Mental illness is a group of mental, behavioral, and neurodevelopmental disorders that lead to severe disruption of thought, emotional control, and behavior.
They are expressions of underlying biological, psychological, or developmental dysfunctions. They most commonly cause considerable distress or impairment of many aspects of one’s life, for example, family, social, relationship, educational, or work environments.
Most psychiatric disorders are based on recognizable patterns of symptoms as well as behavior.
The International Classification of Diseases, 11th revision (ICD-11) classifies such disorders by, inter alia, symptoms and etiological factors. The following is a simplified overview.
1. Neurodevelopmental Disorders:Â Early-childhood Developmentally Influenced Disorders
Neurodevelopmental disorders refer to behavioral disorders and intellectual disorders that are acquired early in children. It is highly correlated with intellectual, language, and social function impairment.
Examples
Autism Spectrum Disorder (ASD): Diverse Minds, Unique Connections
Autism Spectrum Disorder (ASD) is a condition of social interaction, communication, and behavior. People with ASD generally have special interests and repetitive patterns of behavior.
It is termed a ‘spectrum’ because it is affecting each individual uniquely, with great variation of ability as well as challenge.
Attention Deficit Hyperactivity Disorder (ADHD): The Divergent Mind
ADHD is a common disorder whose symptoms occur early during childhood, while its diagnosis can only be made later.
These symptoms have an impact on attentional ability, activity, and impulsivity. Individuals with ADHD are unable to sustain attention, are excessively active, restless, and behave impulsively without consideration of consequence.
Disorders of Intellectual Development
Disorders of Intellectual Development, otherwise known as Intellectual Disability, are a heterogeneous collection of disorders that occur during development.
These share highly subaverage intellectual functioning (problems with learning, reasoning, and problem-solving) as well as impaired adaptive behavior (deficits in social as well as everyday living skills). These types of impairments are normally determined through standardized tests on the subjects.
Developmental Speech or Language Disorders/Learning Disorders/Motor Coordination Disorders
2. Schizophrenia or Other Primary Psychotic Disorders: Disorders of Reality Perception and Thought Processes
Schizophrenia is one of the severe mental disorders that affects how one perceives and behaves.
They can have unshakable, strong beliefs that are not true (delusions) even when there is sure evidence to the contrary. They can see, hear, smell, taste, or touch things that are not there (hallucinations).
Their thoughts and words get jumbled up. Their behavior might seem disorganized and strange. They can also show fewer emotions and have less motivation for doing things. (Beliefs accepted or practiced in someone’s culture are not considered delusions.)
3. Catatonia: Disturbances in Motor Function and Behavioral Responsiveness
Catatonia is a condition affecting an individual’s mobility and behavior.
The person can become very still, not speaking or moving much, almost like ‘frozen’, or extremely restless and agitated for no apparent reason. Sometimes they might have very strange movements and postures. This condition can be associated with other mental health conditions like Schizophrenia, substance abuse/withdrawal, certain medications, or even some physical conditions like brain injuries.
4. Mood Disorders:Â Beyond Typical Ups and Downs
Mood disorders are a group of mental health conditions where significant changes in a person’s mood occur. These mood changes vary from feeling very low to very high or irritated.
Diagnosis of mood disorders is based on the type of mood episodes and their pattern over time.
The main types of mood episodes are depression (episodes of heightened sorrowfulness and loss of interest), mania (episodes of extreme elation and energy, and potentially irritable mood), hypomania (a less intense version of mania), and mixed episodes (a combination of features of both depression and mania/hypomania).
Bipolar or Related Disorders:Â The Roller-coaster of Moods
Bipolar or related disorders are distinguished by manic, or hypomanic, episodes. These are often alternated with depressive episodes. There can be a mixed episode where both manic/hypomanic as well as depressive symptoms occur within one episode.
These mood swings occur within discrete time intervals. Otherwise, between intervals, the individual is generally functioning normally.
- Bipolar Type 1 Disorder
A single manic or mixed episode is enough for diagnosis. Usually, though, it is identified as a recurrent pattern of alternations with depressive episodes.
