This research examined and compared the prevalence of different types of hallucinations and delusions, as well as high-risk behaviors, among methamphetamine users with or without methamphetamine-induced psychosis. We found that 47% of the studied population had persistent methamphetamine-induced psychosis, which was similar to the findings of Ahmad Hatim’s study (
17). Also, the longitudinal study of Niemi-Pynttari et al. showed that 30% of people with a history of methamphetamine-induced psychosis developed psychotic illnesses (
18), requiring early treatment and follow-up to prevent them from becoming chronic and suggesting that the risk factors related to schizophrenia may increase the likelihood of methamphetamine-induced psychosis; nevertheless, further investigation is needed (
19).
Regarding the history of consuming methamphetamine, there were significant differences between the psychotic and non-psychotic groups in terms of the amount, age of starting, and duration of use. The participants of the psychotic group revealed significantly higher age of starting methamphetamine use, duration of use, and amount of consumption compared to non-psychotic people. Demographic characteristics were not significantly associated with methamphetamine psychosis. Arunogiri et al. also found a relationship between the frequency-intensity of methamphetamine use and psychosis, but no relationship was found between psychosis and socio-demographic factors (
19).
We found no significant correlation between the concurrent use of methamphetamine and other illicit substances and the incidence of methamphetamine psychosis. However, other studies have reported a link between the use of multiple substances and methamphetamine psychosis. These conflicting findings highlight the need for further research to gain a deeper understanding of less-characterized risk factors of psychosis in this population, including family history, childhood traumas or stress, and social support (
19).
The comparison between the psychotic and non-psychotic groups revealed significant differences in the prevalence of psychiatric disorders, suicide attempts, self-harm, and history of intoxication. We noticed that 39.7% of patients with methamphetamine-induced psychosis had a history of at least one psychiatric illness, which was consistent with previous research reporting a prevalence of 41.4% (
20). This observation supports the hypothesis that individuals with underlying psychiatric conditions are more likely to experience methamphetamine-induced psychotic symptoms (
8,
21).
We also observed a significant difference in the prevalence of suicide and self-mutilation behaviors between the psychotic and non-psychotic groups. The high prevalence of these behaviors highlights the need for early interventions to reduce trauma-related injuries and complications in these people. Takahashi et al. reported that 76.1% of methamphetamine users experienced at least one traumatic event during childhood, such as parental death or divorce and psychological abuse, which was significantly related to suicidal attempts and behaviors (
4). Additionally, a previous study affirmed a relationship between childhood traumas and psychotic symptoms (
22). Therefore, addressing childhood traumas may be crucial for preventing suicidal behaviors and reducing the risk of developing psychotic symptoms among methamphetamine users.
The findings of this study revealed that the most frequent types of hallucinations were auditory, visual, tactile, olfactory, and gustatory types, respectively. A study conducted by Zarrabi et al. revealed that auditory hallucinations (51.3%) were the most common symptom in patients with methamphetamine-induced psychosis, followed by visual hallucinations (18.4%) (
23). Similarly, Fasihpour et al. reiterated that auditory (7.3%) and visual (44.1%) hallucinations were the most prevalent types of hallucinations among methamphetamine users (
20), which was consistent with our results.
According to our findings, the frequencies of second-person and third-person auditory hallucinations were 61.2% and 38.8%, respectively. In contrast, Shelly et al., who assessed 33 patients suffering from methamphetamine-induced psychosis, reported a prevalence of 36.4% for second-person and 48.5% for third-person auditory hallucinations (
24). In our study, the highest prevalence was related to second-person psychotic hallucinations with content related to self-harm, suicide, and murder. It is crucial to consider the content of auditory hallucinations, particularly commanding hallucinations that may lead to high-risk behaviors, to prevent high-risk behaviors among methamphetamine consumers.
Moreover, our study revealed that delusions were prevalent in methamphetamine-induced psychosis, with a prevalence of 71%. Among these, persecution (49.4%), grandiosity (30.2%), and reference (27.9%) delusions were the most common types observed.
We noticed that even individuals without persistent methamphetamine-induced psychosis might experience temporary hallucinations or delusions. So, it is crucial to monitor these people for transient psychotic symptoms, as research suggests that stressful situations and frequent methamphetamine use can lead to the recurrence of psychosis (
9). Visual hallucinations, in particular, may indicate the onset of methamphetamine psychosis (
9), and some psychotic symptoms have been linked to violent behavior (
25). Therefore, it is essential for a specialist to accurately evaluate psychotic symptoms in medical settings where individuals seek treatment or are hospitalized with acute symptoms related to methamphetamine use, where targeted therapy based on accurate assessment is of utmost importance. Overall, caution should be taken when generalizing our results to all methamphetamine users in Iran because the drug is often used in combination with opium or other substances. Additionally, our sample consisted of only inpatients, who may not be representative of all methamphetamine users in the country.
This study found that individuals who have not been diagnosed with stable methamphetamine-induced psychosis may experience temporary hallucinations or delusions. As researchers suggest that stressful situations and repeated use of methamphetamine could lead to relapse into psychosis, it is crucial to monitor these transient psychotic symptoms in this population (
9). Visual hallucinations, in particular, may indicate the onset of methamphetamine psychosis (
9), and some psychotic symptoms are linked to violent behavior (
25).
One limitation of this study was that our sample population was confined to compulsory treatment centers, so it might not accurately represent the diverse community of methamphetamine users. This was due to limited access to the general population of methamphetamine users. Additionally, the psychiatric history of patients was solely obtained by self-reporting, which might have impacted the validity of the data collected. Future studies in this field should consider selecting a larger sample size and recruiting people from the community and outpatient treatment centers to obtain more accurate and generalizable information on these patients and their families.
5.1. Conclusions
In general, our findings indicated that methamphetamine users frequently experienced delusions and engaged in high-risk behaviors. The most common types of hallucinations were auditory, visual, tactile, olfactory, and gustatory, and the most frequent delusions were persecution, grandiosity, reference, guilt, control, and jealousy. There was a significant difference between methamphetamine users with psychosis and those without psychosis in terms of duration of use, age of onset, prevalence of psychiatric diseases, suicide attempts, self-harm behaviors, and history of overdose. Given the correlation between methamphetamine use and psychotic symptoms, it is important to carefully evaluate the history of substance use and examine psychotic symptoms among consumers to develop a targeted therapy plan. Identifying individuals with specific psychotic symptoms is crucial for preventing serious complications associated with methamphetamine use. These observations highlight the importance of secondary preventive measures in reducing the harm and psychosis caused by methamphetamine consumption. Future studies should focus on the cause-effect relationship between observed differences in the two groups.