0.15, current/former smoker h²_g=0.07, p<0.001 for all phenotypes). The SNP heritability for nicotine dependence was statistically higher than the SNP heritability for the other smoking phenotypes (p<0.0005 for all two-way comparisons). Next, a statistically significant (p<0.05) genetic correlation was observed between schizophrenia and three of the five smoking phenotypes (nicotine dependence r_g=0.14, CPD r_g=0.12, and ever/never smoking r_g=0.10). These results suggest that there is a component of common genetic variation that is shared between smoking behaviors and schizophrenia.

Comorbidity of severe psychotic disorders with measures of substance use

IMPORTANCE

Although early mortality in severe psychiatric illness is linked to smoking and alcohol, to our knowledge, no studies have comprehensively characterized substance use behavior in severe psychotic illness. In particular, recent assessments of substance use in individuals with mental illness are based on population surveys that do not include individuals with severe psychotic illness.

OBJECTIVE

To compare substance use in individuals with severe psychotic illness with substance use in the general population.

DESIGN, SETTING, AND PARTICIPANTS

We assessed comorbidity between substance use and severe psychotic disorders in the Genomic Psychiatry Cohort. The Genomic Psychiatry Cohort is a clinically assessed, multiethnic sample consisting of 9142 individuals with the diagnosis of schizophrenia, bipolar disorder with psychotic features, or schizoaffective disorder, and 10,195 population control individuals.

MAIN OUTCOMES AND MEASURES

Smoking (smoked >100 cigarettes in a lifetime), heavy alcohol use (>4 drinks/day), heavy marijuana use (>21 times of marijuana use/year), and recreational drug use.

RESULTS

Relative to the general population, individuals with severe psychotic disorders have increased risks for smoking (odds ratio, 4.6; 95% CI, 4.3-4.9), heavy alcohol use (odds ratio, 4.0; 95% CI, 3.6-4.4), heavy marijuana use (odds ratio, 3.5; 95% CI, 3.2-3.7), and recreational drug use (odds ratio, 4.6; 95% CI, 4.3-5.0). All races/ethnicities (African American, Asian, European American, and Hispanic) and both sexes have greatly elevated risks for smoking and alcohol, marijuana, and drug use. Of specific concern, recent public health efforts that have successfully decreased smoking among individuals younger than age 30 years appear to have been ineffective among individuals with severe psychotic illness (interaction effect between age and severe mental illness on smoking initiation, P = 4.5 × 105).

CONCLUSIONS AND RELEVANCE

In the largest assessment of substance use among individuals with severe psychotic illness to date, we found the odds of smoking and alcohol and other substance use to be dramatically higher than recent estimates of substance use in mild mental illness.

Extrapyramidal symptoms in substance abusers with and without schizophrenia and in nonabusing patients with schizophrenia

Extrapyramidal symptoms (EPS) such as parkinsonism, dystonia, dyskinesia, and akathisia are conditions of impaired motor function, which are associated with chronic antipsychotic treatment in schizophrenia. In addition, EPS is often exacerbated by psychoactive substance (PAS) abuse, which is frequently observed in this population. Few studies, however, have investigated the contribution of PAS abuse on EPS in PAS-abusers without comorbid psychosis. This study compared the occurrence of EPS in outpatient schizophrenia patients with (DD group; n= 36) and without PAS abuse (SCZ group; n = 41) as well as in nonschizophrenia PAS abusers undergoing detoxification [substance use disorder (SUD) group; n = 38]. Psychiatric symptoms were measured using the Positive and Negative Syndrome Scale and the Calgary Depression Scale for schizophrenia. Extrapyramidal symptoms were evaluated with the Extrapyramidal Symptoms Rating Scale and the Barnes Akathisia Scale. SUD diagnoses were complemented with urine drug screenings. We found that DD patients exhibited significantly more parkinsonism than SCZ patients. Our subanalyses revealed that cocaine and alcohol abuse/dependence was responsible for the increase in parkinsonism in DD patients. Additionally, we found that SUD individuals exhibited significantly more akathisia than SCZ patients. In these latter individuals, subanalyses revealed that alcohol and cannabis abuse/dependence was responsible for the increase in akathisia. Our results suggest that PAS abuse is a contributor to EPS in individuals with and without schizophrenia.

