Comorbidity of bipolar disorder and substance abuse in Costa Rica: pedigree- and population-based studies

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.

Alcohol misuse in bipolar disorder. A systematic review and meta-analysis of comorbidity rates

Aims:

To assess the comorbidity rates of alcohol use disorders (AUDs) in bipolar disorder (BD) and to explore possible sources of heterogeneity.

Methods:

Studies were identified through database searches. Meta-analytic techniques were employed to aggregate data on lifetime comorbidity and to explore possible sources of heterogeneity. Funnel plots were used to detect publication bias.

Results:

In clinical studies, AUDs affected more than one in three subjects with BD. Significant heterogeneity was found, which was largely explained by the geographical location of study populations and gender ratio of participants. AUDs affected more than one in five women and two in five men.

Conclusion:

AUDs are highly prevalent in BD. Our study revealed a substantial heterogeneity across studies. Further research including control groups is needed. Patients with BD should be assessed for current and previous AUDs.

Prevalence of comorbid bipolar and substance use disorders in clinical settings, 1990-2015: Systematic review and meta-analysis

BACKGROUND

Comorbidity between substance use disorders (SUDs) and bipolar disorder (BD) is highly prevalent to the extent it may almost be regarded the norm. This systematic review and meta-analysis aimed to estimate the prevalence rates of SUDs in treatment seeking patients diagnosed with BD in both inpatient and outpatient settings.

METHODS

A comprehensive literature search of Medline, EMBASE, psychINFO and CINAHL databases was conducted from 1990 to 2015. Prevalence of co-morbid SUDs and BD were extracted and odds ratios (ORs) were calculated using random effects meta-analysis.

RESULTS

There were 151 articles identified by electronic searches that yielded 22 large, multi-site studies and 56 individual studies describing comorbid rates of SUDs amongst community dwelling, BD inpatients or outpatients. The SUDs with the highest prevalence in BD were alcohol use (42%) followed by cannabis use (20%) and other illicit drug use (17%). Meta-analysis showed males had higher lifetime risks of SUDs compared to females. BD and comorbid SUDS were associated with earlier age of onset and slightly more hospitalisations than non-users.

LIMITATIONS

The results do not take into account the possibility that individuals may have more than one comorbid disorder, such as having more than one SUD, anxiety disorder, or other combination. Some of the meta-analyses were based on relatively few studies with high rates of heterogeneity. Most included studies were cross-sectional and therefore causality cannot be inferred.

CONCLUSIONS

This systematic review shows comorbidity between SUDs and bipolar illness is highly prevalent in hospital and community-based samples. The prevalence of SUDs was similar in patients with bipolar I and bipolar II disorders. This study adds to the literature demonstrating that SUDs are common in BD and reinforces the need to provide better interventions and properly conducted treatment trials to reduce the burden conferred by comorbid SUD and BD.

Cannabis use and first manic episode

BACKGROUND

Cannabis is the most commonly abused drug among patients with bipolar disorder. Available data has shown that the risk of psychotic disorders increases with the frequency and intensity of cannabis abuse. The present purpose was to review relevant studies to investigate whether cannabis use can be linked to the onset of mania in bipolar disorder.

METHODS

Articles published between 1972 and December 2013 were searched on Medline and PsychInfo using the following keywords: first manic episode, or onset mania, or bipolar disorder and cannabis. Relevant papers cited in the references of selected articles were further considered for inclusion into the review.

RESULTS

Lifetime use of cannabis among bipolar patients appears to be around 70% and approximately 30% of patients with a bipolar disorder present a comorbidity of cannabis abuse or dependence. Cannabis use is associated with younger age at onset of first mania and with more frequent depressive or manic episodes, although the evidence is somewhat inconsistent. Likewise cannabis consumption is related to poorer outcome and an increased risk of rapid cycling or mixed episodes. In contrast, neuro-cognitive functioning seems to be positively affected in patients with psychiatric comorbidity. While cannabis use often precedes first manic episodes, the causal direction remains to be determined.

LIMITATIONS

Variations in definition of cannabis use/dependence. Lack of controlled studies limiting definite conclusions about a putative causal relationship between cannabis and onset of mania.

CONCLUSIONS

Further investigations are needed to clarify the relationships between cannabis use and first manic episode.

Shared genetic factors influence risk for bipolar disorder and alcohol use disorders

Bipolar disorder and alcohol use disorder (AUD) have a high rate of comorbidity, more than 50% of individuals with bipolar disorder also receive a diagnosis of AUD in their lifetimes. Although both disorders are heritable, it is unclear if the same genetic factors mediate risk for bipolar disorder and AUD. We examined 733 Costa Rican individuals from 61 bipolar pedigrees. Based on a best estimate process, 32% of the sample met criteria for bipolar disorder, 17% had a lifetime AUD diagnosis, 32% met criteria for lifetime nicotine dependence, and 21% had an anxiety disorder. AUD, nicotine dependence and anxiety disorders were relatively more common among individuals with bipolar disorder than in their non-bipolar relatives. All illnesses were shown to be heritable and bipolar disorder was genetically correlated with AUD, nicotine dependence and anxiety disorders. The genetic correlation between bipolar and AUD remained when controlling for anxiety, suggesting that unique genetic factors influence the risk for comorbid bipolar and AUD independent of anxiety. Our findings provide evidence for shared genetic effects on bipolar disorder and AUD risk. Demonstrating that common genetic factors influence these independent diagnostic constructs could help to refine our diagnostic nosology.