- Bipolar Type 2 Disorder
Diagnosed by experiencing one or several hypomanic episodes, as well as one or several depressive episodes.
- Cyclothymic Disorder
Cyclothymic Disorder is a milder but long-lasting mood disorder. The person experiences frequent periods of slightly elevated mood (not high as with mania or hypomania) and periods of mild depression (not low as with full-blown depression).
Depressive Disorders:Â Beyond the Blues
Depressive Disorders are defined by a period of persistent depressed mood (feeling sad, down, or empty) or a significant loss of interest in activities previously pleasurable. These basic characteristics are followed by a mix of other symptoms, including impairment of concentration, marked feelings of worthlessness or of excessive inappropriate guilt, marked feelings of despair, frequent suicidal thoughts or suicidal tendencies, marked change of sleep or of appetite, apparent psychomotor agitation (restlessness) or retardation (slowness of movement and of thinking), and lack of energy or fatigability.
For a diagnosis of a depressive disorder, the individual must never have experienced a manic, hypomanic, or mixed episode. The presence of any of these would indicate bipolar disorder.
- Depressive Disorder (Major Depressive Disorder) (MDD)
A major depressive episode lasts for a minimum of two weeks. However, episodes can last much longer (months).
MDD can occur as one isolated episode or there can be recurrent episodes separated by periods of normal mood.
- Dysthymic Disorder (Persistent Depressive Disorder)
Dysthymic Disorder is characterized by a longer duration of milder symptoms.Â
It is a long-lasting, chronic form of Major Depression, though its symptoms are less severe than those of Major Depression.
Symptoms must have existed for at least two years (one year for children and adolescents), with intervals of two months of normal mood lasting no more than two years.
While present most of the time, it is not usually as intensely debilitating as MDD.
5. Anxiety or Fear-Related Disorders: Excessive Worry, Apprehension, and Fear
These consist of excessive anxiety and fear that cause behavioral disturbance, as well as diffuse impairment of function in everyday life. While fear is a reaction to immediate, near danger, anxiety is more focused on anticipated future dangers.
Examples:
Generalized Anxiety Disorder:Persistent Widespread Worry
Generalized Anxiety Disorder (GAD) is described as a persistent general feeling of apprehension, often described as ‘free-floating anxiety’, or excessive worry about several everyday issues concerning family, health, finance, or work.Â
The other symptoms include muscular tension, restlessness, nervousness, trouble concentrating, irritability, and sleep disturbances.
Panic Disorder:Â Unexpected and Overpowering Waves of Fear and Their Lasting Impact
Panic disorder is characterized by recurrent, uncued episodes of anxiety attacks of overwhelming fear, accompanied by palpitation, sweating, trembling, breathlessness, and fear of dying. These occur with no stimuli or situations as their precipitating factor.
Panic disorder is characterized by a persistent worry of an impending attack or avoidant behavior, causing substantial impairment of function in life.
Agoraphobia:Â Fear of Being Trapped or Helpless
Agoraphobia is defined by intense, realistic fear or anxiety of situations from which one would have difficulty escaping or where help is not available (for example, public places, crowds, being outside the home by oneself, e.g., stores, theatres, waiting in lines).
This anxiety is driven by a fear of adverse outcomes, like panic attacks. These are avoided actively, or else endured with much distress, perhaps only when accompanied by a companion.
Specific Phobia:Â Focused and Persistent Fear Out of Proportion to the Real Danger
Specific phobia is marked by excessive or unusual anxiety or fear that always develops as soon as the individual is confronted with, or even thinks of, specific objects or situations (e.g., animals, flying, heights, small, enclosed spaces, blood, injury).
The fear is out of proportion to the real threat, resulting in avoidance or endurance with extreme distress.
Social Anxiety Disorder: Fear of Social Interactions and Negative Evaluation
Social Anxiety Disorder (social phobia) involves excessive anxiety or fear of being among people, for example, conversation, ordering food or a drink in public environments (public exposure in the spotlight), or public speaking presentations.
The anxiety is based on the fear of being disapproved of if one’s behavior is not appropriate, along with one’s anxiety symptoms. This is followed by avoidance of social settings or tolerating them with much distress.
