In recent times, the use of substances has become increasingly prevalent among patients presenting with behavioral problems in psychiatric emergency rooms (
18,
19). Recent studies, especially in Western countries, have highlighted a high prevalence of psychiatric disorders among individuals with substance addiction. The diagnosis of substance-induced psychiatric disorders has been included in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM) since 1994 (
20). However, even before that, these disorders were categorized under organic mental disorders (
21).
The prevalence of smoking in the general population of Iranian society has been reported as 14.1% (
22). Nevertheless, this study reported a smoking prevalence of 37.2% among the study population, indicating a higher prevalence of smoking in this group. In Iran, smoking is six times more common in men than in women (
22,
23); nonetheless, in this study, the male-to-female smoking ratio was reported as 3 to 1. This finding suggests that the proportion of female smokers among psychiatric emergency patients is higher than in the general population.
In a similar study conducted in 2008, the prevalence of smoking among individuals attending the psychiatric clinic of the same hospital was reported as 31.8% (
24). This finding suggests that either smoking rates have increased in recent years or that smoking is more common among patients in psychiatric emergency departments compared to outpatient psychiatry clinic.
Regarding a family history of psychiatric disorders revealed that at least one family member had a known psychiatric disorder in 10.2% of the cases. According to the results of WHO’s global surveys on mental health, all psychiatric disorders have a population-attributable risk ratio of 12.4% for disorders among parents of affected individuals (
25).
The most common symptoms observed in patients included self-talk (8.1%), auditory hallucinations (5.9%), incongruous crying (4.7%), incongruous laughter (3.8%), visual hallucinations (2.6%), and other hallucinations (1.9%). It is noteworthy that the final diagnoses for 22.8%, 11.3%, and 8.2% of patients were schizophrenia, substance-induced psychotic disorder, and unspecified psychotic disorder, respectively. Additionally, considering the results of the urine tests and the inherent characteristics of some of the substances used, these symptom patterns can be justified (
26). The psychiatric emergency service has the clinical impression that excessive use of amphetamine or methamphetamine leads to a significant number of patients presenting with symptoms such as paranoia, hallucinations, or formal thought disorders. However, some studies did not demonstrate a clear relationship between these symptoms and substance use (
27). In a study conducted in the emergency department of a general hospital in the same area as the current study, statistically significant differences were observed in visual hallucinations (P = 0.001), auditory hallucinations (P = 0.001), paranoia (P = 0.001), delusions of grandeur (P = 0.035), talkativeness (P = 0.001), suicidal thoughts (P < 0.001), homicidal thoughts (P = 0.001), violence (P > 0.001), and disorientation (P < 0.001) in patients who tested positive for methamphetamine, compared to those who tested negative (
28).
When examining the final diagnoses of patients, the most common diagnosis was bipolar disorder (25.3%), followed by schizophrenia (22.8%). In another study conducted in the outpatient psychiatry clinic of the same hospital, the prevalence of mood disorders was 36.7%; however, schizophrenia and other psychotic disorders accounted for 28.7% (
24). In a study conducted by Breslow et al. in the USA, prevalence of schizophrenia among individuals referred to the psychiatric emergency room was similar to the findings of the present study (
29).
Substance-induced psychotic disorder was the most common clinical diagnosis in the current study's patients with positive urine tests for opium, methadone, and morphine, followed by schizophrenia. Among patients with positive urinary cannabis tests, schizophrenia, and substance-induced psychotic disorder were two of the most common diagnoses. In a study by Farnia et al. in the west of Iran, amphetamine-induced psychotic disorder was the most prevalent diagnosis (in 40.4% of patients), followed by opiate-induced psychiatric disorders (
30). In a study on diseases associated with drug use conducted by McCabe et al. in Australia, the rate of schizophrenia was reported to be 10.4% among patients, which is lower than the prevalence observed in the present study (
31). The most common diagnosis in the aforementioned study was depression, with 45.8% of the individuals affected. Nevertheless, in the present study, depression was diagnosed in only 7.8% of the patients.
Considering that depression is usually more prevalent among women (
32,
33) and in the study of McCabe et al. More than 50% of the patients were women (
31) and in the present study women constituted only 29.8% of the patients, the results related to the low prevalence of depression can be justified. Of course, it should be noted that due to the limited number of psychiatric emergency beds, these beds are often allocated to patients exhibiting aggressive behavior (comprising more than 50% of cases in the current study), and depressed patients are usually admitted to non-emergency departments.
