Complex post-traumatic stress disorder (Complex PTSD or CPTSD) is one of the most pervasive and most functionally disabling conditions in the psychosocial disability population. It arises from prolonged, repeated exposure to traumatic events — most commonly childhood abuse, neglect, domestic violence, out-of-home care, trafficking or exposure to war and political violence — and produces a pattern of functional impairment that goes substantially beyond the intrusive symptoms and hyperarousal of standard PTSD. For many people with complex PTSD, the functional consequences of the condition affect every domain of daily life: their capacity to regulate emotions, form and maintain relationships, trust service providers, maintain housing, engage with employment and manage the ordinary demands of daily living.

Complex PTSD is clinically significant, well-evidenced and can meet the NDIS substantially reduced functional capacity threshold where the presentation is severe, chronic and produces lasting functional limitation. This article explains what complex PTSD is, how it differs from standard PTSD, what its functional consequences are and what a Functional Capacity Assessment must document to support NDIS access and planning.

What is Complex PTSD?

Complex PTSD is a formal diagnosis in the International Classification of Diseases, 11th revision (ICD-11), listed under code 6B41. It is important to understand that Complex PTSD is not a separate diagnosis in DSM-5. Under DSM-5, a person with the same clinical presentation would typically receive a diagnosis of PTSD together with other comorbid diagnoses such as borderline personality disorder, major depressive disorder or dissociative disorder. In clinical practice and in NDIS documentation in Australia, both ICD-11 and DSM-5 are used, and the term Complex PTSD may appear in diagnostic correspondence from psychiatrists and psychologists trained in either system.

Under ICD-11, Complex PTSD has two components. The first is the presence of all three core PTSD symptom clusters: re-experiencing, avoidance and a persistent sense of current threat (hyperarousal). The second is the presence of what ICD-11 calls Disturbances of Self-Organisation (DSO): severe and persistent problems with emotional regulation, negative self-concept and interpersonal difficulties. The DSO symptoms are what distinguish Complex PTSD from standard PTSD and what account for much of its functional severity.

How Complex PTSD differs from standard PTSD

Common sources of complex trauma

Complex PTSD typically arises from prolonged or repeated traumatic experiences, particularly those occurring in childhood or in situations of captivity, entrapment or dependency. Understanding the source of the trauma is clinically relevant because it shapes the specific features of the presentation and its functional consequences. Common sources include the following.

• Childhood physical, sexual or emotional abuse by a caregiver or other trusted adult
• Childhood neglect, including severe emotional neglect and failure of care
• Childhood exposure to domestic violence in the home
• Involvement with the child protection system and out-of-home care, including foster care and residential care placements
• Domestic violence and coercive control as an adult
• Trafficking, forced labour or sexual exploitation
• Torture or prolonged political detention
• War and refugee experiences including ongoing displacement and loss
• Prolonged institutional abuse

The source of the trauma is relevant to the Functional Capacity Assessment because it helps explain the specific triggers, the nature of the interpersonal difficulties and the particular service or system experiences that are most likely to re-traumatise the person during the assessment process itself.

How Complex PTSD affects daily functioning

Emotional dysregulation

Emotional dysregulation is the first of the three DSO components and is the most immediately and visibly impairing feature of Complex PTSD in daily life. People with complex PTSD experience emotions with extreme intensity and have significant difficulty modulating emotional responses once triggered. A perceived interpersonal slight, an unexpected change of plan, a sensory trigger connected to the trauma or an interaction with a service that mirrors the dynamics of the original traumatic relationship can all trigger rapid escalation of emotional distress that is experienced as overwhelming and uncontrollable.

The functional consequences are pervasive. Emotional dysregulation affects the capacity to maintain daily routines when distress escalates unpredictably. It affects the ability to sustain employment because workplace relationships and demands frequently trigger emotional responses that the person cannot manage in a professional context. It affects parenting because intense emotional states are transmitted to children and can produce reactive parenting responses that are later experienced with shame. It affects every service relationship including the NDIS planning process itself. The Functional Capacity Assessment must document the specific pattern of emotional dysregulation for this person — what triggers it, how severe it is, how long it lasts and what functional activities it prevents.

Negative self-concept

The second DSO component — persistently negative self-concept — involves deep, enduring beliefs about the self as worthless, permanently damaged, inherently bad, guilty, shameful or fundamentally different from other people. These beliefs are not simply low self-esteem. They are fixed, pervasive convictions that developed as a response to chronic trauma in which the person was repeatedly treated as if they had no worth and no right to protection or care. Negative self-concept profoundly affects the person’s capacity to seek help, accept support, advocate for their own needs and engage with services including the NDIS.

