Evidence-Based Supplement & Herb Guides

Irritability Disorder: Symptoms, Signs, Causes, and Diagnostic Context

Irritability disorder can describe severe, persistent, or impairing anger and frustration patterns. Learn how symptoms, causes, risk factors, diagnostic context, and warning signs are evaluated.

Irritability can be more than being annoyed, impatient, or “in a bad mood.” In mental health, clinically significant irritability means a person is unusually...

Involuntary emotional expression disorder in Neurological Conditions

Learn what involuntary emotional expression disorder is, how it differs from mood disorders, which neurological conditions can cause it, and when evaluation may matter.

Involuntary emotional expression disorder is a condition in which a person has sudden episodes of laughing, crying, or other emotional expression that feel difficult...

Intrusive thoughts disorder Explained: Symptoms, Risk Factors, and Complications

Clear, clinically grounded overview of intrusive thoughts, including symptoms, common themes, causes, risk factors, diagnostic distinctions, complications, and when urgent evaluation may be needed.

Intrusive thoughts can feel alarming because they often arrive suddenly, clash with a person’s values, and focus on topics the person would never choose...

Internalizing Disorder Signs, Related Conditions, and Complications

Learn what internalizing disorder means, how symptoms can appear in children, teens, and adults, what causes and risk factors may contribute, and when evaluation may be important.

Internalizing disorder is a broad mental health term for patterns of emotional distress that are mainly directed inward. Instead of showing up primarily as...

Intermittent Explosive Disorder Overview, Signs, Outbursts, and Related Conditions

Learn what intermittent explosive disorder is, how symptoms and outbursts can appear, what causes and risk factors may contribute, and when evaluation is important.

Intermittent explosive disorder is a mental health condition in which a person has repeated episodes of impulsive, aggressive anger that are much more intense...

Intellectual Disability (Intellectual Developmental Disorder): Symptoms, Signs, Causes, and Complications

Intellectual disability affects reasoning, learning, daily living skills, and adaptive functioning. Learn the signs, causes, risk factors, diagnostic context, overlapping conditions, and complications that may require professional evaluation.

Intellectual disability, also called intellectual developmental disorder in some diagnostic systems, is a neurodevelopmental condition that begins during the developmental period and affects both...

Insomnia Disorder Overview, Symptoms, Signs, Causes, Risk Factors, and Complications

A clear guide to insomnia disorder, including how it differs from ordinary poor sleep, the symptoms and signs to watch for, common causes, risk factors, related conditions, complications, and when professional evaluation may be important.

Insomnia disorder is more than an occasional bad night. It describes a persistent pattern of difficulty falling asleep, staying asleep, waking too early, or...

Insecure attachment disorder: Overview and Key Warning Signs

Learn what insecure attachment disorder means, how insecure attachment differs from formal attachment disorders, and what symptoms, causes, risks, and complications may require professional evaluation.

“Insecure attachment disorder” is a phrase many people use when attachment patterns feel painful, confusing, or disruptive. Clinically, however, it is important to separate...

Inhibited personality disorder Signs, Risk Factors, and Related Conditions

Understand inhibited personality disorder, its overlap with avoidant personality disorder, key symptoms, possible causes, diagnostic context, similar conditions, and complications that may require professional evaluation.

Inhibited personality disorder is not the most common current diagnostic name in modern clinical practice. When people use this phrase, they are usually referring...

Inflexible personality disorder: Overview, symptoms, signs, causes, and complications

Learn what inflexible personality disorder usually means, how it overlaps with obsessive-compulsive or anankastic personality patterns, what signs may appear in daily life, and when professional evaluation may be important.

“Inflexible personality disorder” is not usually used as a stand-alone formal diagnosis in current psychiatric classification systems. In everyday language, it often describes a...

Infantile autism Early Signs, Behavioral Symptoms, and Complications

Clear, condition-focused overview of infantile autism, including early signs, core symptoms, possible causes, risk factors, diagnostic context, similar conditions, and complications.

Infantile autism is an older clinical term for what is now usually described as autism spectrum disorder when the features are present from early...

Induced delusional disorder: Symptoms, Signs, and Relationship Patterns

Clear explanation of induced delusional disorder, including shared delusions, relationship signs, common symptoms, risk factors, diagnostic context, complications, and urgent warning signs.

Induced delusional disorder is a rare psychotic condition in which a delusional belief becomes shared between two or more closely connected people. It is...

Inadequacy Neurosis: Meaning, Symptoms, Causes, and Mental Health Context

Learn what inadequacy neurosis means today, how it relates to low self-worth and anxiety, and when persistent feelings of inferiority may need professional evaluation.

“Inadequacy neurosis” is an older mental health term that is not used as a formal diagnosis in modern DSM or ICD classification systems. Today,...

Impulse-Control Disorder Overview: What It Means and When Evaluation Matters

Impulse-control disorders involve repeated difficulty resisting harmful urges or aggressive reactions. Learn the main symptoms, signs, causes, risk factors, diagnostic context, and possible complications.

Impulse-control disorders involve repeated difficulty resisting urges, impulses, or aggressive reactions that can lead to harm, distress, legal problems, relationship strain, or serious disruption...

Impulse dysregulation disorder: aggressive, risky, and compulsive behavior patterns

Learn what impulse dysregulation means, how it may appear, what conditions it can resemble, and when repeated impulsive behavior may need professional evaluation.

Impulse dysregulation refers to a pattern of difficulty controlling urges, reactions, or behaviors even when the person understands that the action may be harmful,...

Imposter syndrome: Symptoms, Signs, Causes, and Mental Health Effects

Learn what imposter syndrome means, how it shows up, what causes it, who is most at risk, what it can be confused with, and when professional evaluation may matter.

Imposter syndrome describes a pattern of persistent self-doubt in which a capable person has trouble accepting their own competence, even when there is clear...