The symptoms of<unk>  may be caused by serious psychiatric disorders such as schizophrenia, a number of medical illnesses, and trauma.<unk>  may also be temporary or transient, and be caused by medications or substance use disorder (substance-induced<unk> . Normal states Brief hallucinations are not uncommon in those without any psychiatric disease, including healthy children. Causes or triggers include: * Falling asleep and waking: hypnagogic and hypnopompic hallucinations * Bereavement, in which hallucinations of a deceased loved one are common * Severe sleep deprivation *Extreme stress Trauma and Stress Traumatic life events have been linked with an elevated risk of developing psychotic symptoms. Childhood trauma has specifically been shown to be a predictor of adolescent and adult<unk> . Individuals with psychotic symptoms are three times more likely to have experienced childhood trauma (e.g., physical or sexual abuse, physical or emotional neglect) than those in the general population. Increased individual vulnerability toward<unk>  may interact with traumatic experiences promoting an onset of future psychotic symptoms, particularly during sensitive developmental periods. Importantly, the relationship between traumatic life events and psychotic symptoms appears to be dose-dependent in which multiple traumatic life events accumulate, compounding symptom expression and severity. However, acute, stressful events can also trigger brief psychotic episodes. Trauma prevention and early intervention may be an important target for decreasing the incidence of psychotic disorders and ameliorating its effects. Neuroticism, a personality trait associated with vulnerability to stressors, is an independent predictor of the development of<unk> . Psychiatric disorders From a diagnostic standpoint, organic disorders were believed to be caused by physical illness affecting the brain (that is, psychiatric disorders secondary to other conditions) while functional disorders were considered disorders of the functioning of the mind in the absence of physical disorders (that is, primary psychological or psychiatric disorders). Subtle physical abnormalities have been found in illnesses traditionally considered functional, such as schizophrenia. The DSM-IV-TR avoids the functional/organic distinction, and instead lists traditional psychotic illnesses,<unk>  due to general medical conditions, and substance-induced<unk> . Primary psychiatric causes of<unk>  include the following: * schizophrenia and schizophreniform disorder * affective (mood) disorders, including major depression, and severe depression or mania in bipolar disorder (manic depression). People experiencing a psychotic episode in the context of depression may experience persecutory or self-blaming delusions or hallucinations, while people experiencing a psychotic episode in the context of mania may form grandiose delusions. * schizoaffective disorder, involving symptoms of both schizophrenia and mood disorders * brief psychotic disorder, or acute/transient psychotic disorder * delusional disorder (persistent delusional disorder) * chronic hallucinatory<unk>  Psychotic symptoms may also be seen in: * schizotypal personality disorder * certain personality disorders at times of stress (including paranoid personality disorder, schizoid personality disorder, and borderline personality disorder) * major depressive disorder in its severe form, although it is possible and more likely to have severe depression without<unk>  * bipolar disorder in the manic and mixed episodes of bipolar I disorder and depressive episodes of both bipolar I and bipolar II; however, it is possible to experience such states without psychotic symptoms. * posttraumatic stress disorder * shared delusional disorder * Sometimes in obsessive–compulsive disorder * Dissociative disorders, due to many overlapping symptoms, careful differential diagnosis includes especially dissociative identity disorder. * Eating disorders like anorexia nervosa and bulimia nervosa can cause delusions and even hallucinations of them being "fat" even though they are thin. Psychotic features from eating disorders is most likely to be caused by malnutrition rather than the eating disorder itself. Subtypes Subtypes of<unk>  include: * Menstrual<unk> , including circa-mensual (approximately monthly) periodicity, in rhythm with the menstrual cycle. * Postpartum<unk> , occurring shortly after giving birth * Monothematic delusions * Myxedematous<unk>  * Stimulant<unk>  * Tardive<unk>  * Shared<unk>  Cycloid<unk>  Cycloid<unk>  is typically an acute, self-limiting form of<unk>  with psychotic and mood symptoms that progress from normal to full-blown, usually between a few hours to days, and not related to drug intake or brain injury. While proposed as a distinct entity, clinically separate from schizophrenia and affective disorders, cycloid<unk>  is not formally acknowledged by current ICD or DSM criteria. Its unclear place in psychiatric nosology has likely contributed to the limited scientific investigation and literature on the topic. Postpartum<unk>  Postpartum<unk>  is a rare yet serious and debilitating form of<unk> . Symptoms range from fluctuating moods and insomnia to mood-incongruent delusions related to the individual or the infant. Women experiencing postpartum<unk>  are at increased risk for suicide or infanticide. Many women who experience first-time<unk>  from postpartum often have bipolar disorder, meaning