Two people sitting across from each other at a table, in a therapy session; one using a laptop, the other with an open notebook, a glass of water, and a pen on a notepad; floral arrangement in a vase and decorative items in the background.

Adult Autism Diagnostic Assessment

Autism diagnostic assessments aim to build a clear, evidence-based understanding of an adult’s developmental profile, strengths, and needs. Our assessments are delivered with sensitivity and respect, helping individuals make informed decisions and access appropriate support.

A man sitting on a bench, writing in a notebook with a pen, wearing a gray polo shirt and white pants. There is a plant and abstract artwork in the background.

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition affecting social communication, interaction, and behaviour. It is described as a spectrum because the type and intensity of characteristics vary widely between individuals. Autism is a lifelong neurodevelopmental difference.

What is Autism?

An autism assessment may be helpful for adults who:

Find it difficult to make or maintain friendships, or prefer structured or interest-based social interaction
Experience challenges in the workplace, particularly around communication, change, or managing competing demands
Feel overwhelmed by noise, busy environments, sensory input, or social expectations
Communicate differently, such as finding conversations hard to navigate or preferring predictable topics
Appear anxious, burnt out, or exhausted by everyday social or environmental demands

Who Are Assessments For

When an Assessment May Be Helpful

An autism assessment may be helpful when:

An adult feels different from others, or struggles to explain why certain situations feel harder for them
Differences are becoming more noticeable as social, occupational, or environmental demands increase
Challenges are affecting confidence, emotional wellbeing, relationships, or employment
Individuals or professionals are unsure how best to understand or support their needs
There are ongoing questions despite previous support, therapy, or strategies being in place

What the Assessment Involves

Step 01

Initial enquiry and screening begins with an initial enquiry and completion of screening questionnaires to help us understand the presenting concerns and consider whether a full diagnostic assessment is likely to be appropriate.
Step 02

Review and planning involves careful consideration of all available information so that the assessment approach is tailored to the individual, and in some cases guidance or consultation may be recommended instead of a full assessment.
Step 03

Developmental history explores early development and how the individual’s profile has evolved over time, sometimes involving input from a family member, or other informant where available.
Step 04

Direct assessment and clinical observation involves one or more appointments using discussion, structured tasks, and clinical observation, with standardised tools such as the ADOS-2 used where clinically appropriate.
Step 05

Multidisciplinary clinical integration brings together information from across the assessment through an experienced clinical team to develop a clear diagnostic formulation.
Step 06

Written report and feedback involves sharing a comprehensive written report, followed by a feedback appointment to discuss conclusions, answer questions, and consider next steps.

Report Recognition & Professional Standards

Assessments at Seafield Psychology are conducted by HCPC-registered Clinical Psychologists and other appropriately registered professionals, including Registered Nurses and Speech and Language Therapists. All clinicians involved in the assessment process have several years of experience delivering neurodevelopmental assessments within NHS services.

Assessments are overseen by Dr Catriona Amberton, Clinical Director of Seafield Psychology and Team Lead for a commissioned autism diagnostic service in West Essex. This ensures that assessment processes mirror established NHS pathways in structure, governance and clinical standards.

Assessments are aligned with NICE guidance and, where clinically indicated, incorporate gold-standard tools such as the ADOS-2 and ADI-R. Reports are comprehensive and suitable for sharing with schools, GPs, local authorities, employers and other professionals. They can contribute to EHCP processes and requests for reasonable adjustments where appropriate.

For some families, assessment provides a framework for understanding long-standing differences and advocating for appropriate support.

Waiting Times

Appointments are typically available within a few weeks of initial enquiry. Following completion of the assessment process, reports are usually provided within two to three weeks.

NHS waiting times for neurodevelopmental assessments can often extend to many months or longer. A private assessment can offer clarity and support sooner, allowing families to move forward with appropriate understanding and planning.