In the substance use screening of patients referred to the psychiatric emergency room in the current study, the highest positive rate was related to opioids (including methadone), accounting for 27.4% of the cases. This finding is consistent with previous research, indicating that opioids are the most commonly used substances in Iran (
24,
34). A study conducted in western Iran by Farnia et al. reported that 80.5%, 15.8%, and 3.1% of hospitalized cases used amphetamines, opioids, and cannabis, respectively (
30). In Ley et al.’s study in England, only 3% of cases tested positive for opioids; nevertheless, the prevalence of cannabis consumption was 14% (
35). However, in the present study, only 3.5% of cases had a positive cannabis test. Tijdink’s study in the Netherlands reported a 22% positive urine test rate for cannabis, with a 10% positive test rate for opioids, which is closer to the findings in the present study (
36).
The above-mentioned variations can be attributed to differences in the pattern of drug consumption between Iran and the countries in the aforementioned studies. For example, in the Netherlands, marijuana use is not illegal, and its legal status likely contributes to higher usage rates. In studies conducted in Western countries, cannabis consumption among psychiatric emergency room patients has been reported to be as high as 40% (
37). In the general population of Iran, the prevalence of raw opium, opium juice, and heroin consumption has been reported as 69 - 94.6%, 50.1%, and 28 - 43.5%, respectively. This figure for cannabinoid substances has been 13% (
38).
One notable aspect of this study is the high number of positive reports in methamphetamine tests for patients referred to the psychiatric emergency room (14.5%). In some studies, this figure has been reported to be only 1 - 3% (
35). In a study conducted in the same region as the present study, the prevalence of positive methamphetamine tests among 3263 patients referred to the emergency department of a general hospital was 1.2% (
28). Globally, the prevalence of amphetamine use is estimated to be 7%, with dependence affecting 11% of users (
39). However, in Schiller et al.’s study in the United States, 22% of patients referred to the emergency room tested positive for amphetamines (
18). This variation might be due to under-detection in some studies (
35) and could indicate an increase in the consumption of this substance in certain countries. Amphetamine use has become more popular in recent years (
24-
40). North America had the highest rate of amphetamine use, followed by Oceania. Methamphetamine is believed to be one of the most commonly used illicit drugs in Southeast and West Asia, although prevalence estimates are only available for a few countries (
39).
In some studies, it has been demonstrated that amphetamine use can induce acute psychosis in otherwise healthy individuals. However, no significant relationship has been identified between the blood levels of this substance and psychiatric disorders (
41). Previous investigations involving regular amphetamine users have reported a range of 8 - 46% experiencing substance-induced psychotic disorders (
42-
48). In the current study, the most common diagnosis among methamphetamine users was methamphetamine-induced psychotic disorder (39.8%). The psychotic symptoms resulting from methamphetamine use often resemble those seen in schizophrenia. However, methamphetamine-induced psychotic disorder typically resolves following detoxification from the drug. It is worth noting that full recovery might not always be achieved after methamphetamine detoxification (
49). A study conducted in Japan by Akiyama revealed that amphetamine-induced mental disorders can persist for several years, with recurrences even after apparent recovery (
50). This finding underscores the complexity of managing this issue, given that existing psychosocial interventions, aside from contingency management, have shown limited overall efficacy, and there is no effective pharmacotherapy available to reduce stimulant use (
39).
It is important to highlight that substance-induced psychotic disorder was the most prevalent diagnosis among individuals who had used any substance. Therefore, the high rate of substance abuse among psychiatric patients in the psychiatric emergency department, coupled with the substantial percentage of patients experiencing psychosis, underscores the need for special attention to this matter. One significant barrier in addressing this challenge is the perception of substance use as a manageable health condition, which continues to be hindered by stigma and legal discrimination (
19). Additionally, substance abuse is highly comorbid with other psychiatric disorders. This comorbidity can complicate the course of treatment and recovery for both substance use disorders and other psychiatric conditions and contribute to issues such as violence, spousal abuse, homicide, suicide, and accidents (
19,
51,
52).
One of the strengths of this study was the use of laboratory tests to investigate substance use. However, some experts argue that qualitative urine substance screening might have less impact on clinical management decisions in psychiatric emergency services and provide less additional information than a detailed patient history (
53). The limitations of this study included the possibility of laboratory errors (false positive or false negative test results) and the retrospective nature of the data review.