Neurodevelopmental, schizophrenic, depressive disorders

For AP Psychology, you need to understand several major psychological disorders. In this course, these disorders will be grouped into a few sections. For each disorder, focus on two things:

• The symptoms (what you would observe)
• The possible causes (what might contribute to the disorder)

Neurodevelopmental disorders

Neurodevelopmental disorders are conditions that involve impaired brain development. This impairment affects emotional, social, and cognitive functioning and can interfere with daily life.

These disorders usually become noticeable early in life, often before children enter school. They reflect atypical brain development that can affect thinking, social skills, language, or movement. Some people improve over time, but challenges may continue into later stages of life.

In AP Psychology, there are two key neurodevelopmental disorders: Attention-Deficit/Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD).

Attention-deficit/hyperactivity disorder (ADHD)

ADHD is marked by persistent difficulties with attention, excessive activity, or impulsive behavior that is not appropriate for a person’s developmental level. To meet the definition of a disorder, these symptoms must be strong enough to disrupt learning, social interactions, or routine tasks.

ADHD symptoms fall into two domains:

• Inattention: Trouble sustaining focus, missing details, appearing unresponsive when addressed, frequently losing items, and difficulty following complex instructions.
• Hyperactivity-impulsivity: Constant movement or restlessness, inability to remain seated, excessive talking, acting without thinking, interrupting others, blurting out answers prematurely, and difficulty waiting one’s turn.

Based on which domain’s symptoms are most prominent, ADHD is classified into three presentations:

• Predominantly inattentive: Attention issues are most prominent.
• Predominantly hyperactive-impulsive: Hyperactivity and impulsivity dominate.
• Combined: Significant symptoms from both domains are present.

Autism spectrum disorder (ASD)

ASD involves challenges in social communication, restrictive or repetitive behaviors, or learning. Because symptoms and severity vary widely - and because the challenges affect different people in different ways - ASD is described as a “spectrum” rather than a single, uniform diagnosis. Symptoms typically appear early but may become more noticeable as social demands increase.

Characteristic signs may include:

• Difficulty engaging in back-and-forth conversation and sharing emotions.
• Trouble forming friendships appropriate for their age.
• Limited eye contact, gestures, and facial expressions.
• Repetitive movements like rocking or hand-flapping.
• Strong preference for routine and distress over minor changes.
• Sensitivity to sensory inputs such as loud noises or touch.

Possible causes of neurodevelopmental disorders

These conditions often arise from a mix of genetic and environmental factors such as:

• Genetics: Studies of families and twins reveal strong hereditary links.
• Physiology: ADHD is connected to differences in the prefrontal cortex and dopamine activity, while ASD shows atypical brain connectivity and early brain growth.
• Environmental elements: Exposure to toxins before birth, insufficient nutrients during pregnancy, premature birth, or infections during pregnancy can raise risk.

Schizophrenic spectrum disorders

Schizophrenic spectrum disorders involve disruptions in thinking, emotions, behavior, and perception of reality. Symptoms usually appear in late adolescence or early adulthood, sometimes with subtle early warning signs.

Symptoms can develop quickly or gradually, so schizophrenia is sometimes described as either:

• Acute schizophrenia: Rapid onset, often connected to major stress.
• Chronic schizophrenia: Gradual development with lasting symptoms, often leading to greater impairment.

Common misconception: Schizophrenia is not the same as dissociative identity disorder (DID). Schizophrenia is a psychotic disorder involving breaks from reality (hallucinations, delusions), not a disorder of multiple personalities. The College Board explicitly tests this distinction.