Separation Anxiety Disorder: Fear of Separation from Attachment Figures
Separation Anxiety Disorder is characterized by excessive anxiety or fear of separation from a key attachment figure (usually parents, caregivers for children; partners, children for adults).
Features include worry about harm to loved ones, staying home from school or work, distress when left by themselves, refusing to sleep alone, and nightmares of being apart.
6. Obsessive-Compulsive or Related Disorders: Recurring, Unwanted Thoughts and Repetitive Behaviors
Individuals with Obsessive-Compulsive and Related Disorders experience a range of conditions characterized by an internal struggle against intrusive, unwanted repetitive thoughts (called obsessions).
These intrusive thoughts generate overwhelming urges that lead them into compulsive actions or become intensely absorbed in specific preoccupations, usually resulting in significant anxiety and impairment in functioning.
Examples:
Obsessive-Compulsive Disorder
Individuals are plagued by distressing and unwanted obsessions – intrusive thoughts, images, or urges that provoke a great deal of anxiety.
These obsessions may lead to compulsions, which are repetitive behaviors or mental acts the person feels compelled to perform in order to alleviate the distress or prevent a feared outcome.
Body Dysmorphic Disorder
Body Dysmorphic Disorder centers on an overwhelming preoccupation with perceived defects in one’s physical appearance, leading to compulsions like mirror checking and seeking reassurance.Â
Hypochondriasis
Hypochondriasis (Illness Anxiety Disorder) involves a persistent and irrational worry about having or acquiring a serious illness, despite medical reassurance, often resulting in repetitive health-related behaviors.
Hoarding Disorder
Hoarding Disorder involves a compulsive need to acquire and accumulate items (no matter how valuable, useful, or useless), coupled with intense anxiety associated with getting rid of them, which causes debilitating clutter and functional impairment.
7. Disorders Specifically Associated With Stress: The Impact of Trauma and Stress
Stress-related disorders are directly associated with stressful or traumatic events or a series of negative experiences.
Not everyone who undergoes a stressful event will develop a disorder, but these conditions would not occur without a triggering stressor.
Stressful events can be within range from normal life events like divorce, socio-economic issues, and bereavement (loss of a loved one) to extremely threatening, horrendous occurrences termed as potentially traumatic events.
Examples
Post-Traumatic Stress Disorder (PTSD):Â Scar Beyond the Trauma
PTSD consists of a cluster of persistent symptoms.
1. Re-experiencing the Trauma: The traumatic event or events are vividly relived in the present through intrusive memories, flashbacks, or nightmares. This is typically associated with intense and overwhelming emotions, particularly fear or horror, and strong physical sensations.
2. Avoidance: Individuals with PTSD avoid thoughts, memories, and reminders of the traumatic event(s).
3. Hyperarousal and Hypervigilance: Indicated by a heightened state of alertness and checking for danger.
Prolonged Grief Disorder:Â Grief Beyond the Expected
Prolonged Grief Disorder is a mental health condition that can occur following the death of an important person in the life of the bereaved.
It is defined by an unrelenting and pervasive style of grief response, predominated by intense longing for the deceased or a persistent preoccupation with the deceased, which is accompanied by significant emotional pain.Â
It can present in many ways, including deep sadness, guilt, anger, denial, blame (of self or other), inability to accept the death, a pervasive feeling of having lost a part of oneself, an inability to feel positive mood, emotional numbness, and difficulty in engaging with social or other activities. What sets this apart and defines it is that this acute reaction to grief lasts for an unusually long time after the loss, far longer than would normally be expected.
Adjustment Disorder:Â Struggle to Adapt to Life Changes and Stressors
Adjustment Disorder is characterized by a maladaptive reaction to psycho-social stressors. These stressors can be ordinary life events such as divorce, illness or disability (personal or affecting a loved one), socio-economic problems (financial problems, job loss), or disputes at home or work.
The disorder is marked by intense ruminating and worrying about the stressor or its effects. This creates emotional distress and functional impairment that are out of proportion to the severity or intensity of the stressor.
