Severe Early-Onset Conduct Disorder and Pervasive Violence in a Patient with Comorbid Neurodevelopmental Disorders

Chief Complaint and Presenting Problem

The patient was a 13-year-old boy with a past psychiatric history of disruptive mood dysregulation disorder (DMDD) versus oppositional defiant disorder (ODD), attention-deficit/hyperactivity disorder (ADHD), Tourette’s disorder, and autism spectrum disorder (ASD) who was brought to the psychiatric emergency department (ED) involuntarily by police due to worsening aggression and violence towards his family over the past 2 days, including physically attacking his mother immediately before presenting to the ED.

History of Present Illness

The patient’s mother reported that he first exhibited violent behavior at 3 years old, repeatedly hitting his classmates in daycare, which led to his expulsion. Throughout his childhood, he continued to display violence toward others, including punching classmates in school and attacking family members at home. Two years ago, when he was 11 years old, he intentionally pushed his pregnant mother down a flight of stairs during an argument, leading to the loss of her twin pregnancy. The patient was also the subject of two active cases by the Department of Children and Families (DCF) regarding violent incidents toward his stepfather, one of which resulted in a fractured finger, the other in a fractured mandible. Two days before presenting to the psychiatric ED, he repeatedly threatened to kill various family members. He physically attacked his pregnant mother, resulting in another loss of pregnancy.

In addition to his threatening and violent behaviors, his family also described a pattern of deceptive behavior, including lying, stealing valuables from their home, and using credit cards without permission. He also exhibited cruelty to animals. His family had caught him crushing lizards in multiple settings, including at home and while visiting his father. He endorsed particular animosity toward dogs. He reported experiencing significant irritation whenever dogs growled or barked at him, and this feeling had at times resulted in him killing the dogs.

Of note, no history of fire-setting was endorsed by the patient or reported by his family. He denied a history of enuresis; however, his stepfather recalled one recent instance of enuresis occurring several weeks prior to this presentation.

Past Psychiatric History

The patient first saw a psychiatrist when he was 3 years old, after he was expelled from his daycare due to repeated episodes of violence against other children. He was diagnosed with ADHD and ASD. Throughout his youth, he displayed deficits in social communication and interaction across multiple contexts, including social-emotional reciprocity and nonverbal communicative behaviors. His mother did not recall him exhibiting restricted and repetitive behaviors, stereotyped movements, intense preoccupations, or inflexible adherence to routines; however, she did note that he frequently appeared to be significantly distressed when circumstances did not match his expectations. His language, although initially delayed, became fluent, but he struggled with pragmatic aspects of communication, including understanding sarcasm or other nuanced social cues. Cognitive assessments placed him in the average range of intellectual ability, and his ASD was determined to be level 2, requiring substantial support. He began to receive Applied Behavior Analysis (ABA) therapy. Although he received ABA therapy for years, he experienced frequent changes in his therapist due to violent outbursts. His mother reported looking into several other therapy types, including Multisystemic Therapy; however, she was unable to pursue them due to a lack of available providers in their area.

Throughout his childhood, the patient continued to exhibit low frustration tolerance and violent outbursts, which progressed to intentionally causing significant physical harm to others and animals. He was admitted to a local pediatric inpatient psychiatry unit seven times during childhood due to violent and threatening behaviors. His mother reported previous psychotropic trials of clonidine, guanfacine, risperidone, amphetamine salts, and lisdexamfetamine; however, she was unable to provide a clear timeline or specific doses of medications prescribed in the distant past. More recently, he was taking lisdexamfetamine 30 mg daily and risperidone 1 mg at bedtime, which his mother reported was helpful in managing both his outbursts and ADHD symptoms.

Due to issues with insurance, his outpatient psychiatric provider was changed to another facility several weeks before presentation to the psychiatric ED. Lisdexamfetamine was discontinued, and he was instead started on viloxazine 200 mg daily for ADHD to minimize potential adverse effects associated with stimulants. In the following few weeks leading up to his presentation to the ED, he began to exhibit worsening verbal and physical aggression, violence, and threatening behaviors toward his family.

There was no known history of other psychiatric symptoms, including major mood disorders, suicidality, or psychosis.

Developmental History

The patient’s mother did not receive prenatal care until late in her pregnancy with him. She was subjected to domestic violence by his father. She underwent an urgent Cesarean delivery prematurely at 35 weeks when she went to the hospital after being hit in the head by the patient’s father and was found to have preeclampsia.