Meta-analysis of depressive symptoms in dual-diagnosis schizophrenia

Substance abuse is highly prevalent in schizophrenia and associated with numerous negative consequences. While studies have regularly reported more severe depressive symptoms in addicted schizophrenia patients relative to non-abusing patients, some studies have not corroborated this finding. The current meta-analysis was performed to quantify the relative severity of depressive symptoms in dual-diagnosis schizophrenia. A search of the literature using computerized engines was undertaken. Studies were retained in the analysis if (i) they assessed depressive symptoms using validated scales specific to depression (e.g. Hamilton Depression Rating Scale); and (ii) groups of schizophrenia patients were divided according to substance use disorders (alcohol, amphetamines, cannabis, cocaine, hallucinogens, heroin and/or phencyclidine). According to the inclusion criteria, 20 studies were available for mathematical analysis. A small, positive and significant effect size estimate (n =3283; 1680 dual diagnosis; 1603 single diagnosis; adjusted Hedges's g =0.292; p =0.003) was obtained, within a random-effect model, suggesting that some dual-diagnosis patients experience more severe depressive symptoms than single-diagnosis patients. This significant difference was found only for studies using the Hamilton Depression Rating Scale but not for other depression scales. The results of the present meta-analysis suggest that addicted schizophrenia patients experience more severe depressive symptoms compared to non-abusing patients, but that the difference is smaller than commonly assumed. The meta-analysis also shows that the significance of results is related to the scale used to measure depressive symptoms. These results have methodological implications for future studies of depressive symptoms in dual-diagnosis patients, and potential implications for the prevention and treatment of depressive symptoms in schizophrenia.

Olanzapine treatment for patients with schizophrenia and substance abuse

The objective of this study was to evaluate the efficacy and safety of olanzapine in patients with schizophrenia and comorbid substance abuse disorders. Thirty patients who met DSM-IV criteria for schizophrenia or schizoaffective disorder as well as criteria for substance abuse or substance dependence, were treated in a 12-month prospective, open-label trial of olanzapine. Patients were evaluated with multiple efficacy and safety measures at baseline and then monthly thereafter. Statistically significant improvement was noted in psychopathology, levels of hope, and safety measures. Seventy percent (n = 21) of the patients achieved early full substance abuse remission at the end of the study period, while 30% (n = 9) achieved early partial substance abuse remission. Our results indicate that olanzapine treatment improved psychopathology, increased hopefulness, and reduced antipsychotic-associated side effects. The benefits observed with olanzapine treatment may contribute to the patients' substance abuse remission.

Addiction and schizophrenia

Epidemiologic studies in the general population and those based on the clinical assessment of schizophrenic populations have revealed a high degree of overlap between schizophrenia and addictive disorders. The abuse of psychoactive substances (including alcohol) throughout life is so frequent (50%) that the possibility of a specific link inevitably arises. Various hypotheses have been suggested to explain the high co-morbidity between schizophrenia and addiction: 1) The social-environmental hypothesis has been developed but studies have provided poor evidence to validate it. 2) The possible shared biological vulnerability between schizophrenia and addictions led researchers to explore common genetic determinants and study the involvement of the dopaminergic and opioid systems in the aetiology of both schizophrenia and the abuse of and dependence on psychoactive drugs. 3) Finally, the theory of self-medication suggests that schizophrenics may be attempting to counter the deficit linked to their disorders by using the substances they take or their dependency-type behaviour to cope with their emotional problems. The clinical profile of schizophrenic addicts does seem to display some distinctive features, such as the high level of depressive co-morbidity, very high nicotine and alcohol dependence, with a very poor prognosis. These patients are difficult to manage; the possibility of pharmacologic interactions between the substances they are taking and neuroleptic medication calls for prudence, and their compliance is also poor. Addictive disorders in schizophrenics are currently a topic of active research intended to lead to identifying specific treatments. The early identification of addictive disorders in schizophrenics should make it possible to limit their development and improve the prognosis.

Toward a rational pharmacotherapy of comorbid substance abuse in schizophrenic patients

The prevalence of substance abuse is elevated among schizophrenic patients. When free of illicit substances and sober, substance-abusing schizophrenic patients may have a better prognosis than other frequently hospitalized schizophrenic patients. However, the cost of substance abuse is great in terms of rehospitalization, homelessness, risk of other medical illness, disruption of social and vocational function, exacerbation of symptoms, suicide, and increased health care expenses. Important recent developments in medications for reducing substance abuse in nonschizophrenic populations make it timely to consider factors that might contribute to substance abuse among schizophrenic patients. This review will focus on substances most frequently abused by schizophrenic patients: nicotine, alcohol, cannabis, and psychostimulants. It concentrates on two conceptual foci: "self-medication hypotheses" and "comorbid addiction vulnerability hypotheses". The relationship between these hypotheses and possible pharmacotherapeutic approaches for substance-abusing schizophrenic patients will be considered.