According to an analysis of English newspapers, the number of articles stigmatizing mental illness roughly halved between 2008 and 2016, while those challenging the stigma nearly doubled over the same period. And this appears to have a positive impact on everyday experiences of prejudice – people with mental illness now report significantly less discrimination from family, friends and colleagues compared to just a few years ago. Despite this progress, some myths about mental illness are still widely shared, including false claims about the effectiveness of treatments. Here are six of the most common beliefs and the truth behind them.

Mental illness is overdiagnosed

Let’s start with the idea that people confuse everyday anxiety with a clinical disorder. The claim is a favorite of TV personalities and newspaper columnists, who occasionally claim that the increased focus on mental health is reducing people’s self-reliance so that they turn to medical interventions instead of dealing with their life problems. In fact, there is very little hard evidence that overdiagnosis is the serious problem that some claim. Surveys of depression in Western countries, for example, have failed to reveal much of a rise in diagnoses as people jump into “mental health”. “The evidence shows stability,” says Professor Johan “Hans” Ormel of the University of Groningen in the Netherlands. He suggests that doctors are just as likely to miss real cases as they are to misdiagnose someone who is just experiencing transient discomfort.

Time is a healer

In relation to the claim that doctors treat everyday distress, there is the suggestion that many people who believe they are depressed should be more resilient and simply bide their time to heal their afflictions. If they are just suffering temporary grief, after all, then surely the problem should go away on its own? To find out if this was indeed the case, researchers in Australia looked at data from 16 clinical trials in which a control group of patients had been put on a ‘waiting list’ before receiving treatment. They found that only one in eight of these patients went into remission while waiting for treatment, while the rest continued to have symptoms over the three-month period.

Antidepressants don’t work

It is not only the diagnostic process that has inspired medical myths. The treatments used to help patients are often the subject of misinformation. A common belief is that a common class of antidepressants, called SSRIs (selective serotonin reuptake inhibitors), are ineffective and work no better than a placebo. The idea has recently attracted widespread attention after the publication of a paper that raises some serious questions about the proposed mechanism of these pills. The idea that mental anguish can inspire great art certainly shouldn’t be a reason to avoid treatment SSRIs, which include Prozac, are thought to address a “chemical imbalance” in the brain by correcting levels of the neurotransmitter serotonin, which is thought to be involved in mood regulation, among other functions. The recent paper, however, reviewed the evidence to date and concluded that there was no clear link between serotonin levels and depression. But there are many other ways they may help relieve symptoms – by reducing inflammation, which is another potential contributor to depression, for example. Importantly, a recent meta-analysis in the Lancet, taking into account multiple clinical trials, confirmed that SSRIs are effective in relieving depression. Although they don’t work for everyone, they are about 50% more likely to produce a response than placebo pills. In the words of Professor Cathryn Lewis of King’s College London and Professor Andrew M McIntosh of the University of Edinburgh, the clinical benefits are now “beyond reasonable doubt”.

“Happy pills” just numb people’s emotions

Other myths are about side effects. You’ll see a lot of articles, for example, that claim that anti-depressant pills “dull” people’s emotions. There is a seemingly good basis for this idea: many patients report concerns that their medications have reduced the ups and downs of their lives, making feelings numb. Until recently, however, few studies had investigated the causes of emotional blunting, and it now appears that feelings of numbness may be a residual symptom of depression. It makes sense: depression is often accompanied by apathy and an inability to feel pleasure. SSRIs have removed the most intense feelings of hopelessness – but they do not necessarily increase positive emotions and motivation, says Professor Guy Goodwin of the University of Oxford, who conducted the recent study: “The feeling of emotional dullness is real, but it is not caused from the drugs”.

Mental illness makes people more creative

Perhaps the most persistent myth has been the idea that mental pain is a source of artistic genius – from Virginia Woolf to Kanye West. But any evidence supporting a link between creativity and mental illness is extremely weak, says University of Connecticut professor James C Kaufman. “Historiometric” analyses, for example, have demolished the biographies of notable artists. While these studies seem to indicate that mental illness is more prevalent in creative personalities, any post-hoc diagnoses based solely on a text should be treated with great caution. “They’re not super objective,” Kaufman says. “Very few creativity researchers believe there is a strong connection.” And the idea that mental anguish can inspire great art certainly shouldn’t be a reason to avoid treatment for serious conditions, he says.

Schizophrenia cannot be cured

Despite changing attitudes to other mental illnesses, schizophrenia is still hugely stigmatised, says Marjorie Wallace, the founder and chief executive of mental health charity SANE. “Schizophrenia is still a ‘forgotten illness’ because it has been sidelined by all these anti-stigma campaigns, which have emphasized anxiety, depression and stress.” This means most people only have a vague understanding of the condition, despite the lifetime prevalence being around 1.5% in the UK. A big misconception is that schizophrenia is simply “untreatable.” With the right medications and talk therapies, however, 45% of people with schizophrenia go into remission after one or more psychotic episodes, while 35% have mixed patterns of remission and relapse. The belief that there is no chance of recovery can be a source of great despair for people diagnosed with the disease and their families. (Activist and filmmaker Jonny Benjamin famously described the diagnosis as feeling like a life sentence.) In general, earlier interventions are more effective. But chronic under-resources in health services mean many people with schizophrenia fail to get help in the early stages of a crisis, says Wallace, which reduces their chances of recovery. They may be removed from hospitals or psychiatric facilities and will often be police officers who end up dealing with the patient. Escalating their condition in these cases only adds to the perception that it is impossible to treat, yet the person may have fared much better if they had accessed treatment sooner.

The Expectation Effect: How Your Mindset Can Transform Your Life by David Robson is published by Canongate (£18.99). To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply