Cook's mother reportedly told police her son wasn't taking his schizophrenia medicationCuz he was smoking dope all day long, which caused his schizophrenia in the first place.
https://www.helpguide.org/articles/mental-disorders/schizophrenia-signs-and-symptoms.htm
Early warning signs of schizophrenia
In some people, schizophrenia appears suddenly and without warning. But for most, it comes on slowly, with subtle warning signs and a gradual decline in functioning, long before the first severe episode. Often, friends or family members will know early on that something is wrong, without knowing exactly what.
In this early phase of schizophrenia, you may seem eccentric, unmotivated, emotionless, and reclusive to others. You may start to isolate yourself, begin neglecting your appearance, say peculiar things, and show a general indifference to life. You may abandon hobbies and activities, and your performance at work or school can deteriorate.
The most common early warning signs include:
Depression, social withdrawal
Hostility or suspiciousness, extreme reaction to criticism
Deterioration of personal hygiene
Flat, expressionless gaze
Inability to cry or express joy or inappropriate laughter or crying
Oversleeping or insomnia; forgetful, unable to concentrate
Odd or irrational statements; strange use of words or way of speaking
While these warning signs can result from a number of problems—not just schizophrenia—they are cause for concern. When out-of-the-ordinary behavior is causing problems in your life or the life of a loved one, seek medical advice. If schizophrenia or another mental problem is the cause, getting treatment early will help.