Abstract Psilocybin is among the most extensively studied psychedelics, with previous research suggesting its potential therapeutic role in suicide prevention. However, the precise mechanisms through which psilocybin may aid in suicide prevention remain unclear. This study thus employed network pharmacology and molecular docking tools to explore the mechanisms by which psilocybin may contribute to suicide prevention. Relevant drug- and disease-related targets were identified. Overlapping drug- and disease-related targets were extracted from the bioinformatics platform and imported into the STRING database to construct a protein-protein interaction (PPI) network. Key targets were selected based on topological parameters derived from network analyses conducted using Cytoscape 3.10.1. These key targets were further analyzed using GO and KEGG enrichment approaches conducted with the DAVID tool. A drug-disease-target-pathway network was subsequently constructed in Cytoscape 3.10.1. Finally, molecular docking analyses were performed to assess psilocybin’s potential to interact with key targets using AutoDock Vina and the PyMOL software. A total of 46 potential targets associated with psilocybin and relevant to suicide treatment were identified, of which 13 were imported into the DAVID tool for enrichment analyses. Network analyses identified four targets—HTR2A, HTR2C, HTR7, and PRKACA—that may serve as therapeutic targets for psilocybin in suicide prevention. Enrichment analysis outcomes suggested that psilocybin may prevent suicide by modulating the serotonergic synapse and calcium signaling pathways. Molecular docking analyses revealed that HTR2A, HTR2C, HTR7, and PRKACA strongly bind to psilocybin. This study provides insights into the molecular mechanisms underlying the potential role of psilocybin in suicide prevention, offering a novel basis for further research. Subject terms: Psychiatric disorders, Schizophrenia Introduction Suicide is a significant public health issue. Globally, suicide is the fourth leading cause of death among young adults and the third leading cause of death in the United States (US) [[34]1]. In 2020, approximately 12.2 million adults in the US reported serious suicidal ideation, with 1.2 million of these individuals attempting suicide [[35]2]. Suicide is more prevalent among individuals with mental illnesses, who face an estimated lifetime risk of suicide of 5–7% [[36]3, [37]4]. Among people with mental disorders, at least 40–50% exhibit suicidal ideation [[38]4], and a strong hereditary association between major depressive disorder (MDD) and suicide has been documented [[39]3]. Depression-related hopelessness increases the risk of suicide [[40]4], and MDD is a leading cause of suicide, with approximately 800,000 deaths by suicide annually [[41]5]. Therefore, preventing suicide is of paramount importance. Studies investigating the molecular pathogenesis of suicidality have found that the brainstems of suicide victims contain lower concentrations of serotonin (5-HT) and/or 5-hydroxyindoleacetic acid (5-HIAA) than those of individuals who have not committed suicide [[42]6]. Functional alterations in the serotonergic system are independently associated with MDD and suicidal behavior [[43]6]. In addition, neurobiological studies have documented a link between suicide and the dysfunction of the serotonin system [[44]7, [45]8]. Antidepressants have been shown to reduce suicidal ideation in individuals with both comorbid depression and schizophrenia [[46]9], and 5-HT agonists are commonly used to treat and prevent suicidal behavior [[47]7]. However, medications targeting 5-HT receptors that are widely used in clinical practice are associated with slow onset, limited efficacy, and a high frequency of adverse events. Although clozapine, lithium, and ketamine have been demonstrated to prevent suicide in some studies [[48]10, [49]11], their clinical usage is limited owing to their considerable adverse effects, including cardiac arrest, agranulocytosis, addiction, abnormal thyroid function, and impaired kidney function. Therefore, there is a critical need to identify or develop novel medications to prevent suicide [[50]7, [51]11, [52]12]. Previous research has suggested that traditional psychedelics may hold potential for suicide prevention [[53]13, [54]14]. However, the pharmacological properties and effects of psychedelics are complex and can vary significantly across different compounds [[55]15]. The 5-HT2A receptor is an important target associated with the activity of psychedelic substances, but current evidence makes it challenging to determine whether these effects are mediated exclusively