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Autism Spectrum Disorder: Expert Psychiatrist Guide to Diagnosis and Treatment

By Ryan S. Sultan, MD
Assistant Professor of Clinical Psychiatry, Columbia University Irving Medical Center
Board-Certified in Adult Psychiatry and Child & Adolescent Psychiatry
March 29, 2026

What Is Autism Spectrum Disorder?

Autism spectrum disorder (ASD) is defined by two core domains of difference, both of which must be present for diagnosis.

Domain 1: Social Communication and Interaction

Autistic individuals experience persistent differences in social communication and social interaction across multiple contexts. These include deficits in social-emotional reciprocity (difficulty with back-and-forth conversation, reduced sharing of interests or emotions, difficulty initiating or responding to social interactions), deficits in nonverbal communication (atypical eye contact, facial expressions, body language, gestures; difficulty integrating verbal and nonverbal communication), and deficits in developing, maintaining, and understanding relationships (difficulty adjusting behavior to different social contexts, difficulty sharing imaginative play, reduced interest in peers or difficulty making friends).

It is important to understand that these are not deficits in the ability to connect or care about others. Many autistic individuals deeply desire social connection but find the implicit, unwritten rules of social interaction confusing, exhausting, or opaque. The social world operates on a set of unspoken conventions that neurotypical people absorb intuitively -- autistic individuals must learn these rules explicitly, which is cognitively demanding and often incomplete.

Domain 2: Restricted, Repetitive Patterns of Behavior, Interests, or Activities

At least two of the following must be present: stereotyped or repetitive motor movements, speech, or use of objects (hand flapping, echolalia, lining up toys, spinning); insistence on sameness, inflexible adherence to routines, ritualized patterns (distress at small changes, rigid thinking, greeting rituals, need to take the same route); highly restricted, fixated interests that are abnormal in intensity or focus (strong attachment to unusual objects, excessively circumscribed interests); and hyper- or hypo-reactivity to sensory input or unusual interest in sensory aspects of the environment (apparent indifference to pain or temperature, adverse response to specific sounds or textures, excessive touching or smelling of objects, fascination with lights or spinning objects).

DSM-5 Severity Levels

Adult Autism Diagnosis: The Growing Recognition

One of the most significant developments in autism understanding over the past decade has been the recognition that many autistic adults were never diagnosed in childhood. This is particularly true for individuals who are verbally fluent and intellectually capable (previously called "Asperger syndrome," now folded into ASD Level 1), women and girls (who tend to mask more effectively and present differently from the historically male-dominated diagnostic profiles), individuals from racial and ethnic minority backgrounds (where diagnostic access has historically been limited), and people born before autism awareness became widespread.

The path to adult autism diagnosis often looks like this: the person has always felt "different" from peers but could not articulate why. They may have developed effective compensatory strategies (masking) that allowed them to function socially and professionally, but at enormous personal cost. They may have been previously diagnosed with social anxiety, depression, ADHD, or a personality disorder -- all of which may be partial explanations but miss the underlying autism. Eventually, they encounter information about autism (often through the experiences of others) and realize it describes their lifelong experience.

Masking and Its Consequences

Masking (also called camouflaging) deserves particular attention because it explains why so many autistic adults go undiagnosed and because sustained masking has significant mental health consequences.

What masking involves:

• Studying and mimicking others' facial expressions, gestures, and social behaviors
• Preparing scripts and rehearsing conversations in advance
• Suppressing stimming behaviors (rocking, hand flapping, fidgeting)
• Forcing eye contact despite it being uncomfortable or overwhelming
• Hiding or downplaying intense interests to appear "normal"
• Developing a social "persona" that differs from their authentic self
• Monitoring and analyzing social situations in real-time, which is cognitively exhausting

The cost of masking: Chronic masking is associated with autistic burnout (complete exhaustion of coping capacity), increased rates of anxiety and depression, identity confusion ("Who am I without the mask?"), suicidal ideation (autistic individuals have significantly elevated suicide risk, and masking appears to be a contributing factor), physical exhaustion (the cognitive load of constant self-monitoring), and delayed diagnosis (if the mask is effective enough, clinicians do not see the underlying autism).

