schizophrenia & autism

• characterized social withdrawal, disorganized thinking, abnormal speech, and an inability to understand reality. • The prevalence is nearly 1% of world’s population. (fairly common) • Symptoms typically come on gradually, begin in young adulthood, and in many cases never resolve (although 20% of people eventually do quite well). no obvious symptoms for the first 20 years • About 30-50% of people with schizophrenia do not believe they have an illness or comply with their recommended treatment.

true

• Negative: the absence of behaviours - social withdrawal, reduced emotional expression, poverty of speech, and reduced motivation • Cognitive: disorganized and irrational thinking, deficits in learning and memory, poor abstract thinking, and poor problem solving • Positive: the presence of delusions (delusions of persecution, grandeur, or control - beliefs that contradict reality) and hallucinations (perception of stimuli that are not actually present) • they think people are out to get them, they are persecuted. grandeur: they have a special ability, more power and unique than the average people. control: they ca control things that they obviously cant, or other people cant (the weather example)

1) negative symptoms 2) cognitive symptoms 3) years later, positive symptoms

• poor control of eye movements • unusual facial expressions. • subtle differences in brain structure, but these are quite variable. • more quirks than the usual people • weird facial expressions or eye movements, • not a clearly specific quirk is associated with schizophrenia.

Schizophrenia is primarily a genetic disorder. * 5% of cases are caused by rare gene copy number variations (duplicated or missing genes), which often result in schizophrenia comorbid with autism and intellectual disabilities. These highly penetrant gene mutations are rare, even among people with schizophrenia. (penetrant: rare very harmful genes mutations) • Most cases of schizophrenia seem to relate to unfortunate combinations of common but slightly harmful gene mutations.

– the mother’s nutrition and level of stress during pregnancy – infections the mother gets during pregnancy – complications during the birthing process (hypoxia) – childhood trauma and social isolation – birth month and being raised in a city

The month a person is born has a tiny influence on their risk of developing schizophrenia. If no one was born between the months of February and May, the prevalence of schizophrenia would decrease by about 3%. Rates of schizophrenia are also slightly higher in urban versus rural environments. Presumably, some seasonal infection that is more common in dense cities affects embryonic brain development.

Symptoms of schizophrenia are not normally seen in childhood, but… * Children who go on to develop schizophrenia often display less sociability and deficient psychomotor functioning as kids. * Minor physical abnormalities are often seen in children who go on to develop schizophrenia, such as partial webbing of the two middle toes and a high-steepled palate

false, there is none.

The main treatment is medication, often in combination with psychological and social support. * Many drugs have been developed that alleviate some of the symptoms of schizophrenia. They, in part, block dopamine D2 receptors and are called antipsychotics or neuroleptics. * This makes sense because dopamine receptor agonists, like crystal meth and cocaine, can temporarily elicit some of the symptoms of schizophrenia in people who do not have the disorder.

excessive dopamine D2 receptor activity, particularly in the nucleus accumbens, underlies the positive symptoms of schizophrenia. In living people we don’t know exactly how much dopamine there is in the brain, so this is just an hypothesis. The dopamine neurons are maybe too active.

false. While dopamine D2 receptor antagonists can reduce the positive symptoms of schizophrenia (the delusions and hallucinations), they don’t effectively treat the negative symptoms (i.e., the reductions in motivation, speech, emotionality, and sociality). The negative symptoms of schizophrenia account for a large part of the long-term disability and poor functional outcomes.

Positive symptoms may relate to excess dopamine signaling in the nucleus accumbens, whereas negative symptoms may relate to insufficient dopamine signaling in the PFC (prefrontal cortex). Clozapine has been found (in monkeys) to simultaneously decrease dopamine levels in the nucleus accumbens and increase dopamine levels in the prefrontal cortex.

Some evidence suggests that the negative symptoms relate to hypofrontality – reduced neural activity in the prefrontal cortex. – Schizophrenics do poorly on neuropsychological tests that are sensitive to prefrontal brain damage. – And people with prefrontal damage exhibit some of the negative symptoms of schizophrenia. Hypofrontality may relate to insufficient dopamine D1 receptor activity in the PFC.

they were designed to influence the activity of several neurotransmitter receptors (beyond blocking dopamine D2 receptors). The rationale behind their development was that dopamine D2 receptor antagonists are pretty good, but they have many side effects and don’t address the negative symptoms. Maybe a dirty drug that affects many receptors could simultaneously reduce the positive and negative symptoms of schizophrenia with minimal side effects.

Clozapine is a dirty drug, which means it alters the activity of several different types of receptors. It primarily blocks dopamine D2 receptors and serotonin 2A receptors. It was the first of the atypical antipsychotic medications.

Aripiprazole (also known as Abilify) is another atypical antipsychotic. It is thought to simultaneously reduce dopamine receptor activity in the nucleus accumbens while boosting it in the prefrontal cortex. This is because it is a partial agonist at some dopamine receptors (and some serotonin receptors).

a drug with very high affinity for a receptor, but it activates it less than the normal ligand does. Because of these properties, a partial agonist can boost receptor activity in regions where there is low concentration of the normal ligand while simultaneously reducing receptor activity in regions where there is high concentration of the normal ligand.

true, they can be temporary or episodic examples: depression, anxiety, PTSD, eating disorders, drug addiction

true. example: autism, ADHD, intellectual disability, Tourette’s syndrome

true, examples: schizophrenia, bipolar disorder, OCD

• Anxiety disorders, major depression, PTSD, and OCD are nearly 2 times more common in females. • Anorexia is 3 times more common in females. • Bulimia is 10 times more common in females.

• Intellectual disability is 2 times more common in males. • Tourette’s syndrome is 3 times more common in males. • Autism and ADHD are 4 times more common males.