People experiencing substance use, homelessness, mental ill-health, offending, or repeated crisis involvement are often described as having complex needs. In reality, these needs are not inherently complex they are interconnected. They reflect overlapping experiences of trauma, exclusion, poverty, and systems that have struggled to respond in flexible, humane ways.
This page explores what complex needs really mean, why substance use so often sits at the centre of them, how harm reduction aligns with trauma-informed practice, and what effective, compassionate responses look like in real-world services.
What Are Complex Needs?
The term complex needs is used to describe situations where an individual experiences multiple, overlapping challenges that cannot be addressed in isolation.
These may include:
- Substance use
- Trauma and adverse childhood experiences
- Mental health difficulties
- Homelessness or housing insecurity
- Domestic abuse
- Involvement with the criminal justice system
- Physical health conditions
- Social isolation and poverty
Complex needs are not simply about having more than one issue. They arise when needs interact in ways that intensify risk, increase exclusion, and make standard service pathways ineffective.
Crucially, complex needs are often the result of structural and relational factors, not individual failure. Many people with complex needs have spent years navigating systems that were fragmented, conditional, or punitive.
Related reading:
What Are Complex Needs? Understanding Overlapping Trauma, Substance Use and Mental Health
Why Substance Use Is Central to Complex Needs
Substance use is rarely an isolated issue. For many people experiencing complex needs, drugs or alcohol function as coping mechanisms, survival strategies, or ways of managing overwhelming emotional and physical distress.
Substance use may help someone:
- numb emotional pain or intrusive memories
- manage anxiety, fear, or hypervigilance
- sleep when they feel unsafe
- feel some sense of control or relief
- cope with loneliness, shame, or exclusion
In this context, substance use often makes sense — even when it causes harm. Attempts to address substance use without recognising its function can feel invalidating, unsafe, or punitive, increasing disengagement rather than recovery.
Related reading:
Trauma and Substance Use: Understanding the Link and Building Better Support
Trauma, Harm and Survival Strategies
Many behaviours associated with complex needs are better understood as trauma responses rather than conscious choices.
Trauma particularly when experienced repeatedly or in childhood can shape how people relate to safety, authority, risk, and relationships. Behaviours such as substance use, avoidance, aggression, or withdrawal often reflect attempts to survive environments that once felt threatening or unpredictable.
From a trauma-informed perspective:
- risk behaviours may be protective responses
- “non-engagement” may be avoidance of harm
- relapse may signal distress, not failure
- resistance may reflect fear or loss of trust
Understanding this distinction helps services move away from blame and towards meaningful support.
Related reading:
The Difference Between Resilience and Survival: A Trauma-Informed Perspective
Harm Reduction: A Trauma-Informed Perspective
Harm reduction is often misunderstood. It does not mean ignoring risk, encouraging substance use, or abandoning recovery goals. Instead, harm reduction focuses on reducing immediate harm, increasing safety, and maintaining engagement especially where abstinence is not currently realistic or safe.
From a trauma-informed perspective, harm reduction aligns closely with core principles such as:
- safety
- choice
- dignity
- trust
- collaboration
Examples of trauma-informed harm reduction include:
- meeting people where they are, without judgement
- prioritising safety over compliance
- recognising that change is non-linear
- avoiding punitive responses to relapse
- maintaining consistent relationships even during crisis
For people with complex needs, harm reduction can be the foundation that makes longer-term recovery possible.
Related reading:
Harm Reduction vs Abstinence: A Trauma-Informed Perspective
Complex Needs and Service Exclusion
People with complex needs are disproportionately excluded from services. They may be labelled as:
- “too complex”
- “high risk”
- “non-compliant”
- “not ready”
- “frequent attenders”
This exclusion often occurs because services are designed around:
- single issues
- time-limited interventions
- rigid thresholds
- behavioural conditions
When people are excluded, risk does not disappear it escalates. Exclusion increases the likelihood of:
- rough sleeping
- emergency healthcare use
- safeguarding concerns
- criminal justice involvement
- preventable harm or death
Trauma-informed systems recognise that engagement is itself an outcome, not a prerequisite.
Trauma-Informed Responses to Complex Needs
Responding effectively to complex needs requires more than policies or procedures. It requires a relational, reflective approach across services.
Key principles include:
Psychological and Physical Safety
Creating environments where people feel emotionally and physically safe including how spaces, rules, and interactions are experienced.
Consistency and Predictability
Reliable relationships and clear expectations help rebuild trust, particularly for people who have experienced abandonment or instability.
Relationship-Based Practice
Change happens through relationships. Workers are often the most important protective factor in someone’s life.
Managing Risk Without Punishment
Risk must be taken seriously, but not managed through exclusion, threats, or withdrawal of support.
Multi-Agency Collaboration
Complex needs rarely fit into one service. Joined-up responses reduce gaps and duplication.
Supporting People with Multiple Disadvantage
People experiencing complex needs often face multiple disadvantage overlapping systems of exclusion that reinforce one another.
This may include:
- substance use and homelessness
- trauma and mental ill-health
- safeguarding and criminal justice involvement
- poverty and poor physical health
Effective support recognises that progress in one area may depend on stability in another. For example:
- housing stability may be necessary before addressing substance use
- trauma support may be needed before engagement improves
- safety planning may be more important than abstinence in the short term
Trauma-informed approaches help services respond flexibly without losing accountability or purpose.
Training and Workforce Support
Working with complex needs is emotionally demanding. Without the right support, staff may experience:
- burnout and compassion fatigue
- moral distress
- fear of making mistakes
- pressure to manage risk without adequate tools
Trauma-informed training helps staff:
- understand the impact of trauma on behaviour
- respond with empathy and clear boundaries
- reduce conflict and escalation
- protect their own wellbeing
- work more confidently with risk and uncertainty
Training also supports organisations to shift from reactive, crisis-driven cultures to reflective, relational practice.
Reflect Training: Building Trauma-Informed Practice for Complex Needs
At Reflect Training, we work with frontline teams across health, housing, social care, safeguarding, and substance use services.
Our trauma-informed training supports organisations to:
- improve engagement with people experiencing complex needs
- reduce exclusion and escalation
- strengthen staff confidence and retention
- deliver safer, more compassionate services
Our courses draw on lived experience, real-world case studies, and evidence-based practice supporting teams to apply trauma-informed principles in challenging, high-risk environments.
Final Thoughts
Substance use, harm, and complex needs cannot be understood or addressed in isolation. When services recognise the role of trauma and prioritise safety, dignity, and relationship, people are more likely to engage, stabilise, and recover.
Trauma-informed practice does not lower standards it raises them, ensuring that support is both effective and humane.
Frequently Asked Questions
What are complex needs?
Complex needs refer to situations where a person experiences multiple, overlapping challenges such as substance use, trauma, mental ill-health, homelessness, or criminal justice involvement, which interact and intensify risk.
Why is substance use so common in complex needs?
Substance use often functions as a coping or survival strategy in response to trauma, distress, and exclusion. Addressing it in isolation rarely leads to sustainable change.
What is trauma-informed harm reduction?
Trauma-informed harm reduction focuses on safety, dignity, and engagement. It reduces immediate harm while recognising the role trauma plays in behaviour.
Why are people with complex needs often excluded from services?
Services are often designed around single issues and strict thresholds. People with complex needs may struggle to meet these criteria, leading to exclusion and increased risk.
How can services better support people with complex needs?
Effective support involves trauma-informed practice, flexible pathways, relationship-based work, and multi-agency collaboration.