through this receptor or result from interactions between multiple receptors [[56]16–[57]19]. Additional research is necessary to understand the precise pharmacological mechanisms of psychedelics, particularly in the case of psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine), which is a hallucinogen that is predominantly present in mushrooms [[58]19]. Psilocybin has been shown to increase extracellular concentrations of glutamate, serotonin, dopamine, and GABA in the frontal cortex [[59]20]. Pharmacological evidence suggests that psilocybin plays a role in anxiety, depression, addiction, suicidal behaviors, and dietary disorders [[60]20]. The U.S. Food and Drug Administration (FDA) has classified psilocybin as a “breakthrough therapy” for treatment-resistant depression [[61]21, [62]22], and this psychedelic has been shown to produce rapid, long-lasting antidepressant effects [[63]18, [64]23, [65]24]. It elicits changes in mood, cognition, and behavior, leading to long-term positive psychological outcomes [[66]25]. Research has shown that the combination of psilocybin and psychotherapy maximizes efficacy and that one or more doses of the drug exhibit superior antidepressant effects compared to the daily administration of other antidepressants [[67]23, [68]24]. In addition, psychedelics enhance prefrontal synaptic plasticity [[69]26], which plays a crucial role in alleviating and preventing depressive symptoms. Based on a limited number of studies, psilocybin may also help prevent suicide [[70]20, [71]27]. In summary, this study primarily examined psilocybin and investigated its possible targets and molecular mechanisms in suicide prevention using network pharmacology and molecular docking approaches. The aim of this study was to provide direction for future fundamental research in order to lessen the harm caused by suicide. A flowchart of this study is shown in Fig. [72]1. Fig. 1. [73]Fig. 1 [74]Open in a new tab Flowchart for the network pharmacology-based analysis of the mechanisms through which psilocybin can help prevent suicide. Materials and methods The current analysis does not require ethical approval, because our analysis only collects uploaded data information from the public database search. There are no human participants in this article and informed consent is not required. Prediction of potential psilocybin-related targets The Canonical Simplified Molecular Input Line Entry System (SMILES) for psilocybin or corresponding SDF files were downloaded from PubChem ([75]https://pubchem.ncbi.nlm.nih.gov/) [[76]28]. In order to systematically identify all relevant targets of psilocybin as we searched for “Psilocybin” in six databases: the PharmMapper [[77]29] database, the SwissTargetPrediction ([78]http://swisstargetprediction.ch/) [[79]30] database, the SuperPred ([80]https://prediction.charite.de/) [[81]31] database, the GeneCards ([82]https://www.genecards.org/) [[83]32] database, the SEA ([84]https://sea.bkslab.org/) [[85]33] database, and the STITCH ([86]http://stitch.embl.de/) [[87]34] database. The species was set to Homo sapiens during this screening process, and a standard target filter Z-score ≥ 2 was applied for the PharmMapper database. Standard target filtering in the SwissTargetPrediction database was set to > 0. In the SuperPred database, known strong binders and predicted targets were selected, and any duplicate entries were eliminated. Non-protein-coding genes from the GeneCards database were excluded. A MaxTC > 1 was selected as the standard target filter when using the SEA database. Using the UniProt database, all retrieved targets were converted into gene symbols ([88]https://www.uniprot.org/) [[89]35]. Identification of potential suicide-related targets The keyword “suicide” was used to search the GeneCards ([90]https://www.genecards.org/) [[91]32], DisGeNET ([92]https://www.disgenet.org/home/) [[93]36], and TTD ([94]https://db.idrblab.net/ttd/) [[95]37] databases, setting the species to Homo sapiens. Duplicate targets were excluded. Screening of common targets associated with psilocybin and suicide We imported the above-obtained targets related to suicide and psilocybin into an online bioinformatics platform ([96]http://www.bioinformatics.com.cn/) [[97]38], which was used to identify common targets related to diseases and drugs that may elucidate the mechanisms of psilocybin in suicide prevention. These targets were saved for further analysis. A Venn diagram was created to show the overlapping targets of psilocybin and suicide. Protein-protein interaction (PPI) network construction and core target selection The common targets were imported into the STRING ([98]https://cn.string-db.org/) [[99]39] database for PPI network construction, setting the species to Homo sapiens, the protein interaction score threshold to a high confidence level of 0.4, and hiding all disconnected nodes in the network. For the network visualization, a tsv file containing the PPI data was obtained and imported into Cytoscape 3.10.1 [[100]40]. The primary targets in the CytoNCA plug-in were identified according to the topological parameters closeness centrality (CC), betweenness centrality (BC), and degree centrality (DC). The median values were chosen as cut-off values [[101]41]. CC denotes a given node’s capacity to transmit information or affect other nodes reasonably rapidly. BC assesses the significance of nodes as “intermediaries” in the network. Degree centrality measure the number of edges to which nodes are directly connected. Finally, the key targets were visualized for follow-up studies. GO and KEGG enrichment analyses of core targets The identified key targets were imported into the DAVID ([102]https://david.ncifcrf.gov/) [[103]42] online tool to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. GO enrichment analysis included the assessment of biological processes (BP), cellular components (CC), and molecular functions (MF). KEGG enrichment analysis primarily entailed the assessment of signal transduction pathways. p < 0.05 was the threshold of significance for these analyses. The top 10 items in each category were obtained, and the resultant data were imported into the bioinformatics ([104]http://www.bioinformatics.com.cn/) [[105]43] tool to generate GO and KEGG enrichment analysis bubble diagrams. Using the KEGG online tool ([106]https://www.genome.jp/kegg/), we additionally prepared KEGG signaling pathway maps corresponding to the pathways through which psilocybin was considered most likely to help prevent suicide. Drug-disease-target-pathway network construction Data related to psilocybin, suicide, signaling pathways, and key targets were imported into Cytoscape 3.10.1 for visualization in order to construct a drug-disease-target-pathway network diagram to further investigate the potential mechanisms by which psilocybin may contribute to suicide prevention. Molecular docking In order to evaluate the binding affinity of psilocybin and its key targets, we used AutoDock Vina ([107]https://autodocksuite.scripps.edu/adt/) to examine the results of molecular docking analyses. The RCSB PDB ([108]https://www.rcsb.org/) [[109]44] protein database served as the source of the crystal structures for the key targets included in these analyses. The PyMOL software ([110]https://pymol.org/2/) was used to eliminate water molecules and small molecules. Then, hydrogens were added to these proteins, Gasteiger partial charge computation was performed, and atom type was established using AutoDock Vina, saving the result in the PDBQT format. Next, the 2D structure of psilocybin was acquired from the PubChem database ([111]https://pubchem.ncbi.nlm.nih.gov/) [[112]28]. By using Chem3D ([113]https://library.bath.ac.uk/chemistry-software/chem3d), energy minimization was performed for psilocybin, and its 3D structure was transferred. Then, small molecules were selected at the root, torsion was selected, and files were saved in the PDBQT format. Finally, we defined the docking range of the core targets and psilocybin and performed molecular docking. To visualize the optimal docking outcomes, we utilized PyMOL and Discovery Studio ([114]https://discover.3ds.com/discovery-studio-visualizer) to assess the minimal binding energy for each docking result. Results Targets associated with psilocybin and suicide After removing duplicates and consolidating data from the PharmMapper, SwissTargetPrediction, SuperPred, GeneCards, STITCH, and SEA databases, 117 psilocybin-related targets were identified. A total of 2185 suicide-related targets were additionally retrieved from the DisGeNET, TTD, and GeneCards databases. Overlapping target acquisition The suicide-related and psilocybin-related targets identified were imported into the bioinformatics online tool. In total, 55 intersecting targets were identified. These potential targets of psilocybin related to the prevention of suicide were presented using a Venn diagram (Fig. [115]2A). Fig. 2. Targets of psilocybin and suicide. [116]Fig. 2 [117]Open in a new tab A A Venn diagram representing the common targets overlapping between psilocybin and suicide. B The established PPI network containing the overlapping targets from (A). C, D An overview of the topological screening analysis of the PPI network. Thirteen essential targets were obtained after 46 intersecting targets were filtered