Background
The Diagnostic and Statistical Manual (DSM) –IV [
1] describes two distinct disorders of pathological alcohol use: alcohol abuse and alcohol dependence. The newer DSM-5 [
2] however integrates the two disorders from DSM-IV into a single disorder: Alcohol Use Disorder (AUD) with mild, moderate, severe and other sub-classifications. The focus of the current paper; ‘hazardous drinking’, is defined as “a pattern of alcohol consumption that increases the risk of harmful consequences for the user or others” [
3]. That is to say, it is a subthreshold disorder [
4], not yet meeting the clinical threshold to be considered an AUD. In a meta-analytic review, Moyer and colleagues [
5] suggest that brief interventions are effective in patients with less severe alcohol use, but not in those with more severe alcohol use. This seems to suggest that early interventions for people with hazardous alcohol use might be clinically advantageous.
People with schizophrenia have been found to be more likely to have alcohol problems than the general population [
6‐
8]. Coupled with the knowledge that AUDs might further exacerbate the symptoms of schizophrenia, it seems important to further investigate alcohol use among people with schizophrenia or psychosis. First episode psychosis (FEP) in particular seems to mark a critical juncture in the treatment of schizophrenia. Past research seems to indicate that interventions soon after the onset of the first episode of psychosis are associated with better recovery (reduced symptoms and improved overall functioning) [
9], especially when compared to traditional care [
10]. Thus, this period also provides an opportunity for early intervention to treat comorbid physical and other mental health disorders including addictions.
AUDs have been found to be associated with a host of negative outcomes, particularly in patients with schizophrenia and psychosis. For example, individuals with FEP or schizophrenia, and comorbid AUD have been associated with greater positive symptoms [
11‐
13]. Amongst associated socio-demographic factors, AUD has been found to be associated with being male in FEP [
14] and lower education amongst individuals diagnosed with schizophrenia [
15]. Additionally, being a current smoker was also associated with alcohol dependence among those with psychosis [
16].
The prevalence of hazardous alcohol use seems to vary between Western and Asian countries. For example, the prevalence of hazardous alcohol use was reported to be 24% amongst a sample of psychiatric outpatients in Sweden [
17] and 26% amongst a sample of outpatients with FEP in Canada [
18]. On the other hand, the prevalence of hazardous alcohol use was reported to be 10.5% in a sample of psychiatric outpatients in Taiwan [
19] and 5.5% in a sample of outpatients with schizophrenia in India [
20]. As such, one might hypothesise the hazardous alcohol use in a population of FEP patients in Singapore to be lower than those reported in Western countries. While there have been previous studies conducted that have examined AUDs amongst the general population in Singapore [
21], AUDs amongst inpatients of a general hospital in Singapore [
22] and hazardous alcohol use amongst psychiatric outpatients [
23] in Singapore, this is the first study to date to examine hazardous alcohol use among patients with FEP in Singapore.
This study aimed to investigate the prevalence of hazardous alcohol use amongst an outpatient population with FEP in Singapore. Additionally, we also sought to investigate socio-demographic and clinical correlates of hazardous alcohol use amongst those with FEP. Lastly, we aimed to investigate the relationships between quality of life and hazardous alcohol use.
Discussion
The 12-month prevalence of hazardous alcohol use in the population of patients with FEP in this study was found to be 12.9%. Having no history of smoking (vs with a history of smoking) and having a clinical diagnosis of brief psychotic disorder (vs schizophrenia spectrum) was found to reduce the likelihood of having hazardous alcohol use. Hazardous alcohol use was also associated with lower negative symptom scores on the PANSS scale. Lastly, hazardous alcohol use was found to significantly predict three out of the four domains of quality of life (physical health, social relationships and environment domains of quality of life).
