Impact of synthetic cannabinoid use on hospital stay in patients with bipolar disorder versus schizophrenia, or other psychotic disorders

Highlights

• This study examined the impact of synthetic cannabinoid (SC) use on hospital stay.

• Patients with bipolar, schizophrenia, or other psychotic disorders were included.

• Patients with SC use had shorter stays and received lower doses of antipsychotics.

• The inclusion of clinical diagnoses did not alter this finding.

Abstract

Synthetic cannabinoid products have become popular and have led to an increased number of patients presenting to emergency departments and psychiatric hospitals. The purpose of this study was to evaluate the impact of synthetic cannabinoid use at admission on length of stay and doses of antipsychotics at discharge in individuals with bipolar disorder, schizophrenia and other psychotic disorders. We retrospectively examined medical records of 324 inpatients admitted from January 2014 to July 2015. We found that synthetic cannabinoid use predicted length of stay and antipsychotic dose using structural equation modeling. Further, the association of synthetic cannabinoid use with length of stay was partly mediated by antipsychotic dose. These associations were independent of specific diagnosis. In conclusion, patients with bipolar disorder, schizophrenia, or other psychotic disorders who reported synthetic cannabinoid use at admission had shorter length of stay and received lower doses of antipsychotics, irrespective of clinical diagnoses.

Introduction

Synthetic cannabinoid products are “herbal” mixtures sold around the world since 2004 under brand names such as K2, Spice, and Kush. These products are most commonly smoked as incense, vaporized, or inhaled as liquids using e-cigarettes, or other devices. They produce marijuana-like effects, and are not detected by routine drug screening tests. Synthetic cannabinoids are the most diverse, largest, and fastest growing among the new psychoactive substances sold on the market (United Nations Office on Drugs and Crime, 2015). In the United States, past year prevalence was 6.5% among adults younger than 30 years old in 2011 (United Nations Office on Drugs and Crime, 2016). Synthetic cannabinoids have become the second most commonly used illegal drug by high school seniors in the United States (Johnston et al., 2014). Furthermore, the true prevalence might be much higher than what has been reported as a study reported that only half of the patients that presented to the emergency department with acute synthetic cannabinoid toxicity reported use (Abouchedid et al., 2017). Although the prevalence of synthetic cannabinoid use among individuals with psychotic disorders is still unclear, synthetic cannabinoid products have become popular and reported exposure to these products is increasing (Kunins, 2015, Palamar et al., 2016). More than half of the patients seen at an acute public mental health facility in Australia reported synthetic cannabinoid use (Clancy et al., 2017). A multicenter study carried out in Italian psychiatric care facilities reported that the prevalence of novel psychoactive substances use among psychiatric patients appeared to be higher than in general population and that the most commonly consumed novel psychoactive substances were synthetic cannabinoids (4.5% consumed Spice) (Acciavatti et al., 2017). These results are consistent with a large-scale comparison study between psychiatric patients and matched healthy controls (Martinotti et al., 2014). Surveys indicate that the majority of synthetic cannabinoid users are single, young, Caucasian males (Vandrey et al., 2012, Barratt et al., 2013, Castaneto et al., 2014, Caviness et al., 2015), although this may vary by time and location of the population surveyed. One study found that the average age of users increased steadily over time based on data of New York City Poison Center from 2011 to 2014, and by 2014 the mean age increased to above 30 years (Palamar et al., 2016). Another study reviewed charts of patients that presented to a psychiatric emergency service in New York City in 2014 and reported that synthetic cannabinoid users were mostly non-white homeless males with a median age of 33 years (Manseau et al., 2017).

It is known that bipolar disorder, schizophrenia, and other psychotic disorders are highly comorbid with substance use disorder. Among individuals with schizophrenia or schizophreniform disorder, 47.0% have comorbid substance use disorder (SUD) (Regier et al., 1990). There is a 61% and 48% lifetime prevalence of SUD in individuals with bipolar I and II disorders, respectively, compared to 6% in the general population (Regier et al., 1990). Furthermore, a study that investigated a large cohort of Medicaid beneficiaries (n = 11,185) reported that 22.9% of patients with any type of psychotic disorder, whether bipolar disorder, schizophrenia, or other psychoses, had a co-occurring SUD (Dickey et al., 2002).

Synthetic cannabinoids are 2–200 times more potent than Δ9-tetrahydrocannabinol (THC) (Martín-Calderón et al., 1998; De Petrocellis et al., 2004; Jerry et al., 2012; Castaneto et al., 2014). Synthetic cannabinoid use can result in negative outcomes including psychosis, violent behavior, and deaths (Castaneto et al., 2014, Trecki et al., 2015, Martinotti et al., 2017b, Shafi et al., 2017). Users of synthetic cannabinoids including Spice products showed higher level of aggressiveness than stimulant users in a psychiatric in-patient setting (Martinotti et al., 2017a). A recent study reported that newer synthetic cannabinoid products might generate more harms compared to the older products as the authors investigated drug-focused web-forums between 2008 and 2015 (Lamy et al., 2017). The clinical presentations of synthetic cannabinoid use in patients with pre-existing psychotic disorders have been reported in only a few case studies. For example, 15 patients with either schizophrenia, schizoaffective disorder, or bipolar affective disorder in a forensic and rehabilitative in-patient service reported using a very common synthetic cannabinoid (JWH-018) which was frequently associated with anxiety and psychotic relapses (Every-Palmer, 2011). On the other hand, a report on four male patients with history of schizophrenia following use of a synthetic cannabinoid (AM-2201) indicated that the synthetic cannabinoid resulted in marked worsening of anxiety and mood symptoms, as well as emergence of new psychotic symptoms that were different from those previously reported by the patients (Celofiga et al., 2014).

The relationship between synthetic cannabinoid and psychosis requires further study because the clinical effects of synthetic cannabinoid use in patients with psychotic disorders are diverse and difficult to predict. A study that reviewed 594 digital charts of in-patients admitted to a psychiatric unit in New York found more prominent psychotic features in synthetic cannabinoid users than in cannabis users (Bassir Nia et al., 2016). Few studies report on the impact of synthetic cannabinoid on in-patients with psychotic disorders, although synthetic cannabinoid-induced psychosis is mentioned in the literature. We present a comparative study in a relatively large sample of in-patients with bipolar disorder, schizophrenia, and other psychotic disorders with and without self-reported synthetic cannabinoid use at admission. The purpose of the present study was to examine the impact of synthetic cannabinoid use on hospital length of stay and doses of antipsychotics prescribed at discharge.