The study investigated the kind of relationship existing between mental disorders and criminal activities, such as gun violence; while being explicit on the resulting unlawful influence from such conditions. The research used a descriptive design to tabulate quantifiable data using a continuum mathematical formula. Relevant information came from prison authorities and incarcerated inmates concerning their history on the crimes committed, involvement in substance abuse and possible mental disorder diagnosis. SPSS analysis provided outputs necessary for comparing means through the paired t-test. The targeted population was 300 evenly distributed individuals amidst the mental ills from correctional facilities, rehabilitation centers, and psychiatric hospitals; finally, there was a sample size of 20 people (Anderson, 2017). Through generalization, a stereotype effect is put on the mental ills while individuals diagnosed of schizophrenia are prone to violence. Substance abuse indicates a close relationship with psychiatric conditions, and also displays a correlation with criminal activities. It is schizophrenia and alcohol abuse that present a more intimate connection with violent crimes (Hare, & Hart, 2015). The mentally ills have a role of overcoming the influence of their conditions, thus becoming more acceptable as criminals in the society. The study found that mentally ill people have a high prevalence to commit crime and thus showing a great correlation between mental illnesses crimes such as robbery and gun violence.