8. Dissociative Disorders: Disconnection from Self and Reality
Dissociative disorders are marked by involuntary disruptions or discontinuity of self, its integration, and sense of reality.
This may include their identity, sensations, perceptions, emotions (affects), thoughts, memories, control over body movements, or behavior.
Symptoms are not due to the direct effects of substances or medications (including withdrawal), are not better accounted for by other mental disorders, sleep disorders, neurological disorders, or other medical problems.
Examples:
Dissociative Amnesia:Â Psychological Disconnection from Memories
Dissociative amnesia involves a substantial inability to recall important autobiographical information, typically of a traumatic or stressful nature, that is inconsistent with everyday forgetting.
This is not due to the direct effects of head injury, substances, or other medical problems.
Dissociative Identity Disorder: Multiple Personality Disorder
Dissociative Identity Disorder includes multiple distinct personality states (identities) in the same person, resulting in a fragmented sense of self and agency.
Switching between these identities or, in other words, different “selves”, is associated with shifts in emotions, mood, perceptions, memory, thoughts, and behavior.
At different times, one of these identities will assume control of the person’s consciousness and actions. Memory gaps are common between personality states or when another identity was present. It’s not just about having different moods; it’s a profound disruption in identity and memory.
Depersonalization-Derealization Disorder:Â Feelings of Unreality and Detachment
Depersonalization: Feeling as though you are watching yourself from the outside, or that your thoughts, feelings, body, or actions don’t belong to you. You may seem unreal or strange to yourself.
Derealization: Feeling like the world around you is unreal, or feeling detached from your surroundings. Things may seem dreamlike, distant, foggy, lifeless, colorless, or distorted.
Depersonalization-Derealization Disorder involves persistent or recurrent experiences of either or both.
Despite feeling unreal, the person knows what is real and what is not.
9. Feeding or Eating Disorders
Feeding disorders are behavioral eating disturbances that are unrelated to concerns about body weight or shape.
On the other hand, eating disorders encompass abnormal eating behavior driven by excessive preoccupations with body weight and shape.
Examples:
Anorexia Nervosa:Â Fear of Weight Gain Despite Being Underweight
Anorexia Nervosa is an eating disorder defined by dangerously low body weight, not caused by other health problems or lack of food. Another key indicator is rapid weight loss (e.g., over 20% in 6 months).
This low body weight is sustained over time by persistent behaviors to avoid gaining weight, such as restricted eating whereby individuals eat as little as possible, purging by self-induced vomiting and laxative misuse, alongside excessive exercising, driven by intense fear of gaining weight.
Distorted perception of body weight and shape is also a key feature of Anorexia Nervosa.
Bulimia Nervosa: Secret Cycles of Overeating and Purging
Bulimia Nervosa involves frequent and recurrent episodes of binge eating due to loss of control over eating. These binge eating episodes are followed by compensatory behaviors, such as self-induced vomiting, misuse of laxatives, or excessive exercise to avoid gaining weight.
Individuals with Bulimia Nervosa have intense preoccupations with their body shape and weight, which heavily influence their self-worth.
Binge Eating Disorder:Â The Emotional Appetite
This is characterized by frequent, recurrent binge eating episodes, where the individual develops a subjective loss of control over eating and feels unable to stop eating or limit the type or amount of food consumed. This is typically associated with negative emotions such as guilt or disgust.
However, not like Bulimia Nervosa, here the binge eating episodes are not usually followed by compensatory behaviors to prevent gaining weight.
Pica:Â Craving for the Unusual
Pica is characterized by the regular and sustained ingestion of non-nutritive items, such as non-food objects (clay, soil, chalk, plastic, metal, paper) and large amounts of raw food ingredients (salt, corn flour).
This should be taken into account in individuals who have achieved a developmental age in which they can distinguish between edible and non-edible material.
Rumination-Regurgitation Disorder:Â The Reflux Ritual
This feeding disorder involves the deliberate and repeated bringing up of food previously swallowed back up the mouth (regurgitation). This regurgitated food might then be chewed again (rumination) and swallowed again or deliberately spat out.
This is distinct from vomiting, which is involuntary.
