# Detecting Suicidal Ideations in Online Forums with Textual and Psycholinguistic Features
## 5 Discussion
### Informative Features  
During the feature selection process, we were able to identify the features that had the biggest contribution to suicidal ideation detection. It is worth noting that most LIWC categories are organized hierarchically. LIWC's _linguistic_ category and its subcategories \(i\) and _negate_ are among the most informative features.  
In particular, suicidal texts, on average, contain 4.24% more first-person singular pronouns (LIWC feature _i_) compared to non-suicidal texts. Examples of such pronouns include \"I\", \"me\", \"myself\", and \"my\". This trend is also reflected in TF-IDF features, where features _myself_ and _my_ have higher average values in suicidal texts. This findingaligns with the existing literature [12]. Arguably, individuals with suicidal tendencies use more first-person singular pronouns as they express their psychological distress, as well as in the context of inflicting harm on themselves or ending their lives.  
The suicidal texts also scored higher in the LIWC categories related to negations (e.g., \"no\", \"not\", \"never\", and \"nothing), as well as all-or-none thinking that includes the words \"all\", \"never\", and \"always\". Regarding TF-IDF, this tendency can be observed in features _anymore_, _not_, and _no_. This is consistent with the conclusions of prior research [41]. The dominance of these features in suicidal texts potentially suggests that suicidal individuals exhibit all-or-nothing thinking when they communicate on suicide support forums. All-or-nothing thinking (also known as polarized thinking) is a type of exaggerated negative thought patterns called cognitive distortions [42].  
Another notable pair of LIWC features that are prevalent in suicidal texts are the categories _friend_ and _conflict_ that pertain to social behavior. The _friend_ category includes terms such as \"boyfriend\" and \"girlfriend\", while _conflict_ includes \"fight\" and \"attack\". The similar pattern can be seen in TF-IDF features _friend_ and _family_. The prevalence of these features possibly indicates that suicidal people are discussing relationship issues on Reddit suicide forums. This is quite plausible, as relationship conflict is known to be one of the key suicide risk factors [4].  
As expected, suicidal texts score higher in the _want_ and _death_ LIWC categories and similar TF-IDF features such as _kill_, _end_, _life_, _die_, _want_, and _suicide_. This combination of features appears more frequently, likely because at-risk users express their desire to end their life.  
Interestingly, the non-suicidal posts contain more words related to anxiety. We believe this is because about 33.27% of the non-suicidal class consists of posts from the \(\tau\)/Anxiety subreddit. It is also worth noting that the average LIWC _clout_ score was 16.83% lower in suicidal texts. This score describes the social status, confidence, and sense of power that the person demonstrates in their writing [34]. This suggests that suicidal individuals exhibit more powerlessness compared to their non-suicidal counterparts when communicating online.