Keep psychosis in the differential – seek consultation if there is any doubt. Early detection of psychosis and serious mental illness, more broadly, is complicated by a number of factors:

FIRST, psychotic and psychotic-like symptoms are much more common than psychotic disorders, particularly in children and adolescents. They often require specialized assessment and time to judge their significance as indicators of risk for a future disorder.

SECOND, symptom presentations evolve over time, such that what may at first appear to be an anxiety disorder may eventually emerge as schizophrenia. Similarly, psychotic and psychotic-like experiences may be brief and remitting or intermittent, initially suggesting an imminent acute psychosis or psychotic disorder but with time being better understood as, for instance, panic, OCD, or substance-induced psychosis

THIRD, although there are some very common early symptoms of major psychotic disorders, the early course of schizophrenia and related disorders is quite varied. In most young people, acute psychotic symptoms are preceded by “negative” or “non-specific” symptoms such as amotivation, challenges with attention and learning, and social withdrawal. Only a subset of youth who develop major mental illness experience psychotic symptoms in the absence of negative or non-specific symptoms.

FOURTH, comorbidity should be expected. In addition to assessing “either/or” differentials, clinicians should consider “both/and” possibilities. Young people can have both PTSD and schizophrenia, both OCD and Delusional Disorder, both Cannabis Use Disorder and Bipolar I Disorder. In many cases, one disorder may increase the risk of a subsequent or comorbid disorder.
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​Despite some of these challenges, clinicians should remember that psychotic and psychotic-like symptoms are associated with higher risk for poor functional outcomes, including suicide. Diagnostic ambiguity and uncertainty about future clinical course are part of early detection and are not cause for inaction.

The following questions might be helpful:

• How consistent is the person’s experience with the range of experiences considered typical for a particular disorder?
• Does the individual describe their experiences in ways that suggest some break from a longstanding disorder?
• What is the temporal relationship between different symptom clusters? For instance, do symptoms emerge only in the context of a significant stressor or substance use? Are there inconsistencies over time? Are there any examples of one in the absence of the other?

​Research into early trajectories is ongoing, and as our level of understanding deepens, so will our diagnostic acuity. The following cases highlight some common diagnostic challenges and features relevant to differential diagnosis. Importantly, they serve as examples, not an exhaustive guide; please seek consultation around challenging diagnostic questions. 

Challenging Differential Diagnoses

Inattention/hyperactivity

​Aaron’s step-father brings him in for an appointment at the request of staff at his school, who have reported that 12-year-old Aaron’s behavior is increasingly erratic and disorganized. School staff report that Aaron struggles to stay on topic while talking, jumping around between ideas in ways that do not make sense to others and make it difficult to follow him. Aaron’s school also reports that frequently, his behavior and affect are silly, inappropriate for a given situation, and disruptive to the class. When you ask about any other difficulties, Aaron’s step-father explains that when he tries to help Aaron with his homework, it’s as if he’s not taking in or remembering written material. You’ve known Aaron for several years, and although he’s always been a bit of a spacy kid, he liked to read and had done okay in school. You wonder if he has ADHD that’s only evident now in the context of increasing academic demands. You ask him if he thinks he’d have a harder time this year doing last year’s work and he says yes. He denies substance use or feeling depressed and he is not distracted by a specific stressor, but he feels like his mind isn’t working quite right.

​Challenges with attention and executive functioning such as those seen in Attention Deficit/ Hyperactivity Disorder (ADHD) are very common in psychotic spectrum illnesses. In fact, many individuals who later develop psychotic disorders were diagnosed with ADHD as children. Emerging psychosis should be considered in the differential diagnosis for new or worsening attentional or executive functioning challenges, particularly when a child is presenting for the first time in early or late adolescence or has a family history of psychotic illness. This is particularly important because stimulant prescription in these youth can trigger psychosis. Consultation with a neuropsychologist familiar with the early course of psychotic disorders is recommended for any atypical presentation, new adolescent referral, or child with a family history of psychosis.

Social Anxiety

​While in your office to get her flu shot, 13-year-old Davina mentions that she’s been spending more time alone than she did last semester. When you ask her why that is, she says she’s been feeling really nervous and uncomfortable around people. You encourage her to tell you more about this experience, and Davina says, “I just keep wondering what people are thinking about me, if they think I look stupid or am saying something lame. I’m always worried that I’m going to embarrass myself. I’ve sort of worried like this for a couple of years, but it seems like it’s just getting worse.”

When a young person’s discomfort in social situations is related to concerns that they will be judged, negatively evaluated, or feel ashamed/humiliated, it is most likely best explained by social phobia; here, Davina is nervous around others because she is worried that she will look bad or embarrass herself. If she was feeling unsafe (without an actual threat or source of danger), or felt that others were harboring ill will or intending to harm her, this would raise concern about psychosis or psychosis risk.

Traumatic Stress Response

Last week, Courtney told you she’s been feeling off the last several months, like weird things are happening and she feels distant from herself. When you give her the PQ-16, she checks off that she’s seen things that other people apparently can’t see. You encourage Courtney to tell you more about that experience and she says, “Sometimes I think I see figures that look like people, always men, out of the corner of my eye and wonder if they’re following me. I get really nervous and have to turn and check; I have to make sure I’m alert so no one messes with me.” You ask Courtney to tell you more about when the experience first began, and she says, “It’s been happening ever since a guy took advantage of me after a party last year. But it seems weird that it keeps happening.”

