Can suicide/ depression run in the family?

Yes: Mood disorders and suicidal behavior can & do run in families. This does not mean all family members will automatically have difficulty though. There's a great deal you can do to keep yourself healthy -- such as good diet, exercise, rest/sleep, creative outlets, loving friendships, etc. You can also stay away from alcohol and drug abuse, as those can tilt the balance into illness.

Suicide inheritance: Sure. Genetics play a role in major depression & mood disorders.

Sure: Bipolar & depression are often seen across generations, suggesting a genetic basis. But, families also behaviorally "inherit" coping skills & levels of "differentiation" from prior generations. A person w/ mood problems may be attracted to & marry a person w/ mood problems (same level of differentiation), enhancing the chances that their children will have mood probs. Makes it look all genetic!

DEPENDS: Some kinds of depression and proclivities for depression are genetically based. Some have to do with environment - abuse, abandonment, neglect, etc. Sometimes genetics and environment - but almost all can be helped. Anyone depressed or concerned really should get an expert to help them work it out.