using degree centrality (DC), betweenness centrality (BC), and closeness centrality (CC). PPI network construction and key target acquisition These 55 intersecting targets were subsequently uploaded to the STRING online database for PPI network construction (Fig. [118]2B). After eliminating all disconnected nodes and edges from the network, 46 targets were imported into Cytoscape 10.1 for topological analyses performed using the CytoNCA plug-in. The network consisted of 143 edges and 46 nodes. By screening the median DC, BC, and CC values, 13 key targets were selected (Fig. [119]2C, D). These included proto-oncogene tyrosine-protein kinase SRC (SRC), 5-hydroxytryptamine receptor 2 A (HTR2A), 5-hydroxytryptamine receptor 1 A (HTR1A), sodium-dependent serotonin transporter (SLC6A4), 5-hydroxytryptamine receptor 2 C (HTR2C), potassium voltage-gated channel subfamily H member 2 (KCNH2), cytochrome P450 3A4 (CYP3A4), 5-hydroxytryptamine receptor 7 (HTR7), cytochrome P450 2C9 (CYP2C9), nuclear factor erythroid 2-related factor 2 (NFE2L2), integrin beta-1 (ITGB1), cAMP-dependent protein kinase catalytic subunit alpha (PRKACA), and C-X-C chemokine receptor type 4 (CXCR4). Details regarding these key targets, which were predicted to play a critical role in this therapeutic context, are presented in Table [120]1. Table 1. Detailed information on the 13 core targets. Gene Target name Degree Betweenness Closeness SRC Proto-oncogene tyrosine-protein kinase Src 17 434.37 0.51 HTR2A 5-hydroxytryptamine receptor 2A 16 126.46 0.50 HTR1A 5-hydroxytryptamine receptor 1A 16 235.59 0.49 SLC6A4 Sodium-dependent serotonin transporter 15 119.56 0.45 HTR2C 5-hydroxytryptamine receptor 2C 13 58.04 0.45 KCNH2 Potassium voltage-gated channel subfamily H member 2 13 227.44 0.48 CYP3A4 Cytochrome P450 3A4 12 340.03 0.51 HTR7 5-hydroxytryptamine receptor 7 9 35.03 0.44 CYP2C9 Cytochrome P450 2C9 7 77.80 0.45 NFE2L2 Nuclear factor erythroid 2-related factor 2 6 217.88 0.43 ITGB1 Integrin beta-1 6 95.67 0.44 PRKACA cAMP-dependent protein kinase catalytic subunit alpha 5 165.20 0.43 CXCR4 C-X-C chemokine receptor type 4 5 46.10 0.42 [121]Open in a new tab GO enrichment and KEGG pathway analysis Key targets were submitted for GO and KEGG enrichment analysis using the DAVID online database. A total of 42 biological processes (BP), 19 molecular functions (MF), 21 cellular components (CC), and 21 KEGG signaling pathways were found to be enriched for these targets. The main pathways enriched BP terms included the following: the G-protein-coupled receptor signaling pathway, coupled to the cyclic nucleotide second messenger; the G-protein-coupled serotonin receptor signaling pathway, chemical synaptic transmission, cellular response to xenobiotic stimulus, viral entry into the host cell, positive regulation of the phosphatidylinositol biosynthetic process, the phospholipase C-activating serotonin receptor signaling pathway, the serotonin receptor signaling pathway, the monoterpenoid metabolic process, and positive regulation of the ERK1 and ERK2 cascade. The most enriched MF terms included the following: serotonin binding, G-protein-coupled serotonin receptor activity, neurotransmitter receptor activity, ubiquitin protein ligase binding, virus receptor activity, 1-(4-iodo-2,5-dimethoxyphenyl) propan-2-amine binding, Gq/11-coupled serotonin receptor activity, caffeine oxidase activity, heme binding, and integrin binding. The core terms of CC included the following: plasma membrane, an integral component of the plasma membrane, glutamatergic synapse, dendrite, G-protein-coupled serotonin receptor complex, synapse, perinuclear region of the cytoplasm, synaptic membrane, and focal adhesion. For a visual overview of the top 10 items in each of these three categories, see Fig. [122]3A. Fig. 3. GO and KEGG pathway enrichment analyses. [123]Fig. 3 [124]Open in a new tab A GO enrichment analysis results showing the top 10 functions. B KEGG pathway enrichment analysis results showing the top 10 pathways. C The overlapping targets associated with the serotonergic synapse and calcium signaling pathway were selected as the top four core targets. D A network illustrating the interactions between drugs, diseases, and pathways. The green and red octagons represent drugs and diseases, respectively. Purple “V” shapes denote pathways, while dark purple “V” shapes indicate key pathways. Yellow and orange hexagons denote the targets, with yellow representing the four core targets. The results of the top 10 KEGG enrichment analyses suggested that the serotonergic synaptic and calcium signaling pathways may play a critical role in suicide prevention through psilocybin (Fig. [125]3B). Targets associated with the serotonergic synapse and calcium signaling pathways were imported into the bioinformatics tool to obtain overlapping targets that were regarded as key targets, including HTR2A, HTR2C, HTR7, and PRKACA (Fig. [126]3C). The significant signaling pathway maps are shown in Fig. [127]4A, B. Fig. 4. Distribution of common targets in the main signaling pathways. [128]Fig. 4 [129]Open in a new tab A, B Network maps of the serotonergic synapse pathway (A) and the calcium signaling pathway (B). Red parks represent potential targets of psilocybin related to its ability to help prevent suicide. Drug-disease-core target-pathway network construction To establish a drug-disease-target-pathway network, the key targets, psilocybin, suicide, and the signaling pathways identified above were categorized and imported into Cytoscape 3.10.1 (Fig. [130]3D). Focusing on the top 10 signaling pathways, 2 core targets were not enriched, while the remaining 11 targets were used to construct the drug-disease-target-pathway. In Fig. [131]3D, the green octagon represents psilocybin, the red octagon represents suicide, the rectangles represent key targets, and the “V” shapes represent the signaling pathways. Molecular docking The overlapping targets associated with the serotonergic synapse and calcium signaling pathways were considered as potential key candidate targets associated with the prevention of suicide by psilocybin, including HTR2A (PDB ID: 7WC4), HTR2C (PDB ID: 8DPF), HTR7 (PDB ID: 7XTC), and PRKACA (PDB ID: 7Y1G). These targets were used to conduct molecular docking analyses focused on their ability to interact with psilocybin (Table [132]2). Generally speaking, binding activity is considered good if it is less than −7.0 kcal/mol, with the conformation exhibiting greater stability [[133]45]. The docking scores of psilocybin were less than −7.0 kcal/mol for all four primary targets. The lowest binding energy level of −7.5 kcal/mol was observed for docking between psilocybin and PRKACA. The results of these receptor-ligand docking interactions are presented in Fig. [134]5A–D. Table 2. Details regarding molecular docking interactions between psilocybin and target proteins. Molecular name Targets PDB ID Residue involved in H bonding H-bond length (A) Binding energy (kcal/Mol) Psilocybin HTR2A 7WC4 SER-159; ASN-343; ASP-155 3.1; 3.8; 3.5 −7.4 Psilocybin HTR2C 8DPF ASN-166; HIS-162 3.3; 3.4 −7.0 Psilocybin HTR7 7XTC ARG-314; TRP-281; ASN-230; GLN-236; LYS-233; THR-104; ARG-232; ARG-232 3.2; 3.2; 3.0; 3.1; 3.0; 3.3; 3.5; 3.6 −7.3 Psilocybin PRKACA 7Y1G TRH-183; TRH-183; LYS-72 2.7; 3.1; 3.2 −7.5 [135]Open in a new tab Fig. 5. Molecular docking of psilocybin with core targets. [136]Fig. 5 [137]Open in a new tab A–D Molecular docking analyses of the interaction between psilocybin and (A) 7WC4, (B) 8DPF, (C) 7XTC, and (D) 7Y1G (encoded by HTR2A, HTR2C, HRT7, and PRKACA, respectively). Discussion Suicide represents a persistent and widespread clinical challenge characterized by complex pathological mechanisms. Mental illness constitutes one of the most significant risk factors for suicidality. While suicide is particularly common among individuals diagnosed with depression [[138]46], conventional antidepressant therapies employed to address suicidality fail to generate the desired therapeutic effect in the majority of individuals. There is thus an urgent need for the discovery of novel pharmacological agents to prevent suicide. Psilocybin has shown efficacy in treating a range of mental illnesses, most notably major depression [[139]15, [140]18, [141]47]. Furthermore, previous studies have shown that psilocybin treatment may reduce suicidal ideation, suicide attempts, and suicidal behaviors [[142]13, [143]20, [144]48, [145]49]. It is likely that in silico techniques will play an increasingly pivotal role in advancing drug discovery and development efforts. Previous studies have successfully implemented molecular dynamics simulations to elucidate the crystal structure of an LSD-bound human 5-HT2A receptor [[146]50]. In this study, we employed a combination of computational biology methods, including molecular docking and network pharmacology, to explore the molecular processes through which psilocybin may aid in suicide prevention. Collectively, our results provide a basis for subsequent target identification via accurate computer-based simulations while also establishing a scientific foundation for ensuing clinical applicability. The GO analysis conducted in this study revealed that the G-protein-coupled receptor signaling pathway, the cyclic nucleotide second messenger, the plasma membrane, serotonin