Before I suffered clinical depression, I thought being “depressed” meant a slow descent into lethargy and low mood. Depression can indeed present in this way. But my own experience was different.

The first thing I discovered is that depression can strike suddenly. At 6 p.m. one evening 12 years ago, I was a 38-year-old mother who had recently given birth to twins. I was also a former London Times journalist throwing a noisy neighborhood party. In short, I was trying to have it all. A few hours later I was suicidal.

I can remember the moment when I knew that I had lost my battle against a terrifying enemy. Our house in tiny Notting Hill, West London, was packed with family, friends, and neighbors for our annual Christmas drinks: There were journalists, lawyers, and writers, as well as Conservative politicians, including many who would go on to run the country. There were also my husband Sebastian’s colleagues; he was then a junior banker at Goldman Sachs.

I had been trying to be the consummate hostess, twirling strangers together as if I was choreographing an elaborate dance. But my mistake was briefly pausing for breath in the kitchen amid the dirty glasses and empty trays. At that moment, it felt as if a trapdoor had opened, and I was falling. It felt as if I was on a plane that was crashing.

This is the second thing I learned about depression: it can present with alarming physical symptoms. Mine included nausea — I kept feeling as if I was about to throw up and couldn’t eat. And I thought I was having a heart attack — my heart was beating so wildly.

Most unpleasant of all my symptoms was an active sense of dread that disaster was about to strike. Something terrible was going to happen and I couldn’t do anything to stop it.

A psychiatrist gave me sleeping pills, which gave me some rest. But upon waking, all the symptoms were back. Soon I was taking antidepressants to address my anxiety, beta-blockers to slow my racing heart, other drugs to reduce my nausea, and sleeping pills at night.

Dr. John Horder, a former president of Britain’s Royal College of General Practitioners, once likened the physical effects of depression to coronary pain. He said that if he had to choose between suffering from renal colic, a heart attack, or an episode of severe depression, he would avoid depression.

A third aspect of depression that I discovered, which psychiatrists naturally don’t tend to share, is how long antidepressants can take to work. Rightly, doctors are in the business of giving us hope that we will recover quickly. The American Psychiatric Association is careful in its wording on its website. “Antidepressants may produce some improvement within the first week or two of use.” My italics: note the “may.”

The drugs didn't seem to be making any difference, at least not for the first six weeks. The problem was that those six weeks were the longest of my life. During that time I felt suicidal and my only comfort came from prayer and poetry, providing what Robert Frost called “a momentary stay against confusion.”

I’m not sure what else you can turn to when you dream of ending your life and the drugs don’t seem to be working. My favorite line from Corinthians said, “My strength is made perfect in weakness.” It somehow made sense of the horror. I would emerge stronger. I would repeat the phrase, mantra like. It was the first stirring of positive will.

The fourth thing I learned, and again it’s something that psychiatrists quite naturally don’t tend to emphasize, is the unpleasant side effects that can come with antidepressants. Over the years, I’ve taken different types of antidepressants, including the more old-fashioned tricyclics or TCAS, as well as the newer generation of pills, known as SSRIs, or selective serotonin reuptake inhibitors. All of them have had side effects.

These have included weight gain: I’m 1 meter, 52 centimeters tall (about 4-foot-10) and normally weigh around 50 kilograms (114 pounds). The drugs made my body balloon and I put on around 8 kg (17 pounds). They also made me feel nauseous. Some made my tongue furred, a desert behind my teeth. My lips cracked. Sometimes I felt as if I was dressed in lead. Yes, the drugs worked in the sense that the crashing sensation abated, but now I was like an insect trapped in amber. As for any romantic life...

The fifth thing I discovered, and it’s yet another aspect of the illness that psychiatrists tend to be quiet about, is how hard it can be to come off antidepressants. After my second depressive episode, it took me around 18 months, during which time I thought of nothing else.

What I learned is that antidepressants are serious drugs for a serious condition, and ideally should be used for short periods. They should not be marketed for life's dips, what Freud called our “ordinary human unhappiness.” Doctors need to make this clearer.

The sixth thing I learned was that I needed to radically change my life to reduce my chances of being ill again. Therapy taught me that I had to reassess what I understood to be the definition of success. I had to face the uncomfortable truth that trying to “have it all” — being the wife, mother, career girl, and hostess — led to “having a breakdown.”

My descent into depression is a cautionary tale for anyone who tries to juggle the multiple demands of work, family, and their own need for status and approval above their own emotional wellbeing and health.

Now, I try and lead a good enough life. I watch out for my relentless perfectionism, and have tried to develop a more compassionate inner voice, less judging of myself and others.

My own toolbox of strategies to beat what Winston Churchill called the “Black Dog” wields the healing powers of poetry, which I first discovered when acutely unwell. It's free, has no side effects, roots me in the present, stops me from worrying about the future or regretting the past, and provides a positive narrative within my head.

Exercise is crucial, too, as well as diet. I'm now an advocate of B vitamins (good sources include tuna, lentils, eggs, pulses, leafy green vegetables), a deficiency of which can lead to “deep depression.” Learning to practice mindfulness, too, helps to lower stress levels — non-judgmentally focusing on what one is experiencing in the moment.

My other failsafe is involving myself in noble deeds, what George Eliot called “unhistoric acts” of kindness. I always feel better after one of the poetry workshops I run at our local prison or after volunteering for mental health charities.

Since I wrote about what happened to me, I’ve realized I’m not alone. I’ve received feedback from hundreds of others whose experiences of depression were similar.

My hope in sharing what I’ve learned is that we can all be more open about the different ways depression can affect people. It’s an illness that can strike suddenly, with horrid physical symptoms, and treatment with medication is not always without side effects or problems.

Moreover, a privileged life doesn’t mean a privileged health, and there can be a high cost to the multiple demands that many women in particular now face. Only with a more open and realistic discussion of this illness can we reduce stigma and explore new cures — such as skipping Christmas parties.

Rachel Kelly, a former London Times journalist, is the author of Black Rainbow: How Words Healed Me, My Journey Through Depression (Quercus USA). Visit or follow @RachelKellyNet on Twitter to learn more.