Morbidity and mortality in schizophrenia with comorbid substance use disorders

Abstract

Objective Schizophrenia is highly comorbid with substance use disorders (SUD) but large epidemiological cohorts exploring the prevalence and prognostic significance of SUD are lacking. Here, we investigated the prevalence of SUD in patients with schizophrenia in Finland and Sweden, and the effect of these co‐occurring disorders on risks of psychiatric hospitalization and mortality. Methods 45,476 individuals with schizophrenia from two independent national cohort studies, aged <46 years at cohort entry, were followed during 22 (1996–2017, Finland) and 11 years (2006–2016, Sweden). We first assessed SUD prevalence (excluding smoking). Then, we performed Cox regression on risk of psychiatric hospitalization and all‐cause and cause‐specific mortality in SUD compared with those without SUD. Results The prevalence of SUD ranged from 26% (Finland) to 31% (Sweden). Multiple drug use ( n = 4164, 48%, Finland; n = 3268, 67%, Sweden) and alcohol use disorders ( n = 3846, 45%, Finland; n = 1002, 21%, Sweden) were the most prevalent SUD, followed by cannabis. Any SUD comorbidity, and particularly multiple drug use and alcohol use, were associated with 50% to 100% increase in hospitalization (aHR any SUD: 1.53, 95% CI = 1.46–1.61, Finland; 1.83, 1.72–1.96, Sweden) and mortality (aHR all‐cause mortality: 1.65, 95% CI = 1.50–1.81, Finland; 2.17, 1.74–2.70, Sweden) compared to individuals without SUD. Elevated mortality risks were observed especially for suicides and other external causes. All results were similar across countries. Conclusion Co‐occurring SUD, and particularly alcohol and multiple drug use, are associated with high rates of hospitalization and mortality in schizophrenia. Preventive interventions should prioritize detection and tailored treatments for these comorbidities, which often remain underdiagnosed and untreated.

Mortality in people with schizophrenia: a systematic review and meta‐analysis of relative risk and aggravating or attenuating factors

“…An initial search retrieved 8,345 abstracts; removal of duplicates resulted in 6,390 abstracts for review. Of these, a total of 135 studies 5‐10,38‐166 were included, after excluding 463 articles upon full text assessment (see Figure 1, Table 1 and supplementary information). We ultimately included 4,536,447 individuals with schizophrenia who were compared with 1,115,600,059 control subjects from the general population.…”

Place of the partial dopamine receptor agonist aripiprazole in the management of schizophrenia in adults: a Delphi consensus study

“…The prevalence of comorbid addictive disorders in patients with schizophrenia is high compared to the general population, and many of these patients present with multiple addictions [ 112 ]. These patients are a particular challenge for the treating psychiatrist, as they may have poorer treatment persistence [ 113 ] and compliance [ 114 ], poorer symptom control [ 115 ] or more pronounced extrapyramidal symptoms [ 116 ], poorer prognosis [ 114 , 117 ], higher mortality [ 118 ] and poorer social integration [ 115 ] than patients without addictive comorbidity. Treatment of patients with schizophrenia with FGAs may aggravate addictive comorbidity and compromise attempts to stop or reduce substance use [ 119 , 120 ].…”

Psychosis in Women: Time for Personalized Treatment

“…As already reported, women show better outcomes, particularly during the first three years of treatment delivered at early intervention services, usually due to more favorable premorbid profiles and baseline characteristics. Moreover, the higher rates of mortality in patients with schizophrenia and comorbid substance use disorder (SUD) compared to those without SUD should be taken into account [37]. SUDs are dramatically oriented towards a male use, especially in adolescents and young adults presenting with psychotic symptoms [39].…”