binding, and G-protein-coupled serotonin receptor activity may be critically important in the treatment of suicide. Most serotonin receptors exhibit physiologically significant affinity for psilocybin and associated activity [[147]51]. The majority of serotonin receptors are G-protein-coupled, and G-protein-coupled receptors, or serotonin receptors, may play an important role in psilocybin’s ability to prevent suicide. Serotonin is a monoamine neurotransmitter and an important target for numerous physiological regulatory factors, including hormones, neurotrophic factors, and transcriptional regulators. Once released from the presynaptic axon, serotonin binds to its cognate receptors. It also has a significant impact on the regulation of other brain processes, including sensory processing, cognitive control, emotional regulation, learning, and memory. Seven serotonin receptor subfamilies have been identified, including the only ionic receptor, 5-HT3, as well as the G protein-coupled 5-HT receptor, the 5-HT1 (1 A, 1B, 1D, 1E, and 1 F), 5-HT2 (2 A, 2B, and 2 C), 5-HT5 (5 A and 5B), and 5-HT4/6/7 receptors [[148]52]. KEGG enrichment analysis results further revealed that the serotonergic synapse and calcium signaling pathways play a major role in psilocybin-mediated suicide prevention. Abnormalities in the serotonin system are strongly associated with suicide, and a deeper understanding of the mechanisms through which serotonin influences suicide may aid the development of more targeted treatments. Compared to healthy controls, patients with depression and a history of suicide attempts reportedly exhibit lower serotonin transporter binding in the midbrain [[149]53]. Additional studies have found a relationship between suicidal behavior and alterations in the serotonin system [[150]54, [151]55]. Suicide is a significant symptom in individuals with depression, and most currently prescribed antidepressants are selective serotonin reuptake inhibitors (SSRIs). Previous studies have demonstrated the inconsistent efficacy of antidepressants as a means of mitigating suicide risk [[152]56–[153]58]. Therefore, identifying new antidepressants capable of effectively limiting the risk of suicidality is essential. Recent studies have shown that ketamine possesses rapid antidepressant and anti-suicidal effects [[154]59], suggesting that psychedelics may have the potential to treat depression and prevent suicide. A review of previous studies indicated that psychedelic drugs have the potential to considerably lessen the severity of experience avoidance, depression, and suicidal ideation [[155]49]. Psychedelics primarily influence the 5-HT2A receptor, promote neuronal plasticity, and have anti-inflammatory effects at the molecular level [[156]47]. At the neural level, they can decrease efficacy related to the thalamic cortical filtration, facilitate the relaxation of top-down prediction signals, increase sensitivity to bottom-up prediction errors, and activate claustrophobic cortical circuits [[157]47]. At the psychological level, psychedelics also influence psychological states and sensations, which may affect cognition, beliefs, and behavior [[158]47]. Other research has shown that psychedelics primarily alter cortical feedback circuits and the cortical thalamus, which are the locations of serotonin receptor subtypes involved in information processing [[159]17]. Therefore, gaining a deeper understanding of the intrinsic relationship between psychedelics, the serotonin system, and suicide is crucial. Psilocybin is a common psychedelic that offers unique advantages over other psychedelics [[160]51]. In the frontal brain, psilocybin was able to raise extracellular concentrations of glutamate, GABA, serotonin, and dopamine [[161]13]. Classic psychedelic drugs mainly act on the serotonin system, including the 5-HT1A, 5-HT2A, 5-HT2B, and 5-HT2C receptors [[162]17, [163]60]. Previous studies have shown that 5-HT2A and HTR2C are associated with suicide [[164]6]. This finding aligns with the results of our study, which suggests that psilocybin may modulate 5-HT2A and HTR2C to prevent suicide. Some studies suggest that psilocybin may modulate suicide risk by directly stimulating the 5-HT2A receptor, targeting pathways related to inflammation and oxidative stress, rapidly increasing brain plasticity, inhibiting inflammation, and enhancing spirituality, empathy, and cognitive flexibility [[165]20]. However, the results of the present study, which suggest that suicide prevention by psilocybin may also be associated with HTR7 and PRKACA—factors rarely reported in previous studies—provide a new direction for future research. The calcium signaling