14 - Psychiatric Disorders

14.1About psychiatric disorders

The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR)*, published by the American Psychiatric Association, contains a standard classification system of psychiatric disorders for health care professionals in the United States and Canada.  It classified psychiatric disorders by diagnostic category, based on five axes. The five axes, a summary of the diagnostic category for each, and some common disorders falling within each axis are provided in the table below.

(*DSM-IV-TR was published in 2000.  Publication of the DSM-V is expected in 2013.)

Psychiatric Disorders:  Axes, Diagnostic Categories and Common Disorders

(DSM-IV-TR, American Psychiatric Association, 2000)

Axis Diagnostic Category Examples
Axis I Clinical disorders, including major mental disorders, as well as developmental and learning disorders
  • Delirium, dementia and other cognitive disorders
  • Substance related disorders
  • Mood disorders (Major Depressive Disorder, Bipolar Disorders, Dysthymia)
  • Anxiety disorders
  • Attention-Deficit/Hyperactivity Disorder
  • Schizophrenia
Axis II Personality disorders, as well as mental retardation
  • Borderline Personality Disorder
  • Schizotypal Personality Disorder
  • Anti-social Personality Disorder
  • Narcissistic Personality Disorder
Axis III Acute medical conditions and physical disorders
  • Diseases of the nervous, circulatory, musculoskeletal, etc. systems
Axis IV Psychosocial and environmental factors contributing to the disorder
  • Relationship, social, educational, occupational, housing or financial problems may precipitate or aggravate a mental disorder
Axis V Global assessment of Functioning
  • A rating scale, from 0 to 100, used to report on impairment due to psychiatric disorder

This chapter is concerned with Axis I and Axis II disorders.  Axis III focuses on general medical conditions.  Those conditions with relevance to driving safety are addressed in other chapters of this document. Axis IV addresses external factors that may impact a driver’s physical or psychological health and are not addressed in this document.  Axis V, the Global Assessment of Functioning, is a 0 to 100 scale used for reporting a clinician’s judgment of an individual’s level of psychological, social and occupational functioning in light of any impairment due to psychiatric disorders. A low score is a red flag for potential impairment of functions necessary for driving.

Delirium, dementia, and other cognitive disorders (Axis I)

The effects of delirium, dementia and other cognitive disorders on driving are covered in Chapter 6, Cognitive Impairment including Dementia.

Substance-use disorders (Axis I)

Substance-use disorders refer to the taking of a drug of abuse (including alcohol). Substances include alcohol, amphetamines, cannabis, cocaine, hallucinogens, sedatives, hypnotics and anxiolytics.  Alcohol and illicit drug use disorders are not considered in this document.  The effects of drugs commonly prescribed for medical conditions are addressed in Chapter 15, Psychotropic Drugs.

Mood disorders - Major Depressive Disorder, Bipolar Disorder, Dysthymia (Axis I)

Major Depressive Disorder (single episode or recurrent), Bipolar Disorders (Manic, Depressed or Mixed types) and Dysthymic Disorder are collectively referred to as mood disorders.

Major Depressive Disorder is characterized by one or more episodes of depressed mood or loss of interest in usual activities, as well as four additional symptoms of depression, with the episodes lasting for two or more weeks.  Additional symptoms of depression include:

  • change in appetite
  • sleep disturbances
  • decreased energy or fatigue
  • sense of worthlessness or guilt, and
  • poor concentration or difficulty making decisions.

Bipolar Disorder is characterized by one or more manic or mixed (manic and depression) episodes, with or without a history of major depression.

Dysthymic Disorder is defined as a chronically depressed mood over a period of at least two years.

Anxiety disorders (Axis I)

There are a number of anxiety disorders classified in the DSM-IV-TR, including:

  • Generalized Anxiety Disorder
  • specific phobias
  • Posttraumatic Stress Disorder
  • Social Phobia
  • Obsessive Compulsive Disorder, and Panic Disorder.

Symptoms include intense and prolonged feelings of fear or distress that occur out of proportion to the actual threat or danger. The feelings of distress also must be sufficient to interfere with normal daily functioning.

Attention-Deficit/Hyperactivity Disorder (Axis I)

Attention-Deficit/Hyperactivity Disorder (ADHD) is characterized by inappropriate degrees of inattention, impulsivity and overactivity that begin in childhood.  ADHD is one of the most common neurobehavioral disorders of childhood and can persist through adolescence and into adulthood.

