American Academy of Clinical Psychology

MENTAL HEALTH DISORDERS AND DEFINITIONS

Depressive Disorders. These include disorders that affect how you feel emotionally, such as the level of sadness and happiness, and they can disrupt your ability to function, loss of interest in activities, causing significant impairment in daily life. Examples include major depressive disorder and premenstrual dysphoric disorder.
Very Common - More than 3 million US cases per year.
Possible causes include a combination of biological, psychological, and social sources of distress. Increasingly, research suggests these factors may cause changes in brain function, including altered activity of certain neural circuits in the brain.
The persistent feeling of sadness or loss of interest that characterizes major depression can lead to a range of behavioral and physical symptoms. These may include changes in sleep, appetite, energy level, concentration, daily behavior, or self-esteem. Depression can also be associated with thoughts of suicide.
The mainstay of treatment is usually medication, talk therapy, or a combination of the two. Increasingly, research suggests these treatments may normalize brain changes associated with depression.
Requires a medical diagnosis
The persistent feeling of sadness or loss of interest that characterizes major depression can lead to a range of behavioral and physical symptoms. These may include changes in sleep, appetite, energy level, concentration, daily behavior, or self-esteem. Depression can also be associated with thoughts of suicide.
People may experience:
Mood: anxiety, apathy, general discontent, guilt, hopelessness, loss of interest, loss of interest or pleasure in activities, mood swings, or sadness
Behavioral: agitation, excessive crying, irritability, restlessness, or social isolation
Sleep: early awakening, excess sleepiness, insomnia, or restless sleep
Whole body: excessive hunger, fatigue, or loss of appetite
Cognitive: lack of concentration, slowness in activity, or thoughts of suicide
Weight: weight gain or weight loss
Also common: poor appetite or repeatedly going over thoughts

Feeding and Eating Disorders. These disorders include disturbances related to eating that impact nutrition and health, such as anorexia nervosa and binge-eating disorder.
Very Common - More than 3 million US cases per year.
Examples of anxiety disorders include panic attacks, obsessive-compulsive disorder, and post-traumatic stress disorder.
Symptoms include stress that's out of proportion to the impact of the event, inability to set aside a worry, and restlessness.
Treatment includes counseling or medications, including antidepressants.
Usually self-diagnosable
Symptoms include stress that's out of proportion to the impact of the event, inability to set aside a worry, and restlessness.
People may experience:
Behavioral: hypervigilance, irritability, or restlessness
Cognitive: lack of concentration, racing thoughts, or unwanted thoughts
Whole body: fatigue or sweating
Also common: anxiety, excessive worry, fear, feeling of impending doom, insomnia, nausea, palpitations, or trembling Bipolar and Related Disorders. This class includes disorders with alternating episodes of mania — periods of excessive activity, energy and excitement — and depression.
Very Common - More than 3 million US cases per year.
The exact cause of bipolar disorder isn’t known, but a combination of genetics, environment, and altered brain structure and chemistry may play a role.
Manic episodes may include symptoms such as high energy, reduced need for sleep, and loss of touch with reality. Depressive episodes may include symptoms such as low energy, low motivation, and loss of interest in daily activities. Mood episodes last days to months at a time and may also be associated with suicidal thoughts.
Treatment is usually lifelong and often involves a combination of medications and psychotherapy.
Requires a medical diagnosis
Manic episodes may include symptoms such as high energy, reduced need for sleep, and loss of touch with reality. Depressive episodes may include symptoms such as low energy, low motivation, and loss of interest in daily activities. Mood episodes last days to months at a time and may also be associated with suicidal thoughts.
People may experience:
Mood: mood swings, sadness, elevated mood, anger, anxiety, apathy, apprehension, euphoria, general discontent, guilt, hopelessness, loss of interest, or loss of interest or pleasure in activities
Behavioral: irritability, risk taking behaviors, disorganized behavior, aggression, agitation, crying, excess desire for sex, hyperactivity, impulsivity, restlessness, or self-harm
Cognitive: unwanted thoughts, delusion, lack of concentration, racing thoughts, slowness in activity, or false belief of superiority
Psychological: depression, manic episode, agitated depression, or paranoia
Weight: weight gain or weight loss
Sleep: difficulty falling asleep or excess sleepiness
Also common: fatigue or rapid and frenzied speaking