pathway was identified as an essential regulatory mechanism in the present study. Calcium (Ca^2+), a common second messenger and highly adaptable intracellular signal, is involved in numerous critical physiological processes. An imbalance in Ca^2+ signaling has been linked to certain major human diseases, including heart disease, schizophrenia, bipolar disorder, and Alzheimer’s disease [[166]61]. In addition, Ca^2+ also participates in the serotonergic synapse pathway [[167]62]. The phospholipase C pathway (PLC) is activated by 5-HT receptor signaling, resulting in the production of the second messenger diacylglycerol (DAG) and inositol 1,4,5-triphosphate (IP3). IP3 mobilizes intracellular Ca^2+ stores in the endoplasmic reticulum, thereby activating calcium/calmodulin-dependent kinases such as protein kinase C (PKC), which phosphorylate other proteins that regulate cellular functions. One study identified three calcium channel-related genes that may be linked to suicide [[168]63]. A separate study found that patients with major depression accompanied by suicidal behavior exhibit calcium signaling disorders [[169]64]. Dysregulated calcium signaling, linked to cell death, may therefore be an early pathological and physiological characteristic of MDD with suicidal behavior [[170]64]. Nevertheless, future studies are needed to explore this possibility. A set of core targets, including HTR2A, HTR2C, HTR7, and PRKACA, was identified based on the overlap between the targets associated with these two pathways. The G-protein-coupled HTR2A serotonin receptor also serves as a target for several medications, including psychedelics. Psilocybin binds to 5-HT receptors with high affinity [[171]19]. Animal studies suggest that psilocybin stimulates neuritogenesis, spinogenesis, and synaptogenesis through 5-HT2A receptors [[172]15, [173]26]. Additionally, the psychological flexibility of psychedelics has been linked to their lipophilicity, as greater lipophilicity enables them to cross cell membranes and interact with intracellular 5-HT2A receptors [[174]15, [175]65]. Psilocybin’s subjective effects are correlated with 5-HT2A receptor occupancy in the prefrontal cortex and other cortical regions [[176]17, [177]66]. The brainstems of suicide victims exhibit reduced levels of 5-HT and/or 5-HIAA after death compared to individuals who did not die by suicide [[178]6]. Furthermore, HTR2A variants have been linked to emotional illnesses and suicide attempts [[179]67]. Serotonin agonists play a particularly important role in the prevention and treatment of suicidal behavior [[180]7], especially in HTR2A. HTR2C is a G-protein-coupled receptor that interacts with serotonin. Transcriptomic sequencing has revealed that reduced HTR2C expression is associated with abnormal neuronal activity in the context of MDD with suicidal behavior [[181]64]. The subjective effects of psilocybin in humans can be blocked by ketanserin, which inhibits the 5-HT2C receptor, indirectly supporting its role as a mediator of psilocybin’s effects [[182]17]. HTR7 is one of several serotonin receptors. The 5-HT7 receptor is at least partially agonized by psilocybin [[183]17, [184]68]. PRKACA is the alpha catalytic subunit of a cAMP-dependent protein kinase that phosphorylates a wide range of substrates found in the nucleus and cytoplasm. It also regulates the number of its regulatory subunits in segregated pools by phosphorylating PJA2, which binds and ubiquitinates these subunits, leading to their proteolytic degradation. More importantly, further research is needed to clarify how PRKACA and HTR7 mediate the relationship between psilocybin and suicide. Our molecular docking results indicated that psilocybin exhibited a strong affinity for key suicide-related targets, including HTR2A, HTR2C, HTR7, and PRKACA. Of these four targets, the lowest binding energy (−7.5 kcal/mol) was observed between PRKACA and psilocybin, suggesting this is the most stable combination. This finding provides a foundation for subsequent research focused on PRKACA as a regulator of the relationship between psilocybin and suicide. Psilocybin demonstrates significant potential in treating a wide range of psychiatric disorders. However, its clinical application is limited by the risk of addiction and abuse [[185]69]. Existing studies indicate that psilocybin does not exhibit the same addictive properties as opioids, ketamine or stimulants [[186]23, [187]70]. Conversely, results suggest that psilocybin-assisted psychotherapy can improve addiction to alcohol, cocaine, methamphetamines, and nicotine [[188]71]. The proposed mechanism is that psilocybin acts on the 5-HT2A receptor to induce