The patient was born weighing 8 pounds and 1 ounce. He was discharged after a routine 2–3-day hospital course. He experienced delays in language milestones, speaking at 26 months and forming phrases at 48 months, and he received extensive speech therapy until he was 6 years old. There were no delays in his motor milestones or toilet training. While he met early social milestones such as smiling, qualitative differences in social interaction became more apparent as he aged (as detailed in his psychiatric history), consistent with ASD.

Educational History

The patient’s mother reported past attempts at establishing school-based interventions, including a Behavior Intervention Plan focused on de-escalation strategies. However, consistency in staffing and approach was reportedly a challenge due to his disruptive behaviors and the high turnover of school personnel willing to work with him. Despite these efforts, he continued to have violent outbursts. He had a history of physical altercations with teachers and classmates, including an incident in which he broke another student’s arm, resulting in a total of seven suspensions and two expulsions. Because of these disciplinary actions, he attended several local schools, both public and private, throughout his youth.

At the time of his presentation to the psychiatric ED, the patient was attending a public school in the eighth grade. He received special accommodations for ADHD and ASD in all subjects except physical education and language arts. He was passing all of his classes with A’s, B’s, and C’s.

Social History

The patient was born and raised in an urban area in the United States. He was initially raised by both parents; however, his parents divorced when he was a toddler. His mother maintained primary custody (80%), while his father had partial custody (20%). The patient primarily lived with his mother, stepfather, and two sisters.

He had an extensive history of physical and verbal abuse by his biological father, with the first reported incident occurring when he was 10 days old. He presented to the pediatric ED following a domestic violence incident in which his father forcibly detached his umbilical cord stump. There were numerous episodes of physical and verbal abuse and multiple cases involving the DCF related to his father. The patient reported feeling unsafe around his father, recalling a time when his father “almost beat (him) to death.” He also reported that his father taught him “prison skills,” including how to make knives and how to fight with intent to cause harm.

The patient had no known history of substance use. He was not in a romantic relationship and was not sexually active.

Family History

The patient’s father was suspected to have posttraumatic stress disorder (PTSD) from his time serving in the United States Special Operations Command; however, he never received a formal diagnosis. He was a heavy daily alcohol drinker. The patient’s 7-year-old sister has a congenital chromosome 11 abnormality and is diagnosed with ODD, ADHD, and OCD. There was no other known history of psychiatric illness, substance abuse, or suicide attempts in the rest of the patient’s family.

Medical History

The patient had a history of asthma and took montelukast and loratadine daily. His surgical history included circumcision after birth and an adenotonsillectomy during childhood. He had a documented mild allergy to midazolam, although the specific reaction was unclear. There was no known history of seizures, loss of consciousness, or traumatic brain injury. It was unclear if the patient’s vaccinations were up to date.

Mental Status Exam

On initial mental status examination, the patient appeared his stated age and was well-groomed with appropriate hygiene. He was alert and oriented to person, place, time, and situation. He was calm but guarded and evasive during the interview, especially regarding his attack on his mother immediately prior to coming to the ED. He spoke with spontaneous, clear, comprehensible speech of appropriate volume, rate, and prosody. There was no evidence of psychomotor agitation, psychomotor retardation, tics, or other abnormal involuntary movements; however, he was restless during the evaluation. His gait was unremarkable. His mood was irritable, and his affect was generally constricted, although reactive. The thought process was linear and goal-directed. No delusions, preoccupations, obsessions, compulsions, or phobias were elicited. The patient denied any suicidal or homicidal ideation. He denied any perceptual disturbances and did not appear internally preoccupied or responsive to internal stimuli. He exhibited poor insight and poor judgment. The patient spoke fluent English without any obvious language deficits.

Formulation

In summary, the patient was a 13-year-old boy with a history of DMDD versus ODD, ADHD, Tourette’s disorder, and ASD, who was admitted involuntarily to the pediatric inpatient psychiatry unit for aggressive and violent behaviors. Predisposing factors included his diagnosed neurodevelopmental disorders (ASD, ADHD, and Tourette’s disorder), long-standing physical and emotional abuse since infancy, witnessing domestic violence, and a family and personal history of aggression, impulsivity, and violent behaviors. Precipitating factors involved a recent change in outpatient psychiatric care and adjustment to a stable psychotropic regimen. Perpetuating factors included a history of multiple unsuccessful psychotropic medication trials, intermittent episodes of aggression and violence resulting in inpatient psychiatric hospitalizations, and ongoing contact with his biological father and abuser. Protective factors included established outpatient psychiatric follow-up, a stable living environment, and consistent family support.

