Schizophrenia spectrum disorders: Pathology review

Definitions & Key takeaways

Schizophrenia spectrum disorders refer to a group of mental health conditions characterized by symptoms similar to those seen in schizophrenia, which are positive symptoms like hallucinations, delusions, disorganized speech, and disorganized behavior; negative symptoms such as alogia, affective flattening, avolition, and anhedonia; and cognitive ones - like decreased concentration, disorganized thinking, and poor memory. Schizophrenia is the most common of these disorders, with other conditions being schizotypal personality disorder, delusional disorder, and brief psychotic disorder. Schizophrenia spectrum disorders are typically treated using second-generation antipsychotic medication such as clozapine, but adjuvant therapies include social approaches, cognitive behavioral therapy, and electroconvulsive therapy.

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Case study0:00–1:24

A 32 year old male named Bert is brought to the psychiatric clinic by his concerned mother who thinks that Bert's behavior has changed over the past nine months.
Upon further questioning, Bert's mother reveals that he has been isolating himself and stopped calling or visiting his family and friends.
Bert says that he must stay at home because some aliens have been trying to control his mind on physical examination, Bert appears disheveled, has poor eye contact with others and shows little facial expression.
You decide to order a toxicology screen which comes back negative. Some days later, you see a 52 year old female named Auchi who is brought by her concerned husband to the psychiatric clinic.
Auc's husband explains that she started to act strange two months ago when they were at the funeral of her best friend. Upon further questioning, Auchi explains that the funeral was fake because she saw her best friend watching her from a black sedan.
Additionally, her husband says that every time they come home, Auchi is looking for microphones and cameras throughout the house because she thinks that someone is trying to kill them.
Her husband concludes that except for these non bizarre thoughts. She seems functional for the most part of the day.
Just like with bet, you decide to order a toxicology screen which comes back negative. Ok.
Based on the initial presentation, both bet and Auchi seem to have some form of schizophrenia spectrum disorder. These are a group of conditions including schizophrenia that are characterized by difficulty thinking, clearly making good decisions, distinguishing reality from imagination and behaving appropriately.

Pathology1:24–3:38

Sometimes even to the point where they interfere with day to day activities like working, studying eating and sleeping. Now, the main risk factors for developing a Schizophrenia spectrum disorder seem to include having a family history, experiencing a personal trauma or heavy use of substances and especially cannabis during adolescence and that's actually high yield.
However, the underlying cause is poorly understood for your exams. What you need to remember is that it's related to altered levels of the neurotransmitter, dopamine that affect two out of the four dopamine pathways in the brain.
The mesocortical pathway which helps regulate emotions and the mesolimbic pathway which controls motivation and desire bear in mind that these disorders don't affect the two other dopamine pathways, meaning the nigrostriatal pathway which contains motor neurons that bypass the medullary pyramids to control involuntary movements and coordination and the tuberoinfundibular pathway which releases dopamine to limit the secretion of prolactin.
Another factor that might play a role in the development of schizophrenia spectrum disorders is a loss of the brain's gray matter resulting in ventriculomegaly or enlarged ventricles as well as reduced dendritic branching, disrupting neuronal connections within and between regions of the brain.
Ok. Now, the most high yield schizophrenia spectrum disorders include schizophrenia itself, as well as schizophreniform disorder, brief psychotic disorder, and schizoaffective disorder.
What they all have in common is that they typically present with a few key symptoms that fall into one of three main categories, positive psychotic symptoms, negative psychotic symptoms and cognitive symptoms.
Now, positive psychotic symptoms are those that occur in addition to normal experiences, things that really shouldn't exist like adding pineapple to your pizza.