Autism vs. ADHD: Overlap and Distinction

The overlap between autism and ADHD is substantial and clinically important. Research suggests that 30-50% of autistic individuals also meet criteria for ADHD, and since the DSM-5 (2013), both diagnoses can be given simultaneously.

For a comprehensive discussion, see my guide on ADHD vs. Autism: How to Tell the Difference.

Co-Occurring Conditions: The Primary Focus of Psychiatric Treatment

Approximately 70% of autistic individuals have at least one co-occurring psychiatric condition, and 40% have two or more. These comorbidities often cause more day-to-day impairment than the core autism features and are the primary target of psychiatric treatment.

Anxiety disorders (40-50%): The most common co-occurring condition. Social anxiety is particularly prevalent, but generalized anxiety, specific phobias, and separation anxiety are also common. Treatment involves modified CBT (adapted for autism, with more concrete, structured approaches and visual supports) and SSRIs (starting at lower doses, as autistic individuals may be more sensitive to medication effects).

ADHD (30-50%): Stimulant medications are effective for ADHD in autistic individuals, though response rates may be slightly lower and side effects (irritability, social withdrawal) may be more common than in non-autistic ADHD. Non-stimulant alternatives (guanfacine, atomoxetine) are useful options.

Depression (20-40%): Often related to social isolation, masking exhaustion, bullying, and lack of accommodation. SSRIs are the first-line pharmacological treatment, combined with adapted therapy approaches.

OCD (17-37%): The overlap between OCD-like symptoms (rituals, insistence on sameness, repetitive behaviors) and autism's restricted/repetitive behavior domain can make diagnosis challenging. True comorbid OCD involves ego-dystonic obsessions and compulsions, while autism-related repetitive behaviors are often ego-syntonic (enjoyable or comforting). When true OCD co-occurs, ERP and SSRIs are effective. See OCD Treatment NYC.

Sleep disorders (50-80%): Insomnia is extremely common in autism, often related to melatonin production differences, anxiety, and sensory sensitivities. Melatonin (0.5-5 mg) is the first-line treatment, with evidence specifically in autistic populations.

Irritability and aggression: Risperidone (Risperdal) and aripiprazole (Abilify) are the only medications FDA-approved specifically for irritability associated with autism in children and adolescents. These should be used judiciously, with appropriate metabolic monitoring, and only after behavioral interventions have been attempted.

The Role of Medication in Autism

To be clear: there is no medication that treats the core features of autism. No medication will fundamentally change social communication patterns or eliminate restricted/repetitive behaviors. Claims to the contrary are not supported by evidence.

What medication can do is treat the co-occurring conditions that cause significant distress and impairment. When an autistic person's severe anxiety prevents them from leaving the house, an SSRI can reduce that anxiety enough to allow them to engage with the world. When ADHD prevents them from completing tasks at work, a stimulant can improve focus and executive function. When irritability and aggression are destroying relationships, a low-dose antipsychotic can reduce emotional reactivity.

Important prescribing considerations for autistic individuals:

• Start lower, go slower: Many autistic individuals are more sensitive to medication side effects. I typically start at half the usual starting dose and titrate more gradually.
• Monitor carefully: Side effects like activation (increased agitation from SSRIs), appetite changes (stimulants), and metabolic effects (antipsychotics) need especially careful monitoring.
• Target specific symptoms: Medication should be prescribed for specific, measurable targets -- not vaguely for "autism." What is the specific symptom? How will we measure improvement?
• Consider sensory issues: Autistic individuals may have strong preferences about medication form (tablet vs. liquid vs. capsule), which should be accommodated.
• Avoid polypharmacy: The temptation to add medications for each symptom can lead to complex regimens with cumulative side effects. Each medication should have a clear indication and demonstrated benefit.