they could experience an increase of psychotic episodes even after postpartum. Medical conditions A very large number of medical conditions can cause<unk> , sometimes called secondary<unk> . Examples include: * disorders causing delirium (toxic<unk> , in which consciousness is disturbed * neurodevelopmental disorders and chromosomal abnormalities, including velocardiofacial syndrome * neurodegenerative disorders, such as Alzheimer's disease, dementia with Lewy bodies, and Parkinson's disease * focal neurological disease, such as stroke, brain tumors, multiple sclerosis, and some forms of epilepsy * malignancy (typically via masses in the brain, paraneoplastic syndromes) * infectious and postinfectious syndromes, including infections causing delirium, viral encephalitis, HIV/AIDS, malaria, syphilis * endocrine disease, such as hypothyroidism, hyperthyroidism, Cushing's syndrome, hypoparathyroidism and hyperparathyroidism; sex hormones also affect psychotic symptoms and sometimes giving birth can provoke<unk> , termed postpartum<unk>  * inborn errors of metabolism, such as Wilson's disease, porphyria, and homocysteinemia. * nutritional deficiency, such as vitamin B12 deficiency * other acquired metabolic disorders, including electrolyte disturbances such as hypocalcemia, hypernatremia, hyponatremia, hypokalemia, hypomagnesemia, hypermagnesemia, hypercalcemia, and hypophosphatemia, but also hypoglycemia, hypoxia, and failure of the liver or kidneys * autoimmune and related disorders, such as systemic lupus erythematosus (lupus, SLE), sarcoidosis, Hashimoto's encephalopathy, anti-NMDA-receptor encephalitis, and non-celiac gluten sensitivity * poisoning, by therapeutic drugs (see below), recreational drugs (see below), and a range of plants, fungi, metals, organic compounds, and a few animal toxins * sleep disorders, such as in narcolepsy (in which REM sleep intrudes into wakefulness) *parasitic diseases, such as neurocysticercosis Psychoactive drugs Various psychoactive substances (both legal and illegal) have been implicated in causing, exacerbating, or precipitating psychotic states or disorders in users, with varying levels of evidence. This may be upon intoxication for a more prolonged period after use, or upon withdrawal. Individuals who experience substance-induced<unk>  tend to have a greater awareness of their<unk>  and tend to have higher levels of suicidal thinking compared to those who have a primary psychotic illness. Drugs commonly alleged to induce psychotic symptoms include alcohol, cannabis, cocaine, amphetamines, cathinones, psychedelic drugs (such as LSD and psilocybin), κ-opioid receptor agonists (such as enadoline and salvinorin A) and NMDA receptor antagonists (such as phencyclidine and ketamine). Caffeine may worsen symptoms in those with schizophrenia and cause<unk>  at very high doses in people without the condition. Cannabis and other illicit recreational drugs are often associated with<unk>  in adolescents and cannabis use before 15 years old may increase the risk of<unk>  in adulthood. Alcohol Approximately three percent of people who are suffering from alcoholism experience<unk>  during acute intoxication or withdrawal. Alcohol related<unk>  may manifest itself through a kindling mechanism. The mechanism of alcohol-related<unk>  is due to the long-term effects of alcohol consumption resulting in distortions to neuronal membranes, gene expression, as well as thiamin deficiency. It is possible that hazardous alcohol use via a kindling mechanism can cause the development of a chronic substance-induced psychotic disorder, i.e. schizophrenia. The effects of an alcohol-related<unk>  include an increased risk of depression and suicide as well as causing psychosocial impairments. Delirium Tremens, a symptom of chronic alcoholism which can appear in the acute withdraw phase, shares many symptoms with alcohol-related<unk>  suggesting a common mechanism. Cannabis According to current studies, cannabis use is associated with increased risk of psychotic disorders, and the more often cannabis is used the more likely a person is to develop a psychotic illness. Furthermore, people with a history of cannabis use develop psychotic symptoms earlier than those who have never used cannabis. Some debate exists regarding the causal relationship between cannabis use and<unk>  with some studies suggesting that cannabis use hastens the onset of<unk>  primarily in those with pre-existing vulnerability. Indeed, cannabis use plays an important role in the development of<unk>  in vulnerable individuals, and cannabis use in adolescence should be discouraged. Some studies indicate that the effects of two active compounds in cannabis, tetrahydrocannabinol (THC) and cannabidiol (CBD), have opposite effects with respect to<unk> . While THC can induce psychotic symptoms in healthy individuals, limited evidence suggests that CBD may have antipsychotic effects. Methamphetamine Methamphetamine induces a<unk>  in 26–46 percent of heavy users. Some of these people develop a long-lasting<unk>  that can persist for longer than six months. Those who have had a short-lived<unk>  from methamphetamine can have a relapse of the methamphetamine<unk>  years later after a stressful event such as severe insomnia or a period of hazardous alcohol use despite
Psychosis
Anti-NMDA receptor encephalitis
Depression 
Dissociative identity disorder
Psychotic depression
Phobia
Depression and Anxiety
Collective depression