Positive symptoms3:38–8:39

Remember that these positive symptoms usually result from high levels of dopamine in the mesolimbic pathway and they consist of delusions, hallucinations, disorganized, speech and grossly disorganized or abnormal motor behavior, including catatonia, delusions are false beliefs that the person might feel very strongly about so much so that they won't change their mind even if you give them evidence against it.
And these need to be at odds with the person's cultural or religious beliefs for your exams. Remember that there are several subtypes of delusions including persecutory delusions, which are when individuals falsely believe that they are going to be harmed or harassed by other forces or organizations delusions of reference consist of beliefs that random or innocuous events or gestures and comments from strangers are aimed directly at them.
Like a person believing that a television news anchor is secretly sending messages directly to them. There are also grandiose delusions, which is when individuals believe they have exceptional abilities, like superpowers, wealth or fame, erotomaniac delusions where people may falsely believe that another person is in love with them and jealous delusions, for instance, where individuals believe that their partner is unfaithful.
Other less frequent subtypes of delusions include nihilistic delusions where people think everything is futile and sometimes deny their own existence and somatic delusions which focus on a part of the body that is thought to be diseased or malfunctioning.
For example, people believing they're infected with a parasite. Lastly, there are mixed delusions where two or more subtypes of delusions occur at the same time without one being predominant over the other and unspecified delusions which don't fit the criteria for any of the other subtypes.
Positive symptoms also include hallucinations which are perceptions of something that's not really present. Keep in mind that in schizophrenia spectrum disorders, hallucinations happen without any identifiable external or organic cause like using hallucinogenic substances or having an underlying condition.
Now, another important fact is that the most frequent type of hallucinations is auditory ones which can involve hearing, familiar or unfamiliar voices, sounds or commands.
Remember that auditory hallucinations are more commonly linked with psychiatric conditions and especially schizophrenia spectrum disorders than identifiable causes less frequently.
Schizophrenia, spectrum disorders can also present with visual hallucinations where people see things that don't exist as well as tactile olfactory or gustatory hallucinations, which refer to a false perception of touch, smell or taste respectively.
Finally, there are hypnagogic hallucinations which occur right before falling asleep. And hypnopompic hallucinations which occur while waking up.
What you need to know about these is that they are rare enough that their presence raises suspicion for an underlying identifiable cause rather than a schizophrenia spectrum disorder.
So in a test question, visual hallucinations should make you think of substance intoxication or delirium. On the other hand, tactile hallucinations are often seen with alcohol withdrawal and using stimulants like cocaine, olfactory and gustatory hallucinations are commonly associated with temporal lobe epilepsy or brain tumors.
Finally keep in mind that both hypnagogic and hypnopompic hallucinations are often associated with narcolepsy. Another positive symptom is disorganized speech and it's when individuals hop from one conversation topic to another with no connection or loose associations.
Sometimes the speech is so severely disorganized that it is nearly incomprehensible, which seems like just a random jumbling of disconnected words like pencil dog, hat, coffee blue.
And that's often called a word salad, grossly disorganized or abnormal motor behavior is the last positive symptom. And it refers to unusual bizarre or silly behavior that's out of context and doesn't seem to have much of a purpose.
Like for example, wearing multiple layers of jackets on a hot summer day or engaging in repeated purposeless movements or postures.
One extreme is catatonic behavior where the individual becomes very unreactive to their environment. So like they might be in an unresponsive stupor or be super resistant to moving and maintain a bizarre body posture, like a twisted limb, moving on negative psychotic symptoms represent the absence of normal behavior and are caused by low levels of dopamine in the mesocortical pathway.

Negative symptoms8:39–9:49

The most characteristic one is flat affect, which basically means that there's diminished emotional expression. Flat affect can manifest as decreased facial expressions, like smiling or frowning and reduced eye contact as well as decreased speech intonation and a decrease in limb movements that normally help give emotional emphasis to speech.
This can be associated with alogia which means poverty of speech. So when a person chooses not to speak or uses very few words.
For instance, when asked, do you have any Children? They might just respond with a brief and concrete.
Yes, instead of a more spontaneous. Yes, one girl and two boys.
Other examples of negative symptoms include avolition, which is when individuals show decreased motivation or interest in activities, like get togethers hobbies or work as well as asociality, which refers to decreased interest in social interactions and anhedonia which is decreased enjoyment from pleasurable activities.
Finally, schizophrenia spectrum disorder can present with cognitive symptoms which include things like experiencing difficulty understanding others, not being able to process information as quickly and having issues with working memory which involves learning and retaining new information.

Cognitive symptoms9:49–10:07

Ok. Then let's start with schizophrenia.
This is the most common of these disorders and affects 0.3% to 0.7% of the general population over a lifetime. Another thing to note is that it tends to present earlier in males, typically in the early to mid twenties while in females, it most commonly shows up in the late twenties.

Schizophrenia10:07–11:30

Now, for an official diagnosis of schizophrenia, individuals need to present with at least two of the following symptoms that must occur during a one month period, delusions, hallucinations, disorganized speech, disorganized or catatonic behavior or negative symptoms.
Furthermore, remember that at least one of the symptoms has to be either delusions, hallucinations or disorganized speech.
Besides the one month period that meets the full criteria. Some symptoms should stick around for a period of at least six months, either before the one month period when they're called prodromal symptoms or after the one month period when they're called residual symptoms.
Some individuals can present with additional symptoms that don't fit into these categories such as hostility and aggression as well as a lot of anxiety.
What's important to keep in mind is that these individuals also have an increased risk of suicide. Then there's schizophreniform disorder which causes the exact same symptoms as in schizophrenia.
But for more than one month and less than six months, next, there's brief psychotic disorder where at least one of the following positive symptoms is present among delusions, hallucinations, disorganized speech and disorganized or catatonic behavior.

