$\bullet$ We compared individuals with amphetamine use disorder (AUD) and healthy controls (HC).

$\bullet$ Compared to HC, individuals with AUD reported higher scores for insomnia and depression.

$\bullet$ Compared to HC, individuals with AUD reported lower scores for perceived social support by their families, friends and significant others.

$\bullet$ Older age and higher scores for depression and insomnia predicted individuals with AUD and HC.

Drug use is one of the globally most demanding health issues, trialing a person’s mental health, a person’s social environment, along with the national health system and the public domain [1, 2]. The latest World Drug Report reporting data from 2021 showed that about 457 million people use illicit drugs [2].

Amphetamines, after cannabis and opioids, are the third most commonly used illicit substances worldwide [2]. Amphetamine is a central nervous system (CNS) stimulant used for the treatment of attention-deficit/hyperactivity disorder (ADHD) [3, 4, 5] and narcolepsy [6, 7]. At therapeutic dosages, amphetamine impacts on emotion (e.g., increased mood), cognition (e.g., increased and sustained attention and vigilance; cognitive control), and behavior (e.g., shorter reaction time, fatigue resistance, and increased muscle strength; see [8] for a more thorough overview). For non-medical purposes, amphetamine is used as a club drug at much higher and thus non-therapeutic dosages for its energetic and euphoric effect. In addition, amphetamine is often combined with other substances such as alcohol and downers (i.e., sedatives, hypnotics and narcotics). Individuals taking amphetamine for non-medical use report increased stimulation, alertness, prolonged wakefulness, and more intense perception of external stimuli. On the flip side, adverse effects can be serious and life-threatening. To name just but a few, cardiovascular issues (hypertension, hypotension or tachycardia [9]), gastrointestinal side-effects, appetite loss, dry mouth, excessive grinding of the teeth, nosebleed, tics and weight loss [10], and, most importantly, amphetamine use disorder (AUD). Amphetamine use disorder was virtually solely observed among non-medical amphetamine users self-administered at high doses, and not, when prescribed at therapeutic dosages for ADHD and narcolepsy [10].

According to data from 2015 as published in the World Drug Report 2023 [2], the highest prevalence rates for substance use in Iran were observed for opioids, followed by amphetamine and cannabis. In the present study, we focused exclusively on individuals with amphetamine use disorder (AUD) undergoing medical and psychotherapeutic treatment in an outpatient emergency center.

The present study aimed to compare symptoms of insomnia and depression and dimensions of social support (family; friends; significant others) between individuals with amphetamine use disorders (AUD) and healthy controls (HC), and to identify which predictors were significant to correctly assign participants to their group. Data showed that compared to HC, individuals with AUD reported higher scores for insomnia and depression, and lower scores for social support. From the binary logistic regression model it turned out that higher age, and higher scores for depression and insomnia correctly assigned participants to the study condition with a precision of 97.4%, though, dimensions of social support were excluded from the equation, as they did not reach statistical significance. The present data add to the current scientific knowledge in the following three ways: First, to our understanding, the present data are novel in that we assessed adult Iranians with AUD. Second, from the comparison with healthy adults of the general population it turned out that individuals with AUD suffered also from symptoms of insomnia and depression, and decreased social support. Third, from the binary logistic model we identified age and symptoms of insomnia and depression as robust predictors to correctly assign participants to their specific groups (i.e., AUD vs. HC). The strength of the present study consists in a thorough assessment of the mental health status of adults with ‘pure’ AUD, this is to say: participants with AUD were carefully selected for not reporting further substance use issues and psychiatric issues.

Two hypotheses and one research question were formulated, and each of these is considered now in turn.

With the first hypothesis, we assumed that individuals with AUD would report higher scores for insomnia and depression than HC, and the present data did support this assumption and corroborate previous findings [16, 18, 30, 31, 32, 33, 34, 35, 36, 37]. However, the data expand upon previous findings in that we thoroughly assessed exclusively adults with AUD. Further, the degree of severity of AUD (i.e., following the DSM-5 [40] they met at maximum five criteria for AUD) was such that participants suffered from a mild to moderate AUD; they were not in a state to be hospitalized, but to follow their everyday life as much as possible.

