mental health/mental wellbeing
living with or experiencing mental health problems
don't use mental illness, mental health condition
be specific, eg depression, anxiety, low mood
Refer to these Time to change guidelines for more information on writing about mental health.
try to be empowering and speak plainly, eg say 'if it's harder to get around'
refer to the disability language guidelines on page 27 of the Disability Handbook from the National Union of Journalists for more information on appropriate language when talking about disability
these 2 terms are interchangeable