Schizophreniform disorder11:30–11:43

Brief psychotic disorder11:43–12:14

Also, at least one of the symptoms should be delusions, hallucinations or disorganized speech additionally, what sets it apart from schizophrenia is that these should last longer than a day but less than a month.
Another thing to note is that brief psychotic disorder can occasionally have a specific cause or trigger such as experiencing a traumatic event or childbirth.
Moving on to delusional disorder. This is diagnosed when one or more delusions are present for at least a month without meeting the criteria for schizophrenia.

Schizotypal personality disorder12:14–13:43

Hallucinations may also be present but they're not predominant and are usually limited to the delusion. For example, if individuals believe that they had organs removed while sleeping, they might feel pain or a sensation of emptiness.
The most important thing to keep in mind is that delusions in this disorder are typically non bizarre, meaning that even though they are not true, they could be feasible in the right circumstances.
On the other hand, keep in mind that a bizarre delusion is one that defies the laws of physics such as believing that they have superpowers and typically points towards schizophrenia.
Based on the main delusional theme that a person is experiencing. Delusional disorder can be subdivided into seven types, persecutory, grandiose, erotomanic, somatic jealous, mixed and unspecified.
Another high yield difference is that individuals with delusional disorder typically don't exhibit negative or cognitive symptoms and remain functional for the most part except for the delusion itself.
Next, there is schizoaffective disorder where affected individuals present with both psychotic symptoms as well as a major mood episode such as a major depressive or manic episode.
This makes this condition hard to tell apart from primary mood disorders such as major depression or bipolar disorders that can be complicated by psychotic features.

Delusional disorder13:43–14:42

On a test question, you should think of schizoaffective disorder if the individual presents with psychotic symptoms like delusions and hallucinations for at least two weeks outside of a mood episode.
On the other hand, if the psychotic symptoms only occur during a mood episode, you should think of a primary mood disorder with psychotic features and that's a high yield fact.
Finally, there's schizotypal personality disorder, which is classified in the DSM five under cluster A personality disorders.
Now, the reason it's also included with the Schizophrenia spectrum disorders is that it's characterized by mild negative symptoms such as inappropriate or flat affect as well as mild positive symptoms such as odd thinking and speech.
Individuals with schizotypal personality disorder also typically come across as being quirky or eccentric. Many dress up in peculiar ways like wearing shorts or boxers on top of their jeans.

Schizoaffective disorder14:42–15:32

In addition, individuals with schizotypal personality disorder tend to be socially awkward and have a reduced capacity for close relationships.
However, they often have a strong desire to have them but are often unable to maintain them. Individuals with schizotypal personality disorder may also have ideas of reference which are false beliefs that real and irrelevant occurrences directly relate to them, like thinking that it's raining because the world is sending them a specific signal.
Similarly, these individuals can be overly superstitious or might engage in magical thinking like believing in clairvoyance or telepathy as well as having paranormal beliefs.
The most important thing to keep in mind here is that individuals with schizotypal personality disorder typically do not exhibit frank delusions or hallucinations, which sets it apart from schizophrenia.