My Training in Autism: Learning from a Pioneer

My training in autism comes from one of the world's leading experts. During my child and adolescent psychiatry fellowship at Columbia University, I trained under Jeremy Veenstra-VanderWeele, the Ruane Professor of Psychiatry and director of the Division of Child and Adolescent Psychiatry. Dr. Veenstra-VanderWeele serves on the scientific advisory board of the Simons Foundation Autism Research Initiative (SFARI), the largest private funder of autism research, and his translational research program has advanced our understanding of autism neurobiology, particularly regarding the serotonin and glutamate systems.

This training provided me with a deep understanding of autism neuroscience, evidence-based approaches to diagnosis and treatment, the complexities of managing psychiatric comorbidities in autistic individuals, and the importance of respecting neurodiversity while addressing treatable sources of distress. For more about my research collaborations, see my collaborators page.

Behavioral and Support Interventions

While medication addresses specific symptoms, behavioral and support interventions address broader functioning and quality of life.

Applied Behavior Analysis (ABA): The most widely used behavioral intervention for autism in children. ABA uses reinforcement-based techniques to teach skills and reduce challenging behaviors. It is evidence-based but also controversial within the autistic community, with some individuals reporting that intensive ABA was experienced as coercive or focused on making them "appear normal" rather than supporting their wellbeing. Naturalistic, developmental approaches (Naturalistic Developmental Behavioral Interventions, or NDBIs) represent a more balanced approach.

Speech and Language Therapy: Important for individuals with pragmatic language difficulties (understanding context, metaphor, sarcasm, implied meaning) even when structural language (vocabulary, grammar) is intact.

Occupational Therapy: Addresses sensory processing differences, motor coordination, daily living skills, and environmental modifications. Sensory integration therapy can help individuals manage hyper- or hypo-sensitivity to sensory input.

Social Skills Groups: Structured groups that explicitly teach social skills that neurotypical individuals learn implicitly. Most effective when they teach practical skills rather than requiring autistic individuals to suppress their natural communication style.

Cognitive Behavioral Therapy (adapted): Standard CBT can be modified for autistic individuals by making abstract concepts more concrete and visual, providing written materials and worksheets, allowing more structured session formats, incorporating special interests into therapeutic material, and extending treatment duration.

Workplace Accommodations

Autistic adults are significantly underemployed relative to their capabilities. Workplace accommodations under the Americans with Disabilities Act (ADA) can make a substantial difference.

Common helpful accommodations:

• Written (rather than verbal) instructions and expectations
• Quiet workspace or noise-canceling headphones
• Flexible scheduling or remote work options
• Reduced fluorescent lighting or permission to modify lighting
• Clear, direct communication from supervisors (explicit rather than implied expectations)
• Advance notice of changes to routine or schedule
• Regular structured check-ins rather than informal "how's it going" conversations
• Permission to take sensory breaks
• Exemption from mandatory social events when they cause significant distress

A psychiatric evaluation documenting an ASD diagnosis and specific functional limitations can support accommodation requests. I regularly provide this documentation for my patients and help them identify which accommodations would be most beneficial for their specific needs.

Late Diagnosis: What Now?

For adults receiving an autism diagnosis later in life, the experience can be both validating and disorienting. Many describe a profound sense of relief -- finally understanding why they have always felt different. Others experience grief for the years of struggling without support, or confusion about their identity.

My approach with newly diagnosed adults focuses on psychoeducation (understanding what autism means for them specifically), identifying and treating co-occurring conditions (which have often been misdiagnosed or undertreated), developing strategies to reduce masking burden where safe and appropriate, building self-understanding and self-acceptance, connecting with autistic community resources, and addressing workplace and relationship challenges with new awareness.

Further Reading

• ADHD vs. Autism: How to Tell the Difference
• OCD Treatment NYC
• Child Psychiatrist NYC
• Research Collaborators
• Anxiety Treatment NYC