A person with profound negative self-concept may not believe they deserve support, may minimise their own difficulties in assessment situations, may present as more functional than they are, or may sabotage support arrangements that begin to provide genuine help. The Functional Capacity Assessment must be conducted with an awareness that self-report from a person with negative self-concept is likely to understate the severity of the functional impairment.

Interpersonal difficulties

The third DSO component — severe and persistent interpersonal difficulties — arises directly from the relational nature of the trauma. When trauma occurs within relationships of trust and dependency, the neurobiological and psychological consequences include a profound disruption of the capacity to trust others, to maintain stable relationships and to engage in service relationships without hypervigilance and defensive responses.

People with complex PTSD frequently have a history of relationship breakdown, social isolation, difficulty maintaining the therapeutic relationships required for treatment and significant difficulty navigating service systems. Every new service provider — including the NDIS, support coordinators and the OT conducting the Functional Capacity Assessment — must be negotiated through the lens of a relational history in which trusted others caused harm. Building sufficient trust for an honest and accurate assessment may itself require multiple contacts over time.

Re-experiencing and intrusive symptoms

The re-experiencing symptoms of complex PTSD include flashbacks, intrusive memories, nightmares and sensory re-experiencing of traumatic events that can occur without warning during the course of daily life. These intrusive experiences are not voluntary memories — they are involuntary neurological events in which the person partially or fully relives the traumatic experience in the present moment. They disrupt concentration, disrupt daily tasks, disrupt sleep and create a constant baseline of anxiety from their unpredictability.

For daily functioning, intrusive symptoms affect the capacity to sustain attention on work or household tasks, to drive safely, to be present in the parenting role and to manage any activity that occurs in an environment containing trauma-associated triggers. The Functional Capacity Assessment must specifically document the frequency, intensity and functional disruption caused by intrusive symptoms for this individual.

Avoidance

Avoidance of trauma reminders is a core feature of both PTSD and complex PTSD. In complex PTSD, avoidance is typically more pervasive and more entrenched because the trauma was prolonged and the triggers are more numerous and more deeply embedded in daily life. Avoidance may prevent the person from accessing healthcare, attending government appointments, using public transport where the trauma occurred, visiting specific parts of the community or engaging in intimate or professional relationships.

Avoidance that prevents healthcare access creates secondary functional consequences — physical health conditions go untreated, mental health treatment cannot be accessed, and the person’s overall functional capacity deteriorates further. The Functional Capacity Assessment must document the specific avoidance behaviours present and their functional consequences for this individual.

Hyperarousal and sleep

Chronic hyperarousal — a persistently elevated state of physiological alertness and threat detection — affects the capacity for rest, sleep, concentration and sustained engagement in daily activities. Sleep is almost universally disrupted in complex PTSD, with difficulties falling asleep, staying asleep and experiencing rest due to nightmares. Chronic sleep deprivation compounds every other functional impairment, affecting cognitive functioning, emotional regulation, physical health and the capacity for daily task performance. Hypervigilance in the community means that routine community activities require substantially more cognitive and emotional effort than for a person without this hyperarousal baseline.

Dissociation

Dissociation — a disruption in the normal integration of consciousness, memory, identity or perception — occurs commonly in complex PTSD and can range from brief dissociative episodes involving emotional numbing or feeling detached from the environment through to more prolonged episodes of depersonalisation or derealisation. During dissociative episodes, the person is not fully present in their environment and cannot perform daily tasks safely or effectively. Dissociation may be triggered by trauma reminders or may occur without an identifiable trigger. Where significant dissociation is present, the Functional Capacity Assessment must document its frequency, duration and functional consequences.

The complex social picture: housing, employment and systems

The functional consequences of complex PTSD extend well beyond the immediate symptom presentation and into the social and structural context of the person’s life. Many people with complex PTSD have experienced long-term social consequences of the condition that compound the original trauma.

Housing instability is common, arising from relationship breakdowns, avoidance of specific locations associated with trauma, inability to sustain tenancy agreements due to emotional dysregulation and interpersonal conflict and the downstream consequences of substance use as a coping strategy. Employment instability arises from difficulty managing workplace relationships, hyperarousal in work environments, avoidance of triggers in work settings and the cognitive and emotional consequences of the symptom burden. Engagement with services — including the NDIS, the health system and child protection systems — can itself be re-traumatising where it replicates the power dynamics, unpredictability or lack of control that characterised the original trauma.

Substance use as a mechanism for managing the overwhelming emotional states of complex PTSD is common and must be understood in its functional context rather than as a separate issue. Where substance use is present, the Functional Capacity Assessment must document its functional role, the substances used and the interaction between the substance use and the complex PTSD presentation. The presence of substance use does not disqualify a person from NDIS support.