The prevalence of hazardous alcohol use reported in this study (12.9%) is consistent with the trend from past literature that has indicated the prevalence of AUDs to be higher among a psychiatric population than in the general population [
27]. While there are no studies that have reported to date hazardous alcohol use among the general population in Singapore, the prevalence of hazardous alcohol use reported in the current study can be compared against the prevalence of hazardous alcohol (measured by an AUDIT score of 8 or greater) amongst inpatients in a general hospital in Singapore (2.8%) [
22]. One explanation for the higher prevalence of hazardous alcohol use amongst people with schizophrenia than in the general (non-psychiatric) population may be explained through the self-medication hypothesis. The self-medication hypothesis, postulates that people use substances such as alcohol as a means of self-regulating their distressing emotions [
28,
29]. In a qualitative study involving a semi-structured interview design, participants with schizophrenia and a history of AUD were more likely to cite the use of alcohol to relieve symptoms of depression, and problems or worries than those without comorbid AUD [
30]. Additionally, the reported prevalence in this paper is also consistent with the trend of lower prevalence of hazardous alcohol use in Asian countries compared to other Western countries as reported earlier in this paper. It is also consistent with generally lower prevalence of alcohol consumption in Asian countries compared to Western countries.
Having a clinical diagnosis of brief psychotic disorder was found to significantly reduce the odds of hazardous alcohol use. This is a new finding that has not been found before to the best of our knowledge. Having said that, a large portion of the study sample (n = 149, 53.2%) had a diagnosis of schizophrenia spectrum disorder. Comparatively, a much smaller portion of the sample had a diagnosis of brief psychotic disorder (n = 32, 11.4%). As such, any conclusions about the associations with a diagnosis of brief psychotic episode and hazardous alcohol use should be interpreted with caution. Future work in this area could consider performing similar studies with stratified sampling for diagnosis of the participants.
Hazardous alcohol use was found to be associated with lower negative symptom scores, indicative of fewer problems with social withdrawal, blunted affect, difficulties in abstract thinking and stereotyped thinking. While this might come across as a surprising finding, it is not new [
31]. Tamo and colleagues found that patients with comorbid schizophrenia and substance use disorders (inclusive of AUDs) had lower negative symptom scores on the PANSS than those without a substance use disorder. In another study by Batki and colleagues [
32], it was found that in a sample of participants with alcohol dependence, higher negative symptoms of schizophrenia were associated with lower frequency of alcohol drinking, alcohol cravings and quality of alcohol “high”. All the three study findings seem consistent and might be explained by the social nature of drinking behaviours especially in a younger sample group. Hence, individuals with less social withdrawal (lower negative symptom scores) might be better able to seek out opportunities to indulge in hazardous alcohol use. However, because of the cross-sectional nature of the current study, causal attributions cannot be made and it might well also be possible that hazardous alcohol use reduces negative symptom scores. Hence, further longitudinal research is still needed to validate this form of social explanation for drinking behaviours.
Additionally, individuals with a history of smoking were found to be more likely to report hazardous alcohol use. This finding is consistent with previous research indicating the frequent co-occurrence of smoking and excess alcohol use [
23,
33,
34]. One study suggests that people who consider themselves to be risk takers were more likely to share a genetic risk with schizophrenia and be smokers [
35]. This might indicate that risk taking behaviours such as hazardous alcohol use and smoking might have a genetic link with schizophrenia. In terms of health outcomes, consuming excessive alcohol and smoking seems to be particularly detrimental. A longitudinal study by Hart and colleagues [
36] found that men who both smoked and drank more than 15 units of alcohol per week were at the highest risk of all causes of death investigated in the study. This highlights the need to screen for the co-occurrence of excessive alcohol use and cigarette smoking among individuals with FEP and deliver appropriate interventional services as this group seems particularly vulnerable to worse health outcomes.
Importantly, hazardous alcohol use was able to predict three out of the four domains of quality of life (physical health, social relationships and environmental domains). This is a significant finding that highlights the seriousness of hazardous alcohol use in the current sample. The physical health domain of the WHOQOL-BREF includes items on pain, energy levels, mobility, sleep and capacity for daily living activities. The association between alcohol consumption and poorer physical health has been generally well-established in research [
37], including disturbances to sleep [
38] and impaired daily activities [
39]. The social relationships domain of the scale includes items on satisfaction with personal relationships and the social support being received. Additionally, the environmental domain of the WHOQOL-BREF includes items on the home environment, access to transport, opportunity for leisure activities, satisfaction with finances and access to health services. Poor social and physical environments have often been associated with alcohol use amongst those with schizophrenia and psychosis with many living in poverty, and limited opportunities, as well as facing issues of stigma and segregation due to the illness, often exacerbated with the AUDs [
40]. This is in addition to the already established findings that AUDs adversely affect marital satisfaction and stability, as well as the family institution [
41]. The findings from the current paper suggest the pervasive negative effect of hazardous alcohol use in people with psychosis and highlight the need for added support, focused on individuals with psychosis living in worse physical environments, with problematic relationships and with comorbid hazardous alcohol use.
