Why would anyone choose to be unhappy? It's a tough question to answer, but one all therapists must wrestle with on a daily basis. Let's say someone comes to see me suffering from depression, which can be extremely unpleasant. Life may seem joyless and devoid of pleasure. They will probably be exhausted, unable to summon up the energy to do more than the absolute daily necessities, if that. They may be angry, anxious and in pain a great deal of the time. And their head will be filled with dark thoughts as they focus on all the negatives in their life, real and imagined, while struggling to find a single thing to feel good about. Depression is no fun at all.

So I roll up my sleeves and get to work, helping them climb out of that gloomy, hopeless place; explaining why we get depressed and reassuring them that they can and will get better; getting them to do some of the tiny, practical things (seeing family and friends, giving themselves small treats, taking as much exercise as they can manage) that make a surprisingly big difference to our daily mood; and, crucially, using cognitive-therapy techniques to challenge and change some of the negative, self-attacking thinking that lies at the heart of depression.

Some people respond by working equally hard. They are desperate to get better and stay that way, so they complete the 'homework' I give them after each session, start taking better care of themselves and allow a little of that magic ingredient - compassion - into their lives. And, as all the clinical evidence confirms, these people make rapid and lasting improvements. Not only do they feel better now, but they possess the psychological tools to keep depression at bay and remain healthy in the future.

Others respond differently. They clearly want to get better - otherwise why would they pay me to help and turn up week after week? - but they remain deeply skeptical of the process. They do some assignments, but not others. They don't make any lifestyle changes, taking no exercise and getting too little sleep/rest. And they continue bullying themselves, even though they know (intellectually, at least) that this is what causes and perpetuates their low mood.

In therapeutic terms, this is known as 'resistance' and involves the part of a client's psyche that refuses to get better, however much the rest of them wants to. Stubborn and tick-like, this resistant part refuses to budge. This may seem odd, but it actually makes a great deal of sense. Change can be scary. Even if we are stuck, unhappy, depressed, that is familiar to us. I call it an 'uncomfortable comfort zone'. If we have been depressed, on and off, for years, then low mood is normal. Anything else - even happiness - may seem threatening and strange.

If this rings any bells for you, don't despair. While acknowledging that this resistant part of you exists, the key is to step out of that comfort zone, doing things that seem new and just a little scary. This is an important point - don't try things that take you way out of that zone, or they will be too challenging. For example, if when you're low you find comfort in over-eating sugary foods, giving up refined sugars completely may provoke a great deal of anxiety. Instead, replacing your chocolate fix with dried fruit on one day a week may not be fun, but it's doable.

And remember that however bad things are, there are often two driving forces within you, one seeking growth and change, the other fighting tooth and nail against it. Frustrating though that is, try to treat both parts with equal compassion - because beneath the stubbornness is the small, fearful child we all carry inside us. With time, patience and hard work that part, along with the rest of you, will eventually heal.

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