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.

Treatment costs and health care utilization for patients with bipolar disorder in a large managed care population

OBJECTIVES

This study measured the treatment cost of bipolar disorder (BPD), decomposed the cost into that portion which was directly BPD-related and that attributable to comorbidities, and compared health-care utilization and costs across groups of patients with different drug regimens.

METHODS

Using a multistate managed-care-organization claims database, a cohort of 67,862 BPD patients were selected and followed for the length of their enrollment between January 1, 1998 and December 31, 2002. All costs associated with the patients' medical claims were adjusted to 2002 dollars using the medical component of Consumer Price Index. Patients were classified into three groups based on their drug regimen: atypical antipsychotics (ATYP), atypical antipsychotics plus mood stabilizers (ATYP + MS), and mood stabilizers only (MS). The Charlson comorbidity index was used to control for comorbid conditions. Using both Poisson and log-linear regression analyses, numbers of hospitalizations, emergency room (ER) visits, and outpatient visits, as well as treatment costs per enrolled month, were regressed on age, sex, medication regimen, and clinical comorbidities.

RESULTS

The mean charge and reimbursement per patient-year were $12,797 and $6581, respectively. Of the treatment cost, 33% was BPD-related, and 67% was attributed to comorbidities. Compared to patients in the MS treatment regimen, higher treatment costs were associated with ATYP (Rate Ratio = 1.24, 95% CI 1.17-1.31) and ATYP + MS (RR = 1.52, 1.47-1.56). Moreover, higher costs were associated with key comorbidities like personality disorder (RR = 1.45, 1.37-1.53). Patients on the ATYP regimen had higher risks of hospitalization (RR = 1.44, 1.33-1.56) and ER visits (RR = 1.15, 1.04-1.27), but lower risk of outpatient visits (RR = 0.81, 0.76-0.86).

CONCLUSIONS

Controlling treatment costs for BPD patients requires focusing on patients with key comorbidities and monitoring the association between treatment regimen and resource use.

Cannabis use and expression of mania in the general population

BACKGROUND

Cannabis use is common in patients with bipolar disorder, however little is known about cannabis as a risk factor for mania. In order to investigate the association between exposure to cannabis and subsequent development of manic symptoms whilst controlling for psychotic symptoms, a longitudinal population-based study was carried out.

METHODS

4815 individuals aged 18 to 64 years were interviewed using the Composite International Diagnostic Interview at baseline, 1 year follow up and 3 year follow up, including assessment of substance use, manic symptoms and psychotic symptoms.

RESULTS

Use of cannabis at baseline increased the risk for manic symptoms during follow-up (adjusted OR 2.70, 95% CI: 1.54, 4.75), adjusted for age, sex, educational level, ethnicity, single marital status, neuroticism, use of other drugs, use of alcohol, depressive symptoms and manic symptoms at baseline. The association between cannabis use and mania was independent of the prevalence and the incidence of psychotic symptoms. There was no evidence for reverse causality, as manic symptoms at baseline did not predict the onset of cannabis use during follow-up (OR = 0.35, 95% CI: 0.03, 3.49).

LIMITATIONS

As 3 years is a relative short period of follow-up, long-term effects of cannabis use on mania outcomes could not be detected.

CONCLUSION

The results suggest that cannabis use may affect population expression of manic symptoms (and subsequent risk to develop bipolar disorder [Regeer, E.J., Krabbendam, L., R, DE Graaf, Ten Have, M., Nolen, W.A., Van Os, J., 2006. A prospective study of the transition rates of subthreshold (hypo)mania and depression in the general population. Psychol Med, 1-9.]). These findings may not be due to the emergence of psychotic symptoms or the effects of self-medication.

Linkage disequilibrium analyses in the Costa Rican population suggests discrete gene loci for schizophrenia at 8p23.1 and 8q13.3

Linkage studies using multiplex families have repeatedly implicated chromosome 8 as involved in schizophrenia etiology. The reported areas of linkage, however, span a wide chromosomal region. The present study used the founder population of the Central Valley of Costa Rica and phenotyping strategies alternative to DSM-IV classifications in attempts to further delimitate the areas on chromosome 8 that may harbor schizophrenia susceptibility genes. A linkage disequilibrium screen of chromosome 8 was performed using family trios of individuals with a history of psychosis. Four discrete regions showing evidence of association (nominal P values less than 0.05) to the phenotype of schizophrenia were identified: 8p23.1, 8p21.3, 8q13.3 and 8q24.3. The region of 8p23.1 precisely overlaps a region showing strong evidence of linkage disequilibrium for severe bipolar disorder in Costa Rica. The same chromosomal regions were identified when the broader phenotype definition of all individuals with functional psychosis was used for analyses. Stratification of the psychotic sample by history of mania suggests that the 8q13.3 locus may be preferentially associated with non-manic psychosis. These results may be helpful in targeting specific areas to be analyzed in association-based or linkage disequilibrium-based studies, for researchers who have found evidence of linkage to schizophrenia on chromosome 8 within their previous studies.