Risk factors for major depression: alcohol dependence, female > male, prior hx depression, family history depression, recent childbirth, recent stressful event
Risk factors for suicide: prior suicide attempts, male (higher risk of successful completion), depression or other mental illness (though can be an impulsive act), substance use (can increase impulsivity), access to lethal means (e.g. guns)
Symptoms
5 or more symptoms present most days, x> 2w, causing distress or functional impairment
Feeling sad, hopeless, empty; little interest or pleasure in doing things; impaired sleep (too much or too little); weight loss or weight gain: decreased or increased eating; appearing agitated or slowed down; low energy/fatigue; feelings of worthlessness or inappropriate guilt; diminished ability to think or concentrate; thoughts of death, wanting harming self
No other medical condition, substance abuse, psychiatric condition, or other process that can explain the symptoms
PHQ2 screen (+ response to either of following): over past 2w--> little interest or pleasure in doing things; feeling down depressed or hopeless
PHQ9 (often done in f/u to + PHQ2) can help with diagnosis, assess severity, and can be used to gauge response to therapy