Although many individuals with ADHD show symptoms of both inattention and hyperactivity-impulsivity, there may be a predominance of either inattention or hyperactivity-impulsivity.  This variability of presentation is reflected in the three major classifications of the disorder:

  • Combined Type (exhibiting both inattention and hyperactivity-impulsivity)
  • Predominately Inattentive Type, and
  • Predominately Hyperactivity-Impulsivity Type.

The symptoms of hyperactivity and impulsivity tend to diminish over time so that many adults will present with primary symptoms of inattention only.

Schizophrenia (Axis I)

The effects of Schizophrenia on the individual can be profound. Common symptoms include delusions and hallucinations, thought disorders, lack of motivation and social withdrawal.  The symptoms of Schizophrenia are generally divided into three broad categories*:

(*Monash Report 213, April 2004, pg. 272-73)

  • Positive or “psychotic” symptoms are characterized by abnormal thoughts or behaviours.  For example, hallucinations are disturbances of perception where individuals hear or see things that are not there.
  • Disorganised symptoms are characterized by poorly organized, illogical or bizarre thought processes.  These disturbances in logical thought processes frequently produce observable patterns of behaviour that are also disorganized and bizarre.
  • Negative symptoms are characterized by the absence of thoughts and behaviours that would otherwise be expected.  This may be manifested as limited ability to think abstractly, express emotion, initiate activities or become motivated.

The onset of Schizophrenia can occur at any age, but most typically appears in early adulthood.

Many individuals with Schizophrenia have recurring acute psychotic attacks (consisting of positive and/or disorganized symptoms) throughout their life, which are typically separated by intervening periods in which they usually experience residual or negative symptoms.  It is now recognized that early intervention (promptly at the time of the first psychotic break) is very important in preventing major cognitive impairment resulting from this condition.

Personality disorders (Axis II)

There are a number of personality disorders identified in the DSM-IV-TR, including:

  • Borderline Personality Disorder
  • Schizotypal Personality Disorder
  • Anti-social Personality Disorder, and
  • Narcissistic Personality Disorder.

Onset typically occurs during adolescence or in early adulthood. The disorder affects thought, emotion, interpersonal relationships and impulse control.  Symptoms include difficulty getting along with people and the presence of consistent behaviours that deviate markedly from societal expectations.  The prognosis depends on whether the person has an awareness and acceptance of the disorder and its manifestations, and is willing to engage in treatment.

Mental retardation (Axis II)

The DSM-IV-TR defines mental retardation as significantly subaverage intellectual functioning (an IQ of 70 or below), with onset before the age of 18 years, and concurrent deficits or impairments in adaptive functioning.  Mental retardation is not considered in this document.

Suicidal ideation

Suicidal ideation is defined as having thoughts of suicide or taking action to end one’s own life, irrespective of whether the thoughts include a plan to commit suicide.  Studies indicate that more than 90% of all suicides are associated with psychiatric disorders.


For individuals with psychiatric disorders, insight is an important factor in their ability to adhere to treatment and respond appropriately to their condition.  In general, drivers with sufficient insight are those who are aware of any cognitive limitations caused by their disorder and who have the judgment and willingness to adapt their driving to these limitations.


Emotional control – the ability to manage frustration, agitation, impulsivity – is an important functional component of safe driving performance. Affect includes:

  • emotional intelligence
  • impulse control/emotional control
  • frustration threshold
  • agitation, and
  • impulsivity and/or mood control/management.

In this document, affect will be considered as one of the functional abilities needed for driving for drivers with psychiatric disorders.


Psychomotor functions affect the coordination of cognitive processes and motor activity. In this document, psychomotor function will be considered as one of the functional abilities needed for driving for drivers with psychiatric disorders.


Mood disorders - Major Depressive Disorder, Bipolar Disorder, Dysthymic Disorder (Axis I)

In Canada, approximately 8% of adults will experience major depression at some time in their lives, with approximately 1% experiencing Bipolar Disorder. Depression is more common among women, with a female to male ratio of 2 to1.  Women also are 2 to 3 times more likely to develop Dysthymic Disorder.  For Bipolar Disorder, the ratio between males and females is approximately equal.

Anxiety disorders (Axis I)

Anxiety disorders affect 12% of the Canadian population, and result in mild to severe impairment.  The prevalence in the Canadian population is higher for Specific Phobia (6.2%-8.0%) and Social Phobia (6.7%) compared to Obsessive Compulsive Disorder (1.8%), Generalized Anxiety Disorder (1.1%) and Panic Disorder (0.7%).  The prevalence of Posttraumatic Stress Disorder in the United States is estimated to be 8% to 9%.