Dementia: A group of thinking and social symptoms that interferes with daily functioning.
Very Common - More than 3 million US cases per year
Not a specific disease, dementia is a group of conditions characterized by impairment of at least two brain functions, such as memory loss and judgment.
Symptoms include forgetfulness, limited social skills, and thinking abilities so impaired that it interferes with daily functioning.
Medications and therapies may help manage symptoms. Some causes are reversible.
Requires a medical diagnosis:
Symptoms include forgetfulness, limited social skills, and thinking abilities so impaired that it interferes with daily functioning.
People may experience:
Cognitive: memory loss, mental decline, confusion in the evening hours, disorientation, inability to speak or understand language, making things up, mental confusion, or inability to recognize common things
Behavioral: irritability, personality changes, restlessness, lack of restraint, or wandering and getting lost
Mood: anxiety, loneliness, mood swings, or nervousness
Psychological: depression, hallucination, or paranoia
Muscular: inability to combine muscle movements or unsteady walking
Also common: falling, jumbled speech, or sleep disorder

ADHD / Attention-Deficit Hyperactivity Disorder: A chronic condition including attention difficulty, hyperactivity, and impulsiveness.
Very Common - More than 3 million US cases per year.
ADHD often begins in childhood and can persist into adulthood. It may contribute to low self-esteem, troubled relationships, and difficulty at school or work.
Symptoms include limited attention and hyperactivity.
Treatments include medication and talk therapy.
Requires a medical diagnosis
Symptoms include limited attention and hyperactivity.
People may experience:
Behavioral: aggression, excitability, fidgeting, hyperactivity, impulsivity, irritability, lack of restraint, or persistent repetition of words or actions
Cognitive: absent-mindedness, difficulty focusing, forgetfulness, problem paying attention, or short attention span
Mood: anger, anxiety, boredom, excitement, or mood swings
Also common: depression or learning disability

Schizophrenia Spectrum and other Psychotic Disorders. Psychotic disorders cause detachment from reality — such as delusions, hallucinations, and disorganized thinking and speech. The most notable example is schizophrenia, although other classes of disorders can be associated with detachment from reality at times.A disorder that affects a person's ability to think, feel, and behave clearly.
Common - More than 200,000 US cases per year.
The exact cause of schizophrenia isn't known, but a combination of genetics, environment, and altered brain chemistry and structure may play a role.
Schizophrenia is characterized by thoughts or experiences that seem out of touch with reality, disorganized speech or behavior, and decreased participation in daily activities. Difficulty with concentration and memory may also be present.
Requires a medical diagnosis
Schizophrenia is characterized by thoughts or experiences that seem out of touch with reality, disorganized speech or behavior, and decreased participation in daily activities. Difficulty with concentration and memory may also be present.
People may experience:
Behavioral: social isolation, disorganized behavior, aggression, agitation, compulsive behavior, excitability, hostility, repetitive movements, self-harm, or lack of restraint
Cognitive: thought disorder, delusion, amnesia, belief that an ordinary event has special and personal meaning, belief that thoughts aren't one's own, disorientation, memory loss, mental confusion, slowness in activity, or false belief of superiority
Mood: anger, anxiety, apathy, feeling detached from self, general discontent, loss of interest or pleasure in activities, elevated mood, or inappropriate emotional response
Psychological: hallucination, paranoia, hearing voices, depression, fear, persecutory delusion, or religious delusion
Speech: circumstantial speech, incoherent speech, rapid and frenzied speaking, or speech disorder
Also common: fatigue, impaired motor coordination, or lack of emotional response

Obsessive-Compulsive and Related Disorders. These disorders involve preoccupations or obsessions and repetitive thoughts and actions. Examples include obsessive-compulsive disorder, hoarding disorder and hair-pulling disorder (trichotillomania).
Common - More than 200,000 US cases per year.
Obsessive-compulsive disorder is characterized by unreasonable thoughts and fears (obsessions) that lead to compulsive behaviors.
OCD often centers on themes such as a fear of germs or the need to arrange objects in a specific manner. Symptoms usually begin gradually and vary throughout life.
Requires a medical diagnosis
OCD often centers on themes such as a fear of germs or the need to arrange objects in a specific manner. Symptoms usually begin gradually and vary throughout life.
People may experience:
Behavioral: compulsive behavior, agitation, compulsive hoarding, hypervigilance, impulsivity, meaningless repetition of own words, repetitive movements, ritualistic behavior, social isolation, or persistent repetition of words or actions
Mood: anxiety, apprehension, guilt, or panic attack
Psychological: depression or fear