Courtney’s experiences are pretty consistent with hypervigilance and detachment following a traumatic event. Coupled with the fact that this experience began after she was assaulted, Courtney’s presentation is probably best explained as a possible traumatic stress response rather than psychosis risk. However, due to the level of comorbidity between PTSD and psychosis, and the fact that Courtney thinks her own response is “weird,” continued psychosis risk monitoring is indicated.

substance use

Becca, age 17, is brought in by her mother after several incidents of behaving oddly. Her mom describes her laughing inappropriately, talking about seeing dancing shapes in the air in front of her, and asking whether family members were real or imposters. The last time this happened, she ran from the home and her family was unable to locate her for hours. They almost called the police. Although they thought she must have been on some type of drug, Becca denied any drug use, telling them that a kid acting weird doesn’t have to mean she is on drugs.

​When you meet with Becca alone, you ask her to tell you more about these experiences. She says they’re “weird,” and that she gets really confused, but that she’s always back to herself after a few hours. You ask Becca what she makes of these experiences, and she says she’s not sure. You know that Becca’s family strictly prohibits any substance use, so you explain to Becca that there are special laws to protect her privacy around substance use and treatment, and that you will not tell her parents if she is using substances unless her use is extremely dangerous. She discloses that she is smoking marijuana with friends and confirms that every incident her mother reported occurred after smoking for several hours. Further questioning reveals no psychotic-like experiences outside the context of cannabis.

Considering the temporal relationship between her marijuana use and these experiences, Becca’s behavior is consistent with the effects of cannabis. A detailed timeline of use and symptom onset/ occurrence is often necessary to differentiate a psychotic disorder from the effects of substances (such as cannabis) known to elicit psychotic-like symptoms. If psychotic-like symptoms preceded substance use, occur during sufficient periods of abstinence, or linger after the effects of the substance would be expected to remit, a psychotic disorder is more likely. Whenever possible, the young person should be urged and helped to maintain a period of abstinence to see if symptoms remit. Recent research suggests that psychotic-like experiences in the context of cannabis use may be associated with a higher risk for  developing a psychotic disorder. Becca should be counseled that cannabis may be a particularly risky substance for her to use and that her “weird” experiences could progress into something less temporary and more debilitating.

Developmental Concerns

At a recent appointment, Eddie’s grandmother mentioned that he’s been struggling since transitioning to fifth grade last fall. You know he has a history of being socially awkward, making little eye contact, misreading nonverbal cues, talking endlessly about rockets and space, and often ending conversations abruptly if others tried to change the topic. Eddie has been easily overwhelmed by loud noises, bright lights, and sudden change since he was a toddler. He has meltdowns at school when he becomes overstimulated, including yelling and flapping his hands. Since he was an avid reader and did fairly well in classes, he never received special services. According to Eddie’s grandmother, his teachers have reported lately that he’s struggling even more than usual, and that he often talks to himself when upset. When you speak with Eddie about school, he says he doesn’t like people at school because they don’t like rockets. You note, “Your grandmother told me that you seem to be talking to yourself a lot.” He says, “I talk to myself because it makes me feel better.” When you ask, “Do you ever talk to someone or something that no one else knows is there?” He looks at you with a puzzled expression, “No, I just talk to myself.”

Eddie is not actually responding to internal stimuli, but is talking to himself to help with affect regulation. The differential of psychosis and autism spectrum disorder (ASD) and other developmental disorders can be challenging because schizophrenia and related disorders are also neurodevelopmental disorders. Early childhood delays or deficits in the development of social, motor, cognitive, and language skills are not uncommon. However, Eddie’s challenges are very consistent with ASD, exacerbated by age and increased social demands. Whereas new anxiety in social situations and difficulty filtering and tolerating environmental stimuli can be signs of an emerging psychotic disorder, they are also common in ASD. It is important to inquire about psychotic-like experiences when there are marked changes such as those Eddie is experiencing, but in the absence of more specific psychotic thought content or trouble with reality testing, referral to or consultation with a developmental disorder clinic is the best next step.

OBSESSIVE THOUGHTS/Compulsions

After observing an unexplained decline in sleep, mood, and ability to get up for work over your last couple of appointments, you decide to ask Ramon, age 16, to fill out the PQ-16. He endorses feeling like he’s sometimes not in control of his own ideas or thoughts. You ask, “How so?” and Ramon elaborates, “Sometimes I have these bad thoughts and I don’t know why; I know they are just in my own head, but I don’t want to have them and they make me feel a little crazy.” You explain that unwanted thoughts, especially embarrassing ones, are quite common, and ask him if he can be more specific. “These thoughts that I like child porn and am going to become a pedophile and end up making child porn keep popping into my head from nowhere. I keep thinking they are true. It’s horrible. I have to say five prayers in a row before I feel better.” ​

Ramon has intrusive thoughts that he cannot control, but these types of thoughts are consistent with OCD, particularly given that he tries (and is able to) neutralize his anxiety with a repetitive behavior. Importantly, however foreign the thoughts, he knows that they are his own. If Ramon thought that these thoughts were coming from outside himself or his head, or that an external person or force was interfering with his thinking, this would be more consistent with a delusional thought and psychosis. The differential between OCD and psychosis is particularly tricky as people may have no insight in OCD, and having obsessions or OCD is associated with higher risk for psychosis. Obtaining a consultation from an OCD and/or psychosis specialist is advised if there is any concern that a person’s experience is not fully accounted for by OCD.