10. Elimination Disorders:Â Beyond Voluntary Control of Excretion
Elimination disorders refer to the recurrent and inappropriate release of bodily waste.
These include enuresis (bed-wetting or urinary incontinence) and encopresis (soiling or fecal incontinence) after achieving developmentally appropriate ages.
These conditions are sometimes a continuation of infant incontinence, or may occur on their own later.
Diagnosis excludes unequivocal incontinence due to other medical conditions, urinary/bowel abnormalities, or laxative/diuretic use.
11. Disorders of Bodily Distress or Bodily Experience: The Subjective Body
These conditions are about feeling troubled or having a distorted sense of one’s own body.
Examples:
Bodily Distress Disorder
This is where someone is very bothered by physical symptoms and pays too much attention to them.
Body Integrity Dysphoria
This is a condition where someone strongly wishes to have a specific disability and feels a deep sense of unease or wrongness about their healthy body.
12. Disorders of Substance Use or Addictive Behaviors: The Brain’s Reward Trap
Examples:
Disorders due to Substance Use
These disorders involve single or repetitive use of psychoactive substances, including some medications.
Initially, these substances are usually felt pleasurable, leading to their repeated use. With prolonged use, they produce dependence in which the individual relies on the particular substance to function. This causes a lot of damage to the person’s mental as well as physical well-being.
E.g.: Alcohol, Cannabis, Opioids, Sedatives/Hypnotics/Anxiolytics, Cocaine, Stimulants (Amphetamine, Methamphetamine), Hallucinogens, Nicotine, etc
Disorders due to addictive behaviors
Addictive behavior disorders encompass repeated, rewarding, and reinforcing behaviors that are not related to dependence-producing agents. The individual feels unable to stop the behavior despite the consequences.
These behaviors can occur in both online and offline activities.
Examples:
- Gambling Disorder
- Gaming Disorder
13. Disorders of Impulse Control: Repeated Failure to Resist Rewarding Urges
Impulse control disorders are characterized by the repeated failure to resist an impulse, drive, or urge to engage in a behavior that is immediately rewarding, despite awareness of long-term consequences to the self or others, distress concerning the behavior, or significant impairment in life.
These disorders can show up in different forms, like an urge to set fires (pyromania), steal things (kleptomania), problematic sexual behavior (compulsive sexual behavior disorder), or sudden bursts of aggression (intermittent explosive disorder).
14. Disruptive Behavior and Dissocial Disorders: Defiance and Rule-Breaking in Kids and Adolescents
Disruptive behavior and dissocial disorders are characterized by ongoing patterns of problem behaviors.
These may be repeated acts of defiance, disobedience, provocation, or transgression (refer to disruptive behavior) or behaviors that continually violate the basic rights of others or primary age-appropriate societal norms, rules, or laws (refer to dissocial behavior).
These disorders, such as Oppositional Defiant Disorder and Conduct-Dissocial Disorder, usually, but not always, emerge during childhood.
15. Personality Disorders: The Spectrum of Self
Personality disorders are essentially long-lasting and troublesome patterns in how an individual operates with their own self and others.
Difficulties with self-functioning can manifest as problems with identity (an ill-defined self-concept), self-worth (unstable or negative self-esteem), the accuracy of self-definition (distorted self-perception), and self-direction (lack of clear goals or internal motivation).
Interpersonal dysfunction involves trouble initiating, developing, and maintaining close and mutually satisfying interpersonal relationships, deficits in the capacity to understand others’ perspectives, and impaired conflict management in interpersonal relationships.
These disturbances manifest in maladaptive patterns of cognition (how one thinks about oneself, others, and events), emotional experience (intensity and appropriateness of feelings), emotional expression (how emotions are displayed), and behavior.
Often are pervasive across a spectrum of personal and social situations, not limited to specific relationships or social roles, these are inflexible or poorly regulated.
16. Paraphilic Disorders:Â Atypical Sexual Arousal, Non-Consent, and Distress
Paraphilic disorders are defined by persistent and intense patterns of atypical sexual arousal involving individuals unwilling or unable to consent, where the individual has acted on these sexual urges or is markedly distressed.
