Amanda Seyfried's obsessive compulsive disorder has improved since she became a mother.

The 'Mama Mia!' star has been on Lexapro - a drug prescribed to manage depression and anxiety - since she was 19 years old and, although she expected her mental health to plummet when she became pregnant, she actually noticed her symptoms eased.

Speaking to ELLE magazine, she said: ''I'm not on a very high dose. There's definitely a wrong and a right drug for each person. It's all about your chemistry.

''Medication is very helpful for OCD. They say it's 30 per cent helpful and the other 70 per cent is your own work. Pharma companies are the devil in a lot of ways, but we need those drugs. It's just how they're being managed [that worries me].

''Who's getting paid to say what? And who's getting paid to give you what? That's my concern: everybody's medicated and they don't need to be. I have friends that are medicated who don't need anything, just some sun ... In my opinion.''

The 32-year-old actress prepared herself for her OCD possibly heightening when she found out she was pregnant - as it can quite often do with the increase of hormones - but she later realised she was so busy with her 14-month-old daughter that she didn't have time to worry.

She explained: ''I prepared myself before I had her by going back to CBT [Cognitive Behavioural Therapy], just to get myself in that frame of mind to notice when my OCD might be getting worse. But it turns out you're way too busy with other things anyway.

''It definitely didn't void it, but it's absolutely gotten quieter.

''You have less time to worry, or to focus or obsess about things you maybe used to, and it's so grounding. It's real. They depend on you completely now.''

And Amanda is grateful that she has her mother Ann on hand to help her with her child.

She said: ''Maybe you'll think I'm an asshole, but my mother is our nanny,' she smiles. 'Not for free. She came out of retirement to live with us and it's amazing. I sleep so well.''