This study found that most students aged 13 - 14 or in early adolescence tried smoking cigarettes, even for the first time. This study is consistent with the 2014 GYTS results, which found that the most frequent age for Indonesian teenagers first to try cigarettes was between 12 and 13 years old (
3). The frontal lobe develops during early adolescence and is responsible for reasoning and making decisions, leading adolescents to be more inclined to act impulsively and not think rationally, making them more exposed to risky behaviors like smoking (
1).
This study shows that 21.5% of students frequently smoked in the last 30 days. This proportion is higher than the study of Indonesian students aged between 13 and 15 years conducted by GYTS in 2014, which was 1.8% (
6). In contrast to the GYTS study, where early adolescents made up the majority of the sample, the current study's sample consisted primarily of late adolescents (98%), showing that more pupils engaged in smoking behavior (
12). In addition, the sample of this study was also dominated by men (72.8%), in following with the study by Harsanti and Wicaksono on Indonesian students, which found that smoking was more prevalent in males (
13), indicating that the frontal lobe develops more slowly in males. Hence, men tend to act impulsively and not think critically compared to females (
1).
Of the 258 respondents who had smoked, 70.5% tried vaping, which was lower than the research by Putra et al. in Denpasar, who found that 94.7% of Denpasar's teenagers had previously smoked electric cigarettes (
4). This study also found that 8.1% of students frequently vaped within the last 30 days, which is higher than the results of research on American students conducted by YRBS (2017), which found that 3.3% of students frequently vaped (
14). The high prevalence of vaping can be related to adolescent perceptions about e-cigarettes, specifically that e-cigarettes are safer than conventional cigarettes and can help conventional smokers quit smoking, persuading teens with good mental health to prefer e-cigarettes (
4,
15,
16).
This study did not analyze the relationship between cigarette smoking, vaping, and depressive symptoms. However, animal studies have shown that in adolescent mice, the signaling receptor nicotinic acetylcholine (nAChR), which is involved in various neurobiological systems implicated in the pathophysiology of depression (
17), is still changing actively. The functional activity of nAChR in these adolescent mice is higher compared to adult mice. So, nicotine is more likely to cause long-term changes in parts of the brain that are still developing in teenagers (
16).
Long-term use of nicotine can cause decreased synthesis and release of serotonin in the hippocampus area and decreased serotonergic neuron firing in the midbrain raphe nucleus (
18,
19). Serotonin is a neurotransmitter that regulates emotions; it indirectly affects mood through processing emotional information in the brain. In individuals with abnormal serotonin states, negative emotional processing can occur, so low serotonin levels are associated with depression and an increase in one's predisposition to suicide attempts (
18,
20).
This study found that 32.9% of students had depressive symptoms, such as feeling sad or hopeless for two weeks, more than the 21.3% found in a 2007 study of Indonesian students by the global school-based student health survey (GSHS) (
21). While the frequency of depressive symptoms in the form of suicide intents (5.4%) is nearly identical to the results of the 2015 GSHS study (5.14%), the prevalence of creating a suicide plan (6.2%), and attempting suicide (8.2%) is greater than the study results (5.54% and 2.39%) (
22).
Students who smoked cigarettes reported experiencing more depressive symptoms than those who used electronic cigarettes. The proportion was higher for smoking because more respondents had tried smoking rather than vaping. One reason students start vaping is that they used to smoke cigarettes. Therefore, students who vape may have started smoking before or begun vaping while still smoking. In addition, the affordability of cigarettes is higher than that of vaping, and cigarettes are much cheaper. In Indonesia, people, even teenagers, can easily buy cigarettes and vape. The tobacco law is not strictly applied (
23). Affordability, also accessibility affect smoking and vaping behaviors (
24).
Most students who experienced feeling sad or hopeless for two weeks in the last 12 months were frequent smokers, which can be caused by self-medication, where unhappy individuals are encouraged to consume cigarettes to get the acute effects of nicotine. Acute nicotine consumption triggers dopamine release, giving smokers a sense of comfort and thereby eliminating the feeling of sadness until the effect disappears (
7,
24). Murphy et al. state that the effect of removing feelings of dysphoria from nicotine is very strong, to the point that it could encourage someone to start or continue the behavior of smoking (
25).
In this study, we only looked at the emergence of depressive symptoms expressed by students that were not confirmed by expert examination, so it is not yet a diagnosis of depression. However, the symptoms disclosed are the main symptoms of depression, ranging from sadness, and hopelessness to suicidal ideation, and suicide attempts.
Smokers or vapers might experience depressive symptoms. Fergusson et al. in New Zealand reported that depressive symptoms and smoking behavior could be attributed to risk factors such as sex, race, comorbidity with anxiety and alcohol use, association with certain peers, and the experience of bad events in life, especially in childhood. These factors, alone or together, can cause depression symptoms, smoking, and vaping behavior (
26).
This research was conducted in an urban setting in Jakarta, the capital city and busiest area in Indonesia. Regarding social-economy background, the students are from lower middle-class families. As mentioned by Rahim et al., one of the significant predictors of smoking behaviors in urban areas is economic status, in which smokers predominantly come from middle- and low-income families (
27). Further research needs to be done to ascertain the causes of experiencing depressive symptoms, smoking, and vaping behaviors in high school students in Jakarta.
5.1. Conclusions
In conclusion, most students in Jakarta tried smoking cigarettes for the first time during early adolescence (13 - 14 years old). They are more likely to become frequent smokers or vapers. Moreover, those who frequently smoked or vaped experienced more depression than those who rarely smoked. Smoking behavior at a very young age poses a risk to overall health. The findings of this study should serve as a wake-up call for those working to prevent diseases caused by smoking behavior. Factors such as youth characteristics, socioeconomic background, and urban setting may contribute to developing smoking and vaping behaviors or depressive symptoms.