Diagnoses

Treatment Course

The patient was admitted involuntarily to the pediatric inpatient psychiatry unit from the ED. On admission, his vital signs were stable. Routine labs, including complete metabolic panel, complete blood count, thyroid stimulating hormone, free T4, glycohemoglobin, lipid panel, B12 level, folate level, urinalysis, and urine toxicology, were all within normal limits.

He was admitted with primary diagnoses of DMDD and ODD based on his initial presentation in the ED. Throughout the hospitalization, he minimized attacking his mother despite being informed of the extent of her injuries and medical sequelae and did not show any remorse. A rule-out diagnosis of conduct disorder was added to his diagnoses list and subsequently confirmed, replacing the ODD diagnosis. PTSD was also added as a rule-out diagnosis following his endorsement of extensive physical and emotional trauma, with corroborating collateral from his mother.

On admission, he was restarted on his home risperidone 1 mg at bedtime; lisdexamfetamine 20 mg was ordered but not administered, as it was not on the inpatient pharmacy formulary. Although there was no overt physical aggression or violent behavior during his hospitalization, he expressed aggressive thoughts and desires. Risperidone was increased to 1 mg twice daily, and clonidine 0.05 mg twice daily was started and later increased to 0.1 mg twice daily. Long-acting amphetamine salts, 10 mg once daily, were added to target ADHD symptoms. With this combination, he was less irritable and more appropriately interactive with peers on the unit. Six days after admission, his behavior was deemed stabilized, and he was discharged home with conduct disorder added to his diagnoses list. His discharge medications included risperidone 1 mg twice daily, clonidine 0.1 mg twice daily, and long-acting amphetamine salts 10 mg once daily.

At his postdischarge follow-up appointment 2 days later, his mother reported that he had moments of irritability and verbal outbursts but denied any instances of physical aggression or violent behaviors. He had been adherent to his medications, and his family noted that he appeared calmer than before admission. At the next appointment approximately 2 weeks later, long-acting amphetamine salts were increased to 20 mg daily to better target ADHD symptoms. At his follow-up appointment 3 weeks later, his mother reported significant improvement in attention and concentration but noted worsening temper outbursts. Risperidone was increased to 1 mg in the morning and 2 mg at bedtime for aggression and impulsivity.

His next outpatient follow-up appointment 1 month later was cancelled as he was in the juvenile assessment center (JAC). His mother reported that he was arrested after a physical altercation in which he sent her to the hospital. He has since been lost to follow-up.

Discussion

Conduct disorder is a complex psychiatric condition of childhood and adolescence characterized by a persistent and repetitive pattern of behavior that violates the basic rights of others or major age-appropriate societal norms or rules (American Psychiatric Association, 2022). The prevalence of conduct disorder may range from 2% to 10% of the general population, with a higher incidence in males and typically an onset in late childhood or early adolescence (Loeber et al., 2000; Moffitt et al., 2001). Conduct disorder frequently co-occurs with other psychiatric disorders, most notably ADHD and ODD—often considered to be a developmental precursor—as well as anxiety disorders, depressive disorders, and substance use disorders (Angold et al., 2001). The etiology of conduct disorder is thought to be multifactorial: an interplay of genetic predispositions, neurobiological differences, adverse environmental influences, childhood maltreatment, exposure to violence, peer delinquency, and socioeconomic disadvantage (Aishworiya et al., 2022).

