The simple fact is that people who live on the street are more likely to have mental illnesses. PBS has a good factsheet about the knowns and unknowns of homelessness
In this episode of Here Be Monsters, Terry often refers to Manic Depression, a condition that, per the DSM-5, has been reclassified as Bipolar Disorder.
Bipolar Disorder is a mental health condition that is characterized by extreme shifts in mood, energy levels, memory, concentration, sleep, sex drive, appetite and self esteem.
The causes of Bipolar Disorder are unknown, but it's thought to be hereditary.
Bipolar Disorder can disrupt personal and professional relationships, but it is treatable. Therapy, medication, support networks can help mitigate its negative impacts.
Bipolar Disorder often goes undiagnosed, misdiagnosed, or untreated. If you experience symptoms of Bipolar Disorder, or know someone who does, help is available.
More information about Bipolar Disorder from the National Institute of Mental Health
If you're feeling suicidal, please reach out to the National Suicide Prevention Lifeline in the US, at 1-800-273-TALK
For help outside of the US, here is a list of suicide prevention hotlines for almost every country