Treatment15:32–19:28

Now, treating schizophrenia spectrum disorders can be very challenging, but there are a few different approaches. First, there are antipsychotic medications which can be subdivided into two main categories.
First generation or typical antipsychotics and second generation or atypical antipsychotics. First generation or typical antipsychotics include haloperidol, trifluoperazine, fluPHENAZine, thioridazine, chlorproMAZINE and thiothixine which block dopamine D2 receptors in the mesolimbic pathway, thereby alleviating positive symptoms.
However, keep in mind that they can also block dopamine receptors in the mesocortical pathway, which might actually worsen the negative symptoms.
And that's extremely high yield in terms of side effects in the tuberoinfundibular pathway. Typical antipsychotics, block dopamine D2 receptors, thereby increasing the release of prolactin causing oligomenorrhea or infrequent menstrual periods, gal, lactorrhea, or inappropriate milky nipple discharge and gynecomastia or abnormal breast enlargement.
On the other hand, in the nigrostriatal pathway, they may cause extrapyramidal symptoms which typically involve abnormal movements such as dystonia or involuntary muscle spasms.
Most often involving the tongue, face, neck and back as well as a which is an urge to move the limbs. Pseudoparkinsonism, which is characterized by muscle rigidity, bradykinesia or slow movements and tremors and lastly tardive dyskinesia which involves constant involuntary rhythmic movements.
On the other hand, the newer second generation or atypical antipsychotics include a copine cloZAPine, OLANZapine, and QUEtiapine, as well as iloperidone polyone risperiDONE Fluzone and Cipra zid atypical antipsychotics work by blocking dopamine D2 receptors in the mesolimbic pathway, thereby alleviating positive symptoms.
But what's important is that they also block serotonin five HT two A receptors in the mesocortical pathway. These receptors are generally found on inhibitory neurons that normally regulate dopaminergic neurons and decrease dopamine release when atypical antipsychotics block the serotonin five ht two A receptors on these inhibitory neurons, dopaminergic neurons have no inhibitory signals.
So, dopamine release actually increases in the mesocortical pathway. Thus, atypical antipsychotics can also help alleviate the negative symptoms, which makes them the preferred medication over typical antipsychotics.
On top of that, atypical antipsychotics are associated with fewer extrapyramidal side effects. But keep in mind that they do tend to have metabolic side effects such as weight gain hyperlipidemia and diabetes mellitus, which may ultimately increase the risk of cardiovascular disease.
Now, except for antipsychotics, remember that in conditions such as schizoaffective disorder that may cause mood episodes, antidepressant medications and mood stabilizers can also be used.
In addition to medications, individuals with schizophrenia spectrum disorders can benefit from psychotherapy including cognitive behavioral therapy or CBT for short.
This is a type of talk therapy that primarily focuses on teaching the individual strategies to challenge their negative thoughts, feelings and behavior patterns.
Finally, there's also increasing evidence that exercising, yoga, meditation, and listening to music can help improve symptoms associated with schizophrenia, spectrum disorders, both as a coping mechanism and a distraction.

Review19:28–21:13

All right. As a quick recap, schizophrenia, spectrum disorders are characterized by positive psychotic symptoms, like hallucinations, delusions, disorganized, speech, disorganized or catatonic behavior, as well as negative psychotic symptoms such as flat affect alogia abolition, asociality and anhedonia and cognitive symptoms.
Like difficulty understanding others or processing information as quickly and having issues with working memory. To diagnose schizophrenia, there should be at least two symptoms lasting for a full month and at least one of them has to be hallucinations, delusions or disorganized speech.
Schizophrenia also requires the presence of prodromal or residual symptoms for at least six months. Next, schizophreniform disorder has all the symptoms of schizophrenia, but they last for more than one but less than six months.
On the other hand, in brief psychotic disorder, the psychotic symptoms last from one day to a month. Delusional disorder is characterized by non bizarre delusions for at least a month.
Based on the main delusional theme that a person is experiencing. Delusional disorder can be subdivided into seven types, persecutory, grandiose, erotomanic somatic jealous, mixed and unspecified.
Next, schizoaffective disorder features a combination of psychotic symptoms which are predominant and can be accompanied by mood episodes.
Finally, schizotypal personality disorder, which is classified in the DSM five under cluster A personality disorders features, mild negative symptoms such as flat affect, as well as mild positive symptoms such as odd behaviors, perceptions and beliefs, as well as magical thinking without frank delusions or hallucinations and difficulties in maintaining close relationships.

Summary21:13–22:49

Schizophrenia, spectrum disorders are typically treated using second generation or atypical antipsychotic medications, which can be combined with cognitive behavioral therapy.
Ok. Back to our cases.
Bet is a 32 year old male that has recently exhibited social withdrawal. This along with his disheveled appearance, the poor eye contact and lack of facial expression found on physical examinations, all point to negative symptoms of a schizophrenia spectrum disorder.
At the same time, Bert believes that aliens are trying to control his mind, which is a form of persecutory delusion and thus a positive symptom of a schizophrenia spectrum disorder.
And since these symptoms have lasted longer than six months, we can conclude it's schizophrenia after birth. You see 52 year old Auchi who believes that someone is trying to kill her and her husband notice that Auchi is experiencing non bizarre delusions, meaning that even though they are not true, they could be feasible in the right circumstances.
Another high yield thing to keep in mind is that Auchi does not exhibit negative or cognitive symptoms and remains functional for the most part.
And since these symptoms have lasted for more than a month, we can conclude that Auchi is experiencing a delusional disorder.