Bea Mitchell has obsessive-compulsive disorder and experiences debilitating intrusive thoughts about her partner and their relationship. As she wants people to understand OCD better, she has written here about how it led to her recent decision to get healthy:

I don't care about my health because I'm not far off 30, or because I want to be fit, toned or thin. I care about my health because if I don't, my OCD runs wild, causing extreme anxiety.

Healthy living is something I've never really aspired to. The sheer bliss that drinking, eating, smoking - and the rest - brings me makes it well worth sacrificing a “bikini body".

And I've always been almost entirely sedentary because I omitted “go to the gym" from my pursuit of pleasure to-do list. Unfortunately I recently had a breakdown, brought on by my OCD intrusive thoughts. I couldn't get out of bed, let alone do any work. After years of successfully self-medicating and having a hedonistic riot, I had to sort myself out.

As soon as I worked out what was going on, I quickly (and begrudgingly) cut down on anything that could potentially make me anxious or paranoid. I've been very gradually working on improving my health since then. Here are my 4 tips for becoming healthy to combat anxiety:

1) Alcohol is a depressant

The more I drink, the lower I feel. The lower I feel, the more likely I am to have intrusive thoughts, and my anxiety goes through the roof. Alcohol interferes with the chemical balance of our brains and our serotonin levels, affecting our thoughts and feelings. My best days are those that follow a day of low- or no-alcohol consumption. When I've had a few too many, the next day can be a nightmarish haze of angst and despair.

2) Drugs are best avoided

They can affect serotonin levels too and meddle with the chemicals in the brain, as a result affecting the messages those chemicals are attempting to send. Stimulants, including caffeine, increase brain activity through the central nervous system, and can cause nervousness, mood swings and anxiety. Psychoactive drugs, including alcohol, can heighten some emotions and quell others.

3) Even coffee affects me

Cutting down on caffeine, much to my surprise, appears to have worked wonders. The National Institute of Mental Health advises people with anxiety disorders to avoid caffeine as it increases heart and breathing rate, accelerating your body's stress response. If you're already stressed, it's like rubbing salt in the wound.

4) And exercise helps too

As an absolute last resort, I actually got up off the sofa and tried exercising. And it really helped. Exercise motivates feel-good endorphins and lessens the stress hormones adrenaline and cortisol. It also increases serotonin levels, raises core body temperature and reduces muscle tension; all of which reduce anxiety.

For years I belligerently refused to believe that a few changes in my physical health would improve my mental health. I'm not holier-than-thou mind; I still drink alcohol and caffeine, I still smoke, and I eat far too much. But I can't indulge like I used to: misery, intrusive thoughts and anxiety simply aren't worth it.

Many people find dealing with anxiety overwhelming. If you want to discuss it with a counsellor therapist.