neuroplasticity or increase anti-inflammatory properties, which may improve addictive behavior [[189]25]. The molecular mechanisms underlying psilocybin-induced addiction and its potential to treat addictive behaviors require further investigation. Currently, the risk of psilocybin abuse remains a challenging issue. Several scholars have evaluated the abuse potential of psilocybin and provided guidance on its clinical use [[190]72]. Therefore, its clinical use should be closely monitored in the future to minimize the risk of abuse. Furthermore, it is essential to gain a deeper understanding of the relationship between addiction circuits and suicide prevention circuits. Addiction circuits activate the brain’s reward system and involve various neurotransmitters (e.g., endorphins, endogenous cannabinoids, acetylcholine) that regulate dopamine release within the limbic system of the midbrain [[191]73]. Brain regions, including the prefrontal cortex, nucleus accumbens, and amygdala, play an essential role in this process [[192]73, [193]74]. Suicidal behavior is linked to brain circuits involved in the regulation of emotional responses, stress, and impulsivity [[194]8]. These circuits include the prefrontal cortex, amygdala, and orbitofrontal cortex, which are all modulated by serotonin (5-HT) [[195]8, [196]75]. Addiction circuits are intrinsically connected to suicide prevention circuits, particularly with regard to emotional regulation [[197]76]. Additionally, abnormalities within these pathways may contribute to both suicidal and addictive behaviors. Several limitations to this study warrant discussion. First, we predicted potential targets through which psilocybin may help prevent suicide using network pharmacology and molecular docking techniques. However, there remain opportunities for further development of these network information-based approaches. While we comprehensively compiled data from existing databases, the accuracy of these databases could still be improved. Moreover, many of our findings have not been reported previously, and the specific mechanisms through which psilocybin functions remain to be fully elucidated or validated in the context of suicide prevention. Further basic research and clinical trials are necessary to confirm these findings, emphasizing the importance of future in-depth research focused on this topic. In clinical applications, the potential risks of addiction and abuse associated with psilocybin must be carefully considered [[198]23, [199]25, [200]71]. Clinicians must closely monitor psilocybin use to mitigate the risk of abuse [[201]72]. Existing research suggests that addiction circuits are inherently connected to suicide prevention circuits [[202]73–[203]76]. Future insights into the interactions between these circuits will enhance our understanding of the mechanisms by which psilocybin prevents suicidal behavior. Conclusion In summary, our study utilized network pharmacology and molecular docking approaches to explore the potential mechanisms through which psilocybin may contribute to suicide prevention. These findings suggest that psilocybin may mitigate the risk of suicidality through synergistic, multi-target, and multi-pathway effects, potentially mediated by binding to HTR2A, HTR2C, HTR7, and PRKACA, and by modulating the serotonergic synapse and calcium signaling pathways in the brain. However, these results are based on computational predictions and require further experimental validation. Future studies, including clinical trials, are essential to confirm the mechanisms and therapeutic potential of psilocybin in suicide prevention. Author contributions YZ contributed to the acquisition and interpretation of data, and drafting the manuscript. LY contributed to the acquisition and interpretation of data. QZ contributed to the acquisition and interpretation of data. CL contributed to the acquisition and interpretation of data. FM contributed to the acquisition and interpretation of data and revised the manuscript critically for important intellectual content. CZ contributed to the conception and design of the work, interpretation of data, drafting the manuscript, revised the manuscript critically for important intellectual content. All authors read and approved the final manuscript. Funding This work was supported by grants from the National Natural Science Foundation of China (Nos. 81871052 and 82171503) to Chuanjun Zhuo. Data availability The data that support the findings of this study are available from the corresponding author. Competing interests The authors declare no competing interests. Footnotes Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. References