The Most Common Mental Disorders

The Most Common Mental Disorders

The human mind is incredibly complex, and although it’s something we’ve been thinking about and studying for thousands of years, we’re pretty much nowhere near really figuring out how we work. We still discover new things about ourselves on a regular basis, from understanding how intelligence develops and what factors determine personality to figure out what is and isn’t normal human behavior, and how a healthy mind can best avoid becoming ill.

For the world of psychology, the big responsibility is figuring out how to solve the problems of the human mind – its mental disorders. There are many mental disorders and symptoms, and all of them range from mild to ruinous in severity and capacity. Some mental disorders make it difficult to remember things and may make us a little more irritable, or prone to a loss of temper. They might kill our mood or send us into swings of irrational emotion. Others toy with our mind, putting things in our world that aren’t really there, letting us hear and feel things that don’t exist.

The modern human mind is an evolutionary development that took millions of years and truly materialized a few dozen thousand years ago, and we’re still doing our homework on it – and will be for a very long time.

When it comes to these common mental disorders and the progress we’ve made in studying them and discovering as much about them as possible, it’s humbling to see how much of the progress we’ve made towards diagnosing and helping people with these disorders is rather recent. We just don’t know much and are constantly learning more. But what we do know can help a lot of people put their experiences into context, and help them improve and even thrive under dire conditions.

Keep in mind that while these are basic explanations of what we know about our worst mental enemies, every single one of these descriptions is written to inform you on the basics of mental illness, and not act as diagnostic tools. Only a professional can help you definitively figure out if you’re struggling with your mental health.

Substance Abuse and Dependence

These are actually two separate categories according to the DSM, but it helps to explain them together due to their obviously exclusive relationship. Abuse doesn’t really mean dependence according to modern addiction literature, and the matter is a difference between the physical issue of a dependence on whatever drug of choice someone has and the abuse of a drug for the purpose of self-medication.

To be clearer, substance abuse is defined by modern psychiatric standards as a maladaptive behavior. That’s when you’ve got a problem, and your solution for coping with said problem – like an abnormal amount of stress – is to do something that might seem to help you in the short-term but will cause you an even greater amount of stress and potential damage in the future. The simplest analogy is shooting you in the foot to stop a headache, although a far more realistic example is drinking alcohol to relieve stress after work – night after night after night.

When a drug is used for over a year for the explicit purpose of coping with stress or other problems, and you’re escalating in reckless behavior (like drinking on the job), you’re probably eligible for a professional diagnosis of abuse.

Dependence is something else. That’s when your body develops a physical resistance or tolerance to a drug, and you take incrementally larger amounts of it to make up for the fact. Eventually, this drives you to a point where trying to stop causes you to go into withdrawal, a painful and sometimes deadly experience if not done properly and with medical attention.

The two are intricately related and often occur together, but not everyone suffering from addiction can be diagnosed with both. Dependence is treated through the highly studied medical art of rehab – clients basically get medical assistance in weaning their body off a drug, and then they get psychiatric assistance to beat their addiction. Some people get off drugs completely on their own, but it’s never an easy experience.


Anxiety is a contender for the top of the list in terms of the world’s most common mental illness. It’s an incredibly diverse diagnosis, with disorders ranging from extremely mild to highly severe. All the world’s phobias are encompassed within the anxiety spectrum, together with specific diagnoses like social anxiety, and the more general anxiety disorder.

To put it in simpler terms, anxiety is fear. That’s really the best way to describe it. An anxiety disorder is an extraordinary or unnatural fear of something or several things in life, manifesting in different ways. Social anxiety disorders, for example, are the fear and worry that you might embarrass yourself, or that you’re incapable of presenting yourself in public without a massive blunder. It can be mild or so bad that you develop an obsessive compulsive disorder, the urge to utilize compulsive and obsessive behavior to distract yourself or save yourself from a certain fear.

Like any mental illness, anxiety can be inherent, or it can develop. Post-traumatic stress disorder, or PTSD, is usually diagnosed after an incredibly traumatic or series of traumatic events causes you to break down into a state of anxiety, making the event a painful scar in your life. Over 40 million Americans struggle with anxiety in a year, the most common example being social anxiety. This isn’t to be confused with shyness or introversion, both of which are normal human behavior – rather, it’s the fear or total irrational aversion to certain forms of human contact.


More than 15 million Americans struggle with major depression, and several million more struggles with depressive symptoms, falling somewhere along the depression spectrum. Another term for the depression spectrum is mood disorders, a collection of different disorders related to depression and depressive symptoms, from manic depression to cyclothymia. The basic idea is that a mood disorder is one where your regular ups and downs are replaced by severe ups and downs, or just a lot of really bad downs.

