864 articles
List of suicide crisis lines
The list of suicide crisis lines provides free, confidential emotional support and referrals to people in crisis. The first such service opened in London, England, in 1953.
Lobotomy
Lobotomy (leucotomy), a discredited psychosurgical procedure severing prefrontal-thalamic connections, introduced by Egas Moniz in 1935, Nobel-recognized 1949, popularized by Walter Freeman's transorbital method, abandoned after antipsychotics emerged in the 1950s.
Locus of control
Locus of control, proposed by Julian Rotter in 1954, is the belief about whether life outcomes stem from one's own actions (internal) or external forces like luck or others (external), measured by scales such as Rotter's I-E and Levenson's I-P-C.
Logotherapy
Logotherapy, also called meaning-centered therapy, is a psychotherapy developed by Austrian psychiatrist Viktor Frankl, based on the idea that people are primarily motivated by a will to meaning.
Long-term effects of cannabis
The long-term effects of cannabis are the persistent health consequences of repeated use, including doubled psychosis risk in heavy users, cannabis use disorder, and cognitive harm from adolescent use.
Low frustration tolerance
Low frustration tolerance (LFT), also called frustration intolerance, is a diminished ability to regulate emotions and behavior when frustrated, classified in the ICD-11 under personality features.
Low self-esteem
Low self-esteem is a persistently negative self-evaluation, ICD-11 code MB28.9, not a disorder itself. It is linked to depression and anxiety; CBT and related interventions show moderate benefits in adults.
Lucid dream
Lucid dream: a dream in which the sleeper knows they are dreaming, also called klartraum. Verified by eye signals since Hearne's 1975 experiment; occurs in REM sleep; about 55% lifetime prevalence; MILD is the most effective induction technique.
Madness and Civilization
Madness and Civilization (Folie et déraison, 1961) is Michel Foucault's history of madness in the Age of Reason, arguing confinement of the mad was social exclusion, not medicine; the English Richard Howard translation is abridged by 300 pages.
Major depressive disorder
Major depressive disorder (MDD, clinical depression): a DSM-5-defined mood disorder of two-week depressive episodes. Formerly melancholia; affects 8.3% of US adults yearly; treated with psychotherapy, antidepressants, ECT, esketamine.
Major depressive episode
Major depressive episode: a period of at least two weeks with depressed mood or anhedonia plus five of nine DSM-5 symptoms causing impairment; basis of major depressive disorder, near-identical in ICD-11.
Malignant narcissism
Malignant narcissism, coined by Erich Fromm (1964) and developed by Otto Kernberg (1984), is a non-DSM theoretical construct combining narcissistic personality disorder with antisocial behavior, ego-syntonic sadism, and paranoia, placed between NPD and psychopathy on a severity continuum.
Mania
Mania: abnormally elevated, expansive, or irritable mood with increased energy lasting at least a week, the hallmark of bipolar I disorder; from Greek μανία, first described by Hippocrates, treated with lithium, valproate, or antipsychotics.
Marbach-Schaaf neurodevelopmental syndrome
Marbach-Schaaf neurodevelopmental syndrome (MASNS, OMIM 619680), also called global developmental delay-hypotonia-high pain tolerance syndrome, is an ultra-rare autosomal dominant PRKAR1B-related disorder with developmental delay, autism, and pain insensitivity, distinct from Schaaf-Yang syndrome.
MDMA-assisted psychotherapy
MDMA-assisted psychotherapy (MDMA-AT, midomafetamine) is an experimental PTSD treatment pairing supervised MDMA sessions with structured therapy; Phase 3 trials showed benefit, but the FDA declined approval in August 2024.
Medical social work
Medical social work, also called hospital social work, is a clinical social work field addressing the social and psychological dimensions of illness, beginning at Massachusetts General Hospital in 1905.
Melancholia
Melancholia, also called melancholic depression or MDD with melancholic features, is a severe depressive syndrome marked by anhedonia, mood nonreactivity, and psychomotor disturbance; historically attributed to black bile, now a DSM-5 specifier with distinct treatment response.
Memory clinic
Memory clinic: specialist multidisciplinary outpatient service (memory assessment service) assessing and diagnosing dementia and MCI; began in the 1980s, expanded by the UK 2009 dementia strategy, now adopting blood biomarkers.
Menke-Hennekam syndrome
Menke-Hennekam syndrome (MKHK) is a rare autosomal dominant neurodevelopmental disorder caused by variants in CREBBP or EP300, first described in 2016 and distinct from Rubinstein-Taybi syndrome.
Menninger Foundation
Menninger Foundation, Topeka, Kansas psychiatric organization founded by the Menninger family; clinic 1919, sanitarium 1925, foundation 1941; moved to Houston with Baylor College of Medicine in 2002-2003.
Mental disorder
A mental disorder, also called a psychiatric or psychological disorder, is a clinically significant disturbance in cognition, emotion, or behavior, usually with distress or impairment; anxiety and depression are most common.
Mental health
Mental health: WHO defines it as well-being beyond absence of illness. About 1.2 billion people (1 in 7) live with a mental disorder; anxiety and depression dominate; treatment gap is severe, under 9% adequate depression care.
Mental health professional
Mental health professional: umbrella term for trained providers such as psychiatrists, psychologists, social workers, nurses, counselors, and peer workers; differs by degree, licensure, prescribing rights, and roles in care delivery.
Mental Health Services (concept)
Mental health services are organized services providing mental health care, MeSH descriptor D008605 since 1967. Covers deinstitutionalization history, community models such as community mental health centers and assertive community treatment, effectiveness evidence, and access barriers.
Messiah complex
Messiah complex: colloquial term for a compulsion to redeem others or the world, sometimes with delusions of being divine; not a diagnosis, covered as grandiose religious delusions in psychosis, 18.3% pooled prevalence.
Metacognitive therapy
Metacognitive therapy (MCT) is a psychotherapy, developed by Adrian Wells, that treats anxiety and depression by changing beliefs about one's own thinking rather than the content of thoughts.
Metacognitive training
Metacognitive training (MCT) is a manualized group psychotherapy for psychosis that uses exercises to modify cognitive biases driving delusions, with free materials in 37 languages.
Meth mouth
Meth mouth, also called crank decay, is severe tooth decay, gum disease, and tooth wear in chronic methamphetamine users, driven mainly by dry mouth, sugary drinks, and poor oral hygiene rather than direct chemical effects.
Mild intellectual disability
Mild intellectual disability: a developmental disability with IQ below about 70, adaptive behavior deficits, and onset before adulthood; prevalence 0.7–1.3%, often grouped with borderline intellectual functioning (IQ 71–84) as MBID.
Mild neurocognitive disorder
Mild neurocognitive disorder (mild NCD, DSM-5 2013; ICD-11 6D71) is a modest, measurable cognitive decline beyond normal aging, roughly matching mild cognitive impairment, with independence preserved and ten etiologic specifiers.