This case report illustrates the convergence of numerous risk factors implicated in the development and severity of conduct disorder. Although transient intermittent aggression may be developmentally normal and can emerge as early as toddlerhood, the precocious onset of the patient’s overtly violent behavior at 3 years old is a particularly salient prognostic indicator associated with more persistent and severe antisocial behavior and raises concern for both immediate safety and long-term prognosis (Moffitt, 1993; Pickard et al., 2018; Soreff et al., 2025). His history is marked by profound and early-onset environmental adversity, including severe physical and emotional abuse by his biological father from infancy, witnessing domestic violence, and his mother experiencing violence during pregnancy leading to premature birth—a factor itself associated with neurodevelopmental vulnerabilities—childhood adverse effects that likely contributed to his violent behaviors, considering the relationship between cumulative trauma increasing both severity and chronicity of aggressive symptoms (Almeida et al., 2024). His extensive family history of psychopathology, including his father’s suspected PTSD and alcohol abuse and his sister’s diagnoses of ODD, ADHD, and OCD, points to a potential genetic loading for psychiatric vulnerability; this, in combination with the patient’s preexisting diagnoses (disruptive mood dysregulation disorder, ADHD, Tourette’s disorder, and ASD), represents a complex constellation of neurodevelopmental and behavioral challenges that frequently co-occur with and may possibly accelerate the trajectory toward conduct disorder (Freeman et al., 2016).

The presence of animal cruelty in the patient’s history warrants discussion in the context of the MacDonald Triad, which historically posited a link between childhood animal cruelty, fire-setting, and persistent enuresis as predictors of later violent behavior (Macdonald, 1963). Although the predictive validity of the MacDonald Triad as a cohesive syndrome is controversial, its components hold differential significance, with animal cruelty as the most concerning indicator (Ascione et al., 2001). The association between childhood animal cruelty and increased risk for interpersonal violence, antisocial personality disorder, and overall severe conduct problems has been consistently and reliably observed (Arluke et al., 1999). The patient’s reported pattern of crushing lizards and killing dogs, coupled with his endorsed animosity and irritation toward them, undoubtedly meets this criterion. Although there was no known history of fire-setting, and enuresis was limited to a single, questionable recent incident, the prominent and repeated acts of animal cruelty may indicate severe underlying pathology and align with the component of the MacDonald Triad most strongly associated with aggression and poor prognosis.

The co-occurrence of ASD with severe behavioral problems, including aggression, violence, and other features of conduct disorder, can present unique diagnostic and therapeutic challenges. ASD itself is not a direct cause of violence; however, certain core features of ASD in the setting of other risk factors can increase the risk or shape the presentation of aggressive behaviors (Im, 2016). In the case of this patient, it is possible that difficulties in social understanding and communication may have led to misinterpretations of social cues, causing frustration and subsequent reactive aggression and violence. His ASD likely compounded the difficulties in emotional regulation and social problem-solving, potentially increasing his predisposition to antisocial influences from his father. Differentiating instrumental aggression of conduct disorder from reactive aggression secondary to ASD-related challenges is critical for effective intervention.

Pharmacological treatment in patients with neurodevelopmental comorbidities may also present unique challenges. In this case, the patient’s reportedly effective regimen of risperidone and lisdexamfetamine reflects a relatively common—albeit complex and seemingly contradictory, due to their opposing dopaminergic actions (antagonism vs. agonism)—strategy for managing comorbid symptoms. Risperidone, a second-generation antipsychotic, is U.S. Food and Drug Administration (FDA)-approved for treating irritability and agitation associated with ASD in pediatric patients and is often used off-label to target the severe aggression and violent behaviors characteristic of conduct disorder. Lisdexamfetamine, a Central Nervous System (CNS) stimulant medication FDA-approved for treatment of ADHD, has been shown to assist with impulsivity (Griffiths et al., 2021). The abrupt discontinuation of lisdexamfetamine and switch to viloxazine, a nonstimulant norepinephrine reuptake inhibitor, likely precipitated the rapid clinical decompensation in an adolescent patient with ASD—a population already more susceptible to medication sensitivity (Aishworiya et al., 2022). While viloxazine is an approved treatment for ADHD, its different mechanism of action and slower onset of effect meant the removal of the established dopaminergic support from lisdexamfetamine, leaving the patient without the immediate impulse control established from chronic stimulant use. This case also highlights the dearth of robust evidence guiding polypharmacy in pediatric patients with comorbid conduct disorder and neurodevelopmental disorders including ASD and ADHD.