Depression isn’t just feeling sad, or having a down-time emotionally. We naturally experience quite a few of the symptoms of a depression while mourning and grieving the loss of a loved one, or while coping with a sad event that might’ve severely affected us. Yet our natural inclination is to live through that depressive period, then recover and move on. It might make us a little solemn or sad to think about it, but it’s over.

Major depression may develop because of a traumatic event, or completely on its own, and major depression is diagnosed by exhibiting several depressive symptoms for much longer than is normal.

A depression can pass on its own, or become a lifelong problem. Depression isn’t a joke or just a matter of feeling sad – severe depression includes regular thoughts of hopelessness and suicide and instances of self-harm. Depression is the leading cause of disability among young people, stripping people of the will to live and the motivation to work. And it’s a growing problem among our youth.

Treating depression isn’t easy. Not only can it take a long time to make progress through therapy and medication, but those struggling with depression quite often also struggle with anxiety or another mental disorder. Common symptoms, as a result, are an incredibly low self-esteem and trouble in social situations, ranging from extreme shyness to fear of contact.

Another common form of depression is manic depression, which was formerly known as bipolar disorder. While it’s a separate diagnosis from major depression, both occur on the depressive spectrum. Manic depression is best described as a severe depression with manic episodes – these are basically episodes of extreme elation and a hyper confidence that often inspires recklessness.

Among the roughly 5.7 million Americans struggling with manic depression, the experience is generalized as swinging between severe sadness and euphoria, but a manic state can often translate into abject fear and paranoia rather than happiness. It’s important to understand that – it’s not really accurate to describe manic depression as a mix of happy and sad, it’s a bit more complicated than that.

Mania and happiness aren’t the same things – mania is a state of mental hyperactivity, the opposite of a depressive phase, where instead of a lack of motivation you find yourself motivated towards anything. However, this is also highlighted by over activity and delusions of grandeur, which can make for a scary combination. Even in less severe cases, such a cyclothymia – a much milder manic depression – neither the depressive nor manic symptoms are typically appreciated.

Eating Disorders

Last on this list and a fairly commonly diagnosed set of disorders are eating disorders. Typically, when we think about an eating disorder, we picture bulimia or anorexia. However, binge eating is also an incredibly potent issue among Americans and a driving factor in other mental disorders and general health issues.

An eating disorder is any mental disorder characterized by severe irregularities with the way a person eats food and handles their weight. Extreme fluctuations in weight gain and weight loss, as well as periods of starvation or binge-eating, are signs of an eating disorder. Eating disorders are highly treatable, if diagnosed properly and addressed with the proper medication and treatment for the job.

About 30 million Americans have an eating disorder, a drastic percentage of which are female, minorities and/or transgender. While over half of the diagnosed cases of bulimia in the country are at least partially genetically caused, stress is a massive factor in the development of an eating disorder. Like substance abuse, sometimes it’s a matter of maladaptive behavior – short-term reward, long-term damage. This is especially true for cases of a binge eating disorder, where roughly half of all cases is diagnosed alongside either anxiety, depression, or both.

The statistics are alarming, both for anorexia/bulimia and binge eating. Other less common eating disorders such as restrictive food intake and diabulimia are also taking their toll on the American population – and our general solution is support and therapy. Medication does less in cases of an eating disorder than it might for other disorders, perhaps due to the complex nature of how an eating disorder develops.

When it’s not genetic, eating disorders may be related to a low self-esteem and major body issues, including a powerful feeling of self-consciousness regarding personal weight, and body dysmorphia – an anxiety disorder that causes someone to see themselves in a highly negative and different light from reality, from feeling inadequate in size and weight to considering a minor personal imperfection as a highly visible flaw.

Treating Our Mental Illnesses

Mental illness is a highly individual manner, where every case has its own nuances and unique circumstances that make diagnosis and treatment challenging. Sometimes, we like to make sweeping allegations and simplistic statements about certain disorders to help simplify the complex, but that only hurts the credibility of psychology. It’s a lot more realistic to think about these disorders as categories of related symptoms, many of which are closely related and tie into a problem solved by a specific set of therapies and medication.

There are some generalities that can be said about mental disorders, though. For one, a mental disorder is never guaranteed. People can go through untold amounts of trauma and not develop PTSD. Some people still develop high levels of anxiety without having experienced trauma or abuse.

While one breakup might’ve been enough to set off a depression, that doesn’t mean the next one will do the same for the same person. There are too many factors and too many variables to give a perfect explanation of how any individual case of mental illness came to pass – the best we can do is help you understand why you might’ve been affected, and what options you have towards getting better.

Things get even more complicated when you realize that many of these disorders – such as anxiety, depression, and bulimia – act together, making a clear diagnosis tough to call. It’s important not to get too hung up on labels – what we call things doesn’t ultimately matter when we focus on tackling an individual’s problem as a whole.