With the second hypothesis, we expected that individuals with AUD would report lower scores for social support, compared to HC. As shown in Table 2, data did support these assumptions. As such, the present data confirmed and replicated previous research [19, 25, 26, 27, 28, 29]. However, a close inspection also revealed that effect sizes were small (ds between 0.22 and 0.42), or in other words: participants with AUD did not perceive their social environment (family, friends, significant others) as that much less supportive, compared to HC. The quality of the data does not allow a deeper understanding of that pattern of results. We speculate that despite their amphetamine-related issues, participants with AUD felt generally well embedded and supported by their social environment. It may also be possible that a sample bias occurred, in that we approached 712 individuals, though only about more than the half (n = 468; 53.84%) agreed to participate at the study. It is conceivable that compared to non-participants with AUD, participants with AUD were particularly motivated to report on their mental health status, and perhaps their overall impression was that their AUD was not impairing their everyday life so much. Last, though highly speculative, we might have assessed adults, who consumed amphetamine for non-medical reasons, and as such, perhaps they felt well accepted above all from their peers during their leisure time activities, such as attending gyms and clubs. Future studies in this field might assess participants’ motivation to use amphetamine regularly.

The research question was, whether and to what extent symptoms of depression, insomnia and social support from the family, peers and significant others, along with age and gender, would predict to assign individuals with AUD and healthy controls correctly to the specific study condition. The answer was that higher age and higher scores for depression and insomnia were the statistically only predictors, while dimensions of social support had to be excluded from the equation, as they did not reach statistical significance. In our opinion, this pattern of results matches well with what has been mentioned above as regards perceived social support: Considering the effect sizes (ds between 0.22 and 0.42 for all dimensions of perceived social support), participants with and without AUD did not substantively differ in the perceived social support. As such, the exclusion of social support as predictor in the binary regression model is coherent with the overall pattern of results.