There currently exists no effective universal treatment for conduct disorder; the current management approach necessitates a comprehensive, multidisciplinary approach integrating psychiatric care, evidence-based psychotherapies, robust family support, and coordinated school-based interventions (Kazdin, 2010). Pharmacotherapy is primarily aimed at treating comorbid conditions, such as stimulants for ADHD or atypical antipsychotics for aggression (Pringsheim et al., 2015). Evidence-based therapeutic modalities for conduct disorder have limited data demonstrating efficacy. A typical multimodal treatment plan includes incorporation of strategies such as Parent Management Training, Multisystemic Therapy, and Functional Family Therapy (Henggeler et al., 2012). Individual therapies include options such as cognitive behavioral therapy and ABA, although its efficacy for core conduct disorder symptoms is less established than for ASD-specific symptoms. Relatedly, standard conduct disorder treatments may need modification to be more accessible and effective for individuals with ASD. The patient received ABA therapy for years, primarily targeting his ASD symptoms and behaviors, although efficacy was likely limited by frequent changes in therapists due to his violent outbursts. High turnover was also seen in the attempted school-based interventions detailed in his educational history, as school staff were often unwilling to continue working with him after experiencing his aggressive outbursts. Other therapy modalities more targeted toward the patient’s escalating aggression and violent behaviors, including Multisystemic Therapy, were unavailable in his area, highlighting a critical service gap in available treatment options.

The patient’s limited access to alternative therapy options additionally underscores the potential influence of social determinants of health on his trajectory and prognosis. Living in an urban area with disparities in access to specialized pediatric mental health services—particularly those equipped to manage severe, comorbid neurodevelopmental and behavioral disorders—significantly limited the range and stringency of his interventions. His family’s encounter with insurance-related disruptions in care leading to an abrupt change in psychiatric provider and psychotropic medication regimen highlights how systemic socioeconomic factors can destabilize vulnerable youth. While his mother was actively involved in his care, other socioeconomic stressors—compounded by the history of domestic violence and the need to navigate multiple social service systems (including mental health, child protective services, and education)—placed a significant burden on his family’s capacity to consistently implement complex treatment plans. Addressing such systemic barriers is crucial for improved outcomes in such complex cases.

Crucially, proactive and ongoing safety planning is paramount to protect family members and others from aggression, particularly in severe cases like this patient’s (Mishna et al., 2016). This underscores the profound treatment resistance often encountered in severe, early-onset conduct disorder, especially when compounded by extensive trauma and multiple comorbidities. The interruption in his established medication regimen due to insurance issues appears to have significantly contributed to his decompensation, highlighting the critical need for continuity of care.

Structural and functional neuroimaging studies have identified abnormalities in brain regions crucial for emotional regulation, decision-making, and empathy, including the prefrontal cortex (PFC), amygdala, anterior cingulate cortex, and insula (Fairchild et al., 2013). Reduced PFC volume and activity, particularly in the orbitofrontal and ventromedial regions, are thought to contribute to impulsivity, poor judgment, and difficulties in learning from punishment (Blair, 2013). Amygdala dysfunction has been linked to impaired fear conditioning and difficulties in recognizing emotional cues in others, which may underlie reduced empathy and guilt, especially in individuals with callous-unemotional traits (Viding et al., 2008). Imbalances in neurotransmitter systems, including serotonin (implicated in impulsivity and aggression), dopamine (involved in reward processing and sensation-seeking), and norepinephrine, are also believed to play a significant role (Birmaher et al., 2009). Dysregulation of the hypothalamic-pituitary-adrenal axis, sometimes manifesting as a blunted cortisol response to stress, has been observed in some individuals with conduct disorder, potentially contributing to fearlessness and a reduced sensitivity to aversive stimuli (Fairchild et al., 2008).

This case report contributes to the existing literature on the severe end of the conduct disorder spectrum, characterized by early-onset aggression, profound trauma, numerous psychiatric comorbidities, and significant treatment challenges. The patient’s trajectory, culminating in arrest and detention in a JAC despite longitudinal intervention, underscores the limitations of current treatment paradigms for the most entrenched behaviors of conduct disorder, and it highlights the significant impact of severe childhood adversity on long-term behavioral outcomes. It also emphasizes that protective factors—namely, strong family support and continuous longitudinal access to psychiatric and therapeutic services in this patient’s case—may have limited efficacy in the face of overwhelming accumulated risk factors. With this, the case also highlights the urgent need for early identification through screening for individual, familial, and systemic risk factors that perpetuate conduct disorder.

Regulatory Approval and Informed Consent

Our institution does not require ethical or IRB approval for reporting individual cases or case series. Verbal and written assent from the patient and written consent from the patient’s parent and legal guardian were obtained for publication of this case report.