Complex PTSD and NDIS eligibility

Complex PTSD is not included in NDIS Condition List A or List B by name. NDIS access requires functional evidence demonstrating substantially reduced functional capacity. The primary challenge for NDIS access with complex PTSD is establishing permanence. For some people, complex PTSD responds to evidence-based treatment such as trauma-focused cognitive behavioural therapy or EMDR. For others — particularly those with early onset, prolonged exposure to multiple forms of trauma and significant comorbidities — the functional impairment is longstanding, partially treatment-resistant and likely to be permanent despite optimal care.

The Functional Capacity Assessment must document the treatment history in detail: what treatments have been accessed, for how long, what response was achieved and why the current clinical picture supports the conclusion that the functional impairment is likely to be permanent. Where the treating clinician has provided an opinion on prognosis, this should be documented. Where functional impairment has been present and consistently documented over multiple years despite treatment engagement, this provides a strong evidence base for permanence.

Assessment considerations specific to complex PTSD

Clinical considerations for conducting the FCA with a person with complex PTSD

Trust is not automatic. For many people with complex PTSD, every new professional relationship must be negotiated through a history in which trusted relationships caused harm. The assessment relationship may need to be established across more than one contact before sufficient trust exists for honest and accurate reporting.

Self-report is likely to understate severity. Negative self-concept and shame frequently lead people with complex PTSD to minimise their own difficulties. Assessment of functional capacity must incorporate collateral history and direct observation, not rely primarily on self-report.

The assessment itself may be triggering. Being asked in detail about functional difficulties, history and trauma-related experiences can be triggering for people with complex PTSD. The OT must be attentive to signs of distress or dissociation during the assessment and must be prepared to pause, adjust or reschedule.

Functional capacity fluctuates. Complex PTSD follows an episodic pattern in which functioning is substantially worse during triggered or crisis periods than during stable periods. The assessment must document the full range.

The assessment environment matters. The in-home assessment is particularly important for people with complex PTSD — the person’s own home, on their own terms, provides the greatest possible sense of control and safety.

What a Functional Capacity Assessment covers for complex PTSD

• Documentation of the diagnostic history including the type of trauma, the duration and chronicity of exposure and the current diagnostic formulation
• Assessment of emotional dysregulation and its functional impact on daily activities, employment, parenting, housing and service engagement
• Assessment of interpersonal functioning and the specific ways in which interpersonal difficulty affects the person’s capacity to maintain relationships, access services and engage with the NDIS
• Assessment of intrusive symptoms, avoidance and hyperarousal and their specific functional consequences for this individual in their daily environment
• Assessment of dissociation where present and its frequency, duration and functional implications
• Assessment of sleep disruption and its contribution to overall functional impairment
• Assessment of the housing and employment situation and the role of complex PTSD in any instability
• Assessment of substance use where present and its functional role in the complex PTSD presentation
• Assessment of co-occurring conditions including depression, anxiety, personality disorder features and physical health conditions and their functional contribution
• Documentation of the treatment history and the evidence base for the permanence determination
• Specific recommendations across each NDIS functional domain grounded in direct observation across good and poor-functioning periods

The 2026 NDIS context

The Securing the NDIS for Future Generations Bill 2026, introduced to Parliament on 14 May 2026, strengthens the requirement that NDIS supports must have a direct causal connection to the eligible impairment. For people with complex PTSD, this means the Functional Capacity Assessment must clearly document how the specific features of the complex PTSD presentation — the emotional dysregulation, the interpersonal difficulties, the negative self-concept, the intrusive symptoms and the avoidance — cause the functional impairments documented and justify each support recommendation. A generic psychosocial disability assessment that does not address the specific mechanisms of complex PTSD and their functional consequences will not provide adequate evidence under the current and forthcoming legislative framework.

Who can refer?

Referrals are accepted from participants and families, support coordinators, psychiatrists, psychologists, GPs, community mental health teams, domestic violence services and legal representatives involved in NDIS appeals. Sina OT has completed Functional Capacity Assessments for individuals with psychosocial disability across a range of presentations across Adelaide, Melbourne and Sydney. All assessments are completed in person in the participant’s home and community environment.

Refer to Sina OT

Sina OT is an independent Occupational Therapy practice providing Functional Capacity Assessments across Adelaide, Melbourne and Sydney.

Sina OT has completed Functional Capacity Assessments for individuals with psychosocial disability across a range of presentations including complex trauma. All assessments are completed in person in the participant’s home and community environment by a registered Occupational Therapist.

Services are available in English and Farsi (Persian).