Autism:  A serious developmental disorder that impairs the ability to communicate and interact.
Common - More than 200,000 US cases per year.
Autism spectrum disorder impacts the nervous system.
The range and severity of symptoms can vary widely. Common symptoms include difficulty with communication, difficulty with social interactions, obsessive interests, and repetitive behaviors.
Requires a medical diagnosis
The range and severity of symptoms can vary widely. Common symptoms include difficulty with communication, difficulty with social interactions, obsessive interests, and repetitive behaviors.
People may experience:
Behavioral: inappropriate social interaction, poor eye contact, compulsive behavior, impulsivity, repetitive movements, self-harm, or persistent repetition of words or actions
Developmental: learning disability or speech delay in a child
Cognitive: intense interest in a limited number of things or problem paying attention
Psychological: unaware of others' emotions or depression

PTSD / Post Traumatic Stress Disorder: A disorder in which a person has difficulty recovering after experiencing or witnessing a terrifying event.
Very Common - More than 3 million US cases per year.
The condition may last months or years, with triggers that can bring back memories of the trauma accompanied by intense emotional and physical reactions.
Symptoms may include nightmares or unwanted memories of the trauma, avoidance of situations that bring back memories of the trauma, heightened reactions, anxiety, or depressed mood.
Treatment includes different types of trauma-focused psychotherapy as well as medications to manage symptoms.
Requires a medical diagnosis
Symptoms may include nightmares or unwanted memories of the trauma, avoidance of situations that bring back memories of the trauma, heightened reactions, anxiety, or depressed mood.
People may experience:
Behavioral: agitation, irritability, hostility, hypervigilance, self-destructive behavior, or social isolation
Psychological: flashback, fear, severe anxiety, or mistrust
Mood: loss of interest or pleasure in activities, guilt, or loneliness
Sleep: insomnia or nightmares
Also common: emotional detachment or unwanted thoughts

Neurodevelopmental disorders. This class covers a wide range of problems that usually begin in infancy or childhood, often before the child begins grade school. Examples include autism spectrum disorder, attention-deficit/hyperactivity disorder (ADHD) and learning disorders.

Trauma- and Stressor-Related Disorders. These are adjustment disorders in which a person has trouble coping during or after a stressful life event. Examples include post-traumatic stress disorder (PTSD) and acute stress disorder.

Dissociative Disorders. These are disorders in which your sense of self is disrupted, such as with dissociative identity disorder and dissociative amnesia.

Somatic Symptom and Related Disorders. A person with one of these disorders may have physical symptoms that cause major emotional distress and problems functioning. There may or may not be another diagnosed medical condition associated with these symptoms, but the reaction to the symptoms is not normal. The disorders include somatic symptom disorder, illness anxiety disorder and factitious disorder.

Elimination disorders. These disorders relate to the inappropriate elimination of urine or stool by accident or on purpose. Bed-wetting (enuresis) is an example.

Sleep-Wake Disorders. These are disorders of sleep severe enough to require clinical attention, such as insomnia, sleep apnea and restless legs syndrome.

Sexual dysfunctions. These include disorders of sexual response, such as premature ejaculation and female orgasmic disorder.

Gender dysphoria. This refers to the distress that accompanies a person's stated desire to be another gender.

Disruptive, impulse-control and conduct disorders. These disorders include problems with emotional and behavioral self-control, such as kleptomania or intermittent explosive disorder.

Substance-related and addictive disorders. These include problems associated with the excessive use of alcohol, caffeine, tobacco and drugs. This class also includes gambling disorder.

Neurocognitive disorders. Neurocognitive disorders affect your ability to think and reason. These acquired (rather than developmental) cognitive problems include delirium, as well as neurocognitive disorders due to conditions or diseases such as traumatic brain injury or Alzheimer's disease.

Personality disorders. A personality disorder involves a lasting pattern of emotional instability and unhealthy behavior that causes problems in your life and relationships. Examples include borderline, antisocial and narcissistic personality disorders.

Paraphilic disorders. These disorders include sexual interest that causes personal distress or impairment or causes potential or actual harm to another person. Examples are sexual sadism disorder, voyeuristic disorder and pedophilic disorder.

Other mental disorders. This class includes mental disorders that are due to other medical conditions or that don't meet the full criteria for one of the above disorders.