Despite the novelty of the results, the following four limitations are considered: First, we fully relied on self-reports, and we did not perform any kind of biological toxicological screening (blood or urine samples) to rule out that participants used other substances. Importantly, this statement holds true for both individuals with AUD and HC. Second, by nature, cross-sectional studies do not allow causal relationships. More specifically, based on the cross-sectional nature of the present study, it remains unclear, whether symptoms of insomnia and depression, both of which are associated with cognitive impairments, encouraged a person to use amphetamines to counteract such cognitive deficits, or whether the use of amphetamines, which by nature impairs regular sleep patterns, caused both symptoms of insomnia and depression. By contrast, previous studies were able to identify a more complex and fine-grained bi-directional association between substance use and social support (see for instance [22, 24, 29]). However, we have run a binary logistic regression, which plausibly needs the definition of predictors and dependent variables. To do so, theoretical and previous data guided us to formulate the model. Third, the individual cognitive-emotional processes (e.g., [29]) and attachment styles (e.g., [48] for some suggestions) were not assessed. In our opinion, this would open a particularly important and fruitful research area, and the reasons are as follows: First, cognitive-emotional processes elaborate a person’s view of the world. More specifically, as regards social interactions, three basic processes are observed: (cf. [49, 50, 51, 52]). While an individual might react to constraints, rules and attitudes of a specific social context (reactive interaction), the pattern of personality also evokes distinctive responses from their social environment (evocative interaction). Last, an individual also actively and selectively choses their social environment; or put the other way round: An individual is not only reactive and evocative to their social environment, but an individual also creates their social world (proactive interaction). Such proactive interactions may further shape and impact on the individual’s beliefs, how the social world appears to function (see also [29]). With this in mind, it would have been interesting to investigate, whether and to what extent dimensions of reactive, evocative and proactive behavior were associated with symptoms of depression, insomnia and social support among the present sample of individuals with AUD. More specifically, it would have been interesting to investigate, whether and to what extent their families, friends and significant others rather encouraged or discouraged the non-medical and recreational use of amphetamine. Fourth, we assessed a ‘pure’ sample of individuals with AUD, while the clinical experience shows that individuals consuming amphetamine often consume further substances such as cannabis, cocaine and opioids. In a similar vein, the co-occurrence of personality disorders or schizophrenia spectrum disorder is often observed. As such, it remains unclear, if and to what extent the present pattern of results is transferrable to a larger sample of individuals with AUD. Fifth, a possible confounding variable is the life history strategy [53, 54]. Briefly, the life history theory is a mid-level evolutionary framework to explain a person’s behaviors and outcomes such as mating strategies, risky behaviors, reproductive development, and health as a proxy of immediate resource provision. Typically, a person’s behavior is conceptualized as indicators of individual differences along a fast-slow life history continuum. To make the case in point, an individual adopting a fast strategy (that theoretically is most adaptive under harsh and unpredictable environmental conditions) uses short-term mating tactics, engages in risky behaviors, including the use of stimulants such as amphetamines, is less future oriented, and devotes less time to their offspring [53, 55, 56]. In a further consideration, and from an evolutionary perspective, use of stimulants may reflect personality indicators of a faster life strategy mirrored by lowered self-control, a short-term mating disposition, selfishness, and increased antisocial behavior [53, 57]. Given this, it appears highly conceivable that the assessment of fast vs. slow life history behavior might have helped to further understand the current pattern of amphetamine use. Sixth and last, research at the interface between psychiatry, biology and evolutionary psychology shows that individuals with opioid-, methamphetamine- [58], and amphetamine use disorder [54] had lower 2D:4D-ratios, and thus were most probably exposed prenatally to higher testosterone concentrations. Given this, it would have been interesting to measure participants’ finger lengths, too, to further investigate a possible biological factor for the tendency to use amphetamine.

Compared to healthy controls, adults with amphetamine use disorder reported additional mental health issues such as insomnia and depression, and lower perceived social support. Given that standardized psychotherapeutic interventions for insomnia, depression and social competencies are available, the implementation of such programs might also favorably impact on amphetamine use.

Data might be made available under the following conditions: (1) Whoever requests the data, is an expert in the field and senior researcher. (2) Requests are made via an institutional email-address (thus, no @gmail.com or @gmx.com or similar). (3) Hypotheses are clearly formulated. (4) The expert in the field and the institution confirm and guarantee, that all data are securely stored on a server of the institution, where nobody else has access to. (5) The expert in the field and the institution confirm and guarantee, that data won’t be shared with third parties, even when the third party belongs to the same institution, department or research team.

Conception—NA, DS-B; Design—NA, DS-B; Supervision—NA, DS-B; Materials—NA, DS-B, NS, MK, ZS, ABB, SB, KMD; Data Collection and/or Processing—NA, DS-B, NS, MK, ZS, ABB, SB, KMD; Literature Review—NA, DS-B, NS, MK, ZS, ABB, SB, KMD; Writing—NA, DS-B, NS, MK, ZS, ABB, SB, KMD; Critical Review—NA, DS-B, NS, MK, ZS, ABB, SB, KMD. All authors read and approved the final manuscript. All authors have participated sufficiently in the work and agreed to be accountable for all aspects of the work.

All participants were informed about the aims of the study and the anonymous and secure data handling. Afterwards, participants signed the written informed consent. The Ethics Committee of Kermanshah University of Medical Sciences, Kermanshah, Iran (ethics code: IR.KUMS.REC.1400.186) approved the study, which was performed in accordance with the current version of the Declaration of Helsinki.

The authors gratefully acknowledge the Iran National Science Foundation (INSF) for financial support (Grant No. 97011213 to NA and SB).

The authors declare no conflict of interest.