The mean values reported in the current study of the quality of life domains can be directly compared to an earlier study by Cheung and colleagues in Singapore [
42]. Their study reported mean quality of life scores segregated by the four domains in a sample comprising those from the general population (
N = 892) as well as from tertiary hospitals with varying health conditions (diabetes, heart disease, mental illness etc.) (
N = 424). The overall mean scores for quality of life from the sample in the current study was lower for all the four domains of quality of life (physical health, psychological health, social relationships and environment domains), when compared to the pooled sample in the study by Cheung et al. Given that the sample population in the current study have psychosis and are within the first 3 months of diagnosis, it is an expected finding. However, it is important to note that the hazardous alcohol use group in particular in the current study have much lower scores of quality of life which is a cause for concern and an opportunity for early intervention.
The prevalence of hazardous alcohol use amongst patients with FEP reported in the current study can be compared to a similar study which examined hazardous alcohol use amongst psychiatric outpatients in Singapore (albeit with a sample population with a diagnosis of schizophrenia or depression) [
23]. The prevalence of hazardous alcohol use in the current study among outpatients with FEP was found to be almost double (12.9%) compared to patients with schizophrenia (6.4%). This finding again supports the self-medication hypothesis, especially given that patients with FEP in our study were recruited within 3 months of diagnosis. It might be hypothesised that patients with a more recent onset of psychosis might initially use alcohol to cope with the distressing symptoms of psychosis but might grow less reliant on it, with psychiatric treatment filling in that function. However, the consistent finding of hazardous alcohol being associated with poorer quality of life in the physical health domain in both studies suggest that the effects of hazardous alcohol use on physical health does not get better even with continued psychiatric treatment.
The findings of this paper highlight the need for screening, intervention and appropriate referral for patients. Literature has indicated positive results thus far on the value of early screening and interventions for problem drinking and hazardous alcohol use [
43]. For example, in a study by Archie and colleagues [
18], hazardous alcohol use was found to be significantly lower after 12 months than at baseline after early intervention amongst a sample of first-episode psychosis patients. Another study [
44] indicated that when hazardous alcohol was reduced (after a targeted intervention amongst a sample of psychiatric patients), anxiety and depressive symptoms improved significantly faster than patients without the intervention.
Strengths and limitations
The current paper’s strengths lie in that it is the first paper to our knowledge that has examined the associated factors and clinical outcomes of hazardous alcohol use among a study sample with FEP, as well the relationship with the quality of life domains. While a lot of previous research has often subsumed alcohol use and abuse under “substance use disorders”, this paper builds on current limited research on the prevalence of specifically hazardous alcohol use amongst the FEP population. Furthermore, the paper included a multi-ethnic population of patients with FEP, building on research on existing research in hazardous alcohol use amongst the FEP population in Asia.
The findings reported in this paper should be interpreted in accordance with the study’s limitations. Hazardous alcohol use in this paper was measured with a self-report instrument (the AUDIT scale). This permits social desirability bias with participants possibly under-reporting their alcohol consumption. This would mean that the true prevalence of hazardous alcohol use in the study sample could be higher than reported. However, this was minimised by using a self-report method of data collection (as opposed to needing to interact with an interviewer). Additionally, we used a cut-off of 8 points on the AUDIT scale, for both men and women, for identification of hazardous alcohol use. This cut-off point was deliberately chosen to make a direct comparison with Tay and colleague’s study [
22] which also assessed hazardous alcohol amongst inpatients in a general hospital in the same country (Singapore). However, a lower cut-off point (6 points or more) has been suggested for women in some studies to be more appropriate [
45,
46]. This would mean that the true prevalence of hazardous alcohol use in the study would likely be higher. Participants might also have difficulty remembering the number of units of alcohol they had consumed due to memory impairments in forming new long term memories, particularly after consuming large amounts of alcohol and if consumed rapidly [
47]. This might also have influenced the prevalence of hazardous alcohol use in the study sample. The number of hazardous drinkers (
n = 36) found in the sample is small and the results from the multiple logistic and linear regression analyses must be interpreted with caution. Lastly, due to the cross-sectional nature of the study design, temporal relationships cannot be drawn about comorbid hazardous alcohol use and the onset FEP.