The DSM-5 identifies five key symptoms of schizophrenic spectrum disorders. The first four are positive symptoms (unusual experiences or behaviors added on top of normal functioning); the fifth describes negative symptoms (reductions in typical behavior or emotional response):

• Delusions (positive): Firmly held false beliefs, such as:
  • Delusions of persecution: Believing others intend to cause harm.
  • Delusions of grandeur: Believing in exceptional powers or influence.
• Hallucinations (positive): Sensory experiences without external stimuli (such as hearing voices that are not there). This can involve one or more of the senses.
• Disorganized thinking or speech (positive): Abrupt topic shifts, incoherent speech, sometimes described as “word salad” (putting words together in a noncoherent way).
• Grossly disorganized or abnormal motor behavior (positive): Erratic movements, inappropriate silliness, or unresponsiveness. One example is catatonia - a state of disordered movement that can appear as stupor (greatly reduced responsiveness) or as agitated, purposeless excitement.
• Negative symptoms: A reduction in typical behaviors or emotional responses. Examples include flat affect (reduced emotional expression), avolition (loss of motivation), and catatonic stupor.

Like many conditions, multiple factors could contribute to the development of schizophrenic spectrum disorders, such as:

• Genetic: Increased prevalence among identical twins supports hereditary factors of these conditions.
• Biological: Imbalanced dopamine pathways are linked to positive symptoms, while underactive dopamine function relates to negative symptoms (dopamine hypothesis). Also, prenatal viral exposure has also been linked to increased risk.

How do neurodevelopmental disorders differ from schizophrenic spectrum disorders in terms of when symptoms typically appear?

Depressive disorders

Depressive disorders involve long-lasting mood disturbances (such as feeling sad, empty, or irritable), loss of interest, and physical or cognitive changes. These symptoms affect daily functioning, including a person’s work, educational, or social life.

AP Psychology focuses on two conditions within this category: Major Depressive Disorder (MDD) and Persistent Depressive Disorder (PDD).

Major depressive disorder (MDD)

MDD is characterized by at least two weeks of persistent sadness, hopelessness, and anhedonia (the loss of pleasure or interest in activities previously enjoyed).

Don’t confuse ordinary sadness with MDD. Feeling sad after a difficult event is a normal emotional response. MDD requires symptoms lasting at least two weeks that significantly impair daily functioning - the duration and impairment threshold are what distinguish a disorder from a temporary low mood.

Other common signs include:

• Noticeable weight or appetite changes.
• Sleep disturbances: either insomnia or excessive sleeping.
• Motor changes: either slowing down or agitation.
• Chronic fatigue or loss of energy.
• Excessive guilt or worthlessness.
• Difficulty concentrating or making decisions.
• Thoughts of death or suicide.

Persistent depressive disorder (PDD)

PDD is a chronic depression lasting two years or more in adults (one year for children and teens). Symptoms are generally less severe than in MDD, but they last longer.

Symptoms can involve:

• Ongoing low mood or irritability.
• Poor or excessive appetite.
• Sleeping problems.
• Low energy and fatigue.
• Low self-esteem.
• Trouble concentrating or deciding.
• Feelings of hopelessness.

MDD vs. PDD: The key distinction is severity versus duration. MDD involves more severe symptoms but requires only two weeks. PDD involves milder symptoms that persist for two or more years. A person can experience both simultaneously - sometimes called “double depression.”

Possible causes of depressive disorders

Depression is best explained using multiple perspectives:

• Biological: Imbalanced neurotransmitters (like serotonin, norepinephrine, and dopamine) have been linked to mood regulation. Other biological imbalances (such as with hormones, digestion, inflammation, and nutrition) have also been linked with depressive disorders.
• Genetic: Family history indicates a possible inherited risk.
• Social/cultural: Ongoing stress, isolation, discrimination, and poverty increase susceptibility. Cultural norms could also affect symptom expression and help-seeking.
• Behavioral: Lack of positive reinforcement from surroundings can foster withdrawal and inactivity.
• Cognitive: Negative thought cycles, hopelessness, and rumination could perpetuate symptoms. Cognitive distortions, like overgeneralizing from single events, could maintain depression.

What are the main differences in symptoms between depressive disorders and schizophrenic spectrum disorders?