To our knowledge, this is the inaugural study to examine the prevalence of psychotic symptoms and associated risk factors in a substantial cohort of adolescents with first-episode MDD. Although the majority of participants received a diagnosis of NPD, 27.3% (44/161) of adolescents with first-episode MDD exhibited psychotic symptoms. Additionally, a strong correlation was observed between the severity of depressive symptoms and Internet addiction symptoms among MDD adolescents with psychotic symptoms. Moreover, individuals manifesting psychotic symptoms are at a higher risk of attempting suicide.
The current study revealed that the prevalence of psychotic symptoms among patients with first-episode MDD was approximately 1.5 times higher than a previous study involving 92 adolescents who had depression and psychotic symptoms [32]. A previous study revealed a 7.5% lower prevalence of psychotic symptoms in adolescents with MDD [33]. However, another prior investigation reported a higher incidence of psychotic symptoms among hospitalized adolescents with MDD (45%) [23]. These findings suggest that individuals diagnosed with MDD exhibit varying rates of comorbidities in relation to psychotic symptoms. Study selection criteria may impact results due to differences in PD definitions, diverse ethnic groups, varied measurement methods for psychiatric traits, and differing clinical characteristics between outpatients and inpatients.
As expected, the depressive symptoms of patients with psychotic symptoms were found to be more severe than those of patients with non-psychotic symptoms, which is consistent with two other studies on psychotic symptoms in patients with first-episode MDD [31, 34]. Daniel et al. have revealed that patients with a history of psychotic depression experience shorter non-psychotic episodes and less severe symptoms, indicating that the presence of psychotic symptoms is indicative of more intense depressive episodes [35]. Additionally, the presence of psychotic symptoms in patients with depression can exacerbate their depressive symptoms [36]. Studies indicate that patients with severe depression accompanied by psychosis exhibit greater dysfunction and a poorer prognosis compared to those without psychotic symptoms, ultimately exacerbating depressive symptoms [37], and potentially leading to more severe episodes of depression.
We have also observed that BMI is a significant risk factor for the manifestation of psychotic symptoms. Toups et al's research has shown that individuals with high BMI are more likely to exhibit atypical features, including psychotic symptoms, which are closely associated [38]. Meanwhile, Liu et al. found that BMI levels serve as a significant predictor of psychiatric symptoms in middle-aged patients with MDD [39]. However, another study has revealed a U-shaped correlation between BMI and the severity of psychiatric symptoms [40]. This discrepancy may be attributed to our focus on first-episode and adolescent patients, which differs from previous research.
Interestingly, individuals exhibiting psychotic symptoms demonstrated a higher prevalence of Internet addiction compared to those without such symptoms. This finding is consistent with a previous study involving 1007 young adults, which revealed that time spent on the Internet and social media addiction were closely associated with psychotic symptoms [41]. Furthermore, another large-scale study conducted among adolescents found a positive correlation between scores for Internet addiction and the presence of psychotic symptoms [42]. We explored the potential factors underlying the close association between psychotic symptoms and Internet addiction symptoms. It is plausible that individuals with psychotic symptoms are more prone to adopting maladaptive coping strategies for stress reduction compared to those without such symptoms [43]. Internet addiction symptoms, often regarded as a negative coping mechanism, may serve as a means of alleviating stress in their lives [44]. In clinical practice, when encountering PD, doctors should not only focus on curing depressive symptoms but also pay attention to concomitant symptoms such as internet addiction.
Our study revealed a significant difference in suicide attempts between the PD and NPD groups, with patients diagnosed with PD exhibiting a higher risk of suicidal behavior. This is consistent with prior research findings, as demonstrated by Pawlak et al's discovery of a close association between suicide attempts and psychiatric symptoms [45], a Spanish study reporting that 21% of patients with psychotic major depression had attempted suicide while 39% had experienced suicidal ideation [46], and Keerthika et al's identification of a positive correlation between psychotic symptoms in hospitalized patients with MDD and suicidal behavior (OR:1.16, P = 0.007) [4]. We posit that the reasons for this phenomenon are multifaceted. Firstly, our study revealed that depressive symptoms were more severe in patients with PD compared to those without, and greater severity of depression was associated with increased incidence of suicide attempts and suicidal behaviors [3]. Secondly, individuals with PD tend to employ maladaptive coping strategies when faced with stressors, and suicide is often viewed as the most extreme manifestation of such negative coping mechanisms. Finally, a study has suggested that there could be common social and genetic risk factors underlying both psychiatric symptoms and suicidal behavior [47]. Although experimental research may differ from real clinical practice, the increasing attention to adolescent depression has brought its detrimental effects on adolescents into focus.
There are obvious limitations in this study. First of all, this cross-sectional study is difficult to explain the causal relationship between psychiatric symptoms and clinical variables in adolescent patients with MDD. Further longitudinal studies are needed to investigate the causal relationship between them. Secondly, although the participants in this study were limited to relatively first-episode adolescents, the sample size was also limited. Furthermore, all adolescents with severe depression included in this study came from a certain area's outpatient department of a general hospital, excluding inpatients. Therefore, our research results cannot be generalized to community patients or outpatients and inpatients throughout the country or other provinces and cities.
To summarize, our findings indicate that approximately 30% of adolescents with MDD exhibit psychotic symptoms, a startling statistic that underscores the importance of monitoring such symptoms in this population. We have observed a significant correlation between participants' psychotic symptoms and their BMI, underscoring the importance of weight management in addressing patients' mental health concerns. Notably, both Internet addiction and suicide are associated with psychotic symptoms in MDD patients, highlighting the need for early identification of negative coping strategies as well as drug therapy and psychological intervention.