Personality disorders involve significant differences in how one thinks, perceives, feels, and relates to others compared to average people. People with personality disorders often struggle with substance abuse and mental health issues like depression. Chronic substance abuse is commonly linked to mental disorders such as bipolar disorder, anxiety, schizophrenia, and PTSD. A study of 40 individuals with chronic substance abuse or addiction between ages 15-70 found the highest rates of addiction, 40%, were among those aged 26-35. Common issues associated with substance abuse included mood swings, hallucinations, respiratory problems, and relationship difficulties. Left untreated, drug addiction can severely impact one's life through negative stressors and conditions.