They can also involve arousal patterns with consenting parties or solitary behaviors if those are coupled with considerable distress or risk of harm.
Essentially, this centers on the lack of consent and distress.
17. Factitious Disorders:Â Faking Illness for Attention
It’s a complex mental health condition in which an individual purposefully pretends to be physically or mentally ill, or they might make another person, like a child, look sick.
They may fake symptoms, aggravate already existing ones, or even deliberately injure themselves to receive medical attention or to be seen as unwell.
This is marked by an intentional deception without identifiable external gain, unlike malingering.
18. Neurocognitive Disorders: Acquired Cognitive Decline
Neurocognitive disorders are a group of conditions characterized by a marked decline in a person’s cognitive functioning. While neurodevelopmental disorders involve cognitive deficits present from birth or typically arising in childhood, neurocognitive disorders represent a loss of previously acquired cognitive abilities in an individual who had her or his cognitive capacities already developed.
Though a number of mental health conditions, such as schizophrenia and bipolar disorders, can lead to some cognitive issues, neurocognitive disorders are uniquely defined by cognitive impairment as the primary feature.
Examples:
Delirium:Â The Transient Disruption of Awareness
This is an acute, morbid medical condition characterized by a rapid onset of disturbances in attention, orientation, and overall awareness. One defining feature of delirium is the temporality of its symptoms.
It usually presents as significant confusion and a broad impairment in the function of multiple cognitive domains. In addition to confusion, delirium often involves behavioral and mood changes. Also, disruption of the sleep-wake cycle is common, even a reversal of day-night pattern. Delirium can be triggered by multiple factors, including the direct physical effects of a medical condition or a substance or medication, or withdrawal from these substances.
Amnestic Disorder:Â The Brain’s Memory Lapse
The amnestic disorder is a condition that is represented mainly by significant memory impairment that is not expected for a person, given his/her age and the overall level of cognitive functioning at the previous amount. This constitutes a marked decline from their previous abilities, and happens in the absence of other major cognitive deficits being the primary issue.
The core feature of amnestic disorder is an inability to acquire new memories, learn new information, and/or retain new information. Individuals may also have difficulty recalling previously learned information. Often, recent memory is more impaired than remote memory.
The amnestic disorder is generally considered to be due to an underlying acquired problem with the brain.
Dementia:Â The Gradual Cognitive Descent
Dementia is characterized by a significant decline in cognitive abilities across two or more cognitive domains. It illustrates a stark drop from their previous abilities.
Memory impairment is only one aspect of the cognitive decline seen in the disorder; other domains such as attention, planning, problem-solving, language, social cognition and judgment, psychomotor speed, and visuospatial abilities are also affected. Additionally, neurobehavioral changes may occur in dementia.
It’s important to understand that the dementia related cognitive impairment is not a part of normal aging.
Acquired conditions affecting the brain, such as a disease of the nervous system (e.g., Alzheimer’s disease, Stroke), psychoactive substances, certain medications, etc, are commonly accepted as a cause of dementia.
19. Mental or Behavioral Disorders Associated with Pregnancy, Childbirth, and Puerperium
These refer to the mental health and behavioral changes that arise during pregnancy and the puerperium – the period of 6 weeks after delivery.
Mood symptoms and/or psychotic symptoms may present.
The Bottom Line
So, we’ve traveled through a glimpse of the vast and varied landscape of mental illness. One thing is clear: The human mind can struggle on a wide spectrum.
The crucial takeaway from this review is this: mental illness exists for real, and has devastating effects on every aspect of life, and ultimately, erodes the very foundation of well-being.
And here is the message of hope: help is within reach!
Effective treatment options are available and constantly evolving. Whether it’s through therapeutic discussions that untangle long-entrenched patterns, medications that help restore balance to brain chemistry, or holistic approaches that heal mind and body, recovery and management are possible.
Therefore, if you see yourself or someone you love reflected in these descriptions, take medical attention seriously.
So, the first vital step is to understand this diverse world of mental illness. It’s not just an intellectual exercise; it’s an invitation to blaze a trail for healing and a better future, even if healing does not always mean a cure.
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