His mental instability also began around this time, and increased gradually over the years.

All this exacerbated his mental instability especially during the 3rd series.

Around this time he began to show signs of mental instability and depression.

Perhaps we will even present evidence of a growing mental instability.

The woman, who had a history of mental instability, lived alone.

So now we have money, love, and mental instability all running in your family.

I think there may have been some mental instability on Grandfather's part.

No one could have endured what she had without suffering from serious mental instability.

Would you consider going to a doctor if he developed any mental instability?

A man crying all the time sounds like mental instability to me.