Attention-Deficit/Hyperactivity Disorder (Axis I)

Prevalence rates of ADHD vary, depending on the diagnostic criteria used, the setting (e.g. general population vs. clinic sample) and the reporter (e.g. parent, teacher, self). Estimates suggest that ADHD affects 3% to 10% of school age children and is 2 to 3 times more common in boys.  It is estimated that 33% to 67% of those with ADHD continue to manifest symptoms into adulthood, and that 5% to 7% of the adult population has ADHD.

Schizophrenia (Axis I)

Schizophrenia affects 1% of the population, with onset typically in early adulthood (late teens to mid-30s).  Males and females are affected equally.

Personality disorders (Axis II)

In the United States, the prevalence of personality disorders is estimated to be between 6% and 9%.

Suicidal ideation

In the general population of Canada, the estimated prevalence of suicidal ideation is from 5% to 18%. The incidence of suicide attempts in the general population is from 1% to 5%.

14.3Psychiatric disorders and adverse driving outcomes

Despite the prevalence of psychiatric disorders in the general population, there have been few investigations into the relationship between these disorders and adverse driving outcomes.  Surprisingly, the majority of research was done, on average, more than 30 years ago.

There are a number of methodological issues that impact the ability to draw conclusions from the existing research, in particular, the impact of improved treatment of psychiatric disorders and changes in the complexity of the driving environment on the results of older studies.  Nonetheless, the consistency of findings supports a general conclusion that drivers with psychiatric conditions are at increased risk of adverse driving outcomes.

Mood disorders - Major Depressive Disorder, Bipolar Disorder, Dysthymic Disorder

A few studies have identified depression as one of a number of factors that may influence driving performance.  However, the results of these studies are equivocal, and methodological limitations significantly limit any conclusions that may be drawn.

Pharmacological treatment of mood disorders is an important consideration.  When treatment is effective, the alertness, cognitive ability and judgment of a person with a mood disorder may be improved.  At the same time, the significant side effects of anti- depressant medications may include impairments in psychomotor functioning, sedation and impairments in cognitive functioning.  The impact of the side effects of drug treatment on driving is considered in Chapter 15, Psychotropic Drugs.

Anxiety disorders

There are no studies that have investigated the relationship between anxiety disorders and driving.  Pharmacological treatment with sedatives or hypnotics may include side effects that impair functional ability to drive. See Chapter 15, Psychotropic Drugs, for more information.

Attention-Deficit/Hyperactivity Disorder

There is a small body of research that suggests that drivers with ADHD are at a higher risk for crashes, have higher rates of traffic citations and licence revocations or suspensions, and are more likely to drive without a licence.

There is some indication that pharmacological treatment of ADHD with stimulants may have a positive effect on driving performance. However, research in this area has primarily relied on driving simulators to measure outcomes.  A few studies have investigated the relationship between pharmacological treatment of ADHD and on-road performance. However, methodological limitations, including small sample size (< 20 in all cases), limit the findings.  The effects of pharmacological treatment of ADHD are discussed further in Chapter 15, Psychotropic Drugs.


The results of the few studies on the relationship between Schizophrenia and adverse driving outcomes are equivocal.  Given the functional impairments often associated with this disorder, the results are surprising.  An important factor which may contribute to the equivocal results is driver licensing rates.  A recent study found that only 52% of individuals with Schizophrenia were licensed to drive compared to 96% in the control group.  Failure to control for the reduced driving exposure of individuals with Schizophrenia is an important consideration in that crash rates are likely an underestimation of impairments in driving performance in this population.

Personality disorders

Two studies, both more than 30 years old, considered the relationship between personality disorders and adverse driving outcomes. Both studies found an increased crash risk for drivers with personality disorders.

Suicidal ideation

Studies on the incidence of traffic suicides indicate that suicide attempts play a significant role in motor vehicle crashes.  Moreover, it is likely that the reported incidence rates of traffic suicides are an underestimation, due to the methodological difficulties in classifying a traffic death as suicide.

Research indicates the following risk factors for traffic suicides:

  • males are significantly more at risk (90% to 95%) than females
  • whites are more at risk than other racial groups
  • those who are “depressed” or “mentally disturbed” are more at risk than those who are not, and
  • those with a history of attempted suicide or a family history of suicide are more at risk than those without such history.

14.4 Effect on functional ability to drive

Condition Type of driving impairment and assessment approach Primary functional ability affected Assessment tools

Mood disorders

Anxiety disorders



Persistent impairment: Functional assessment



Medical assessments

Functional assessments

Episodic impairment: Medical assessment - likelihood of impairment



Medical assessments
Personality disorders Persistent impairment: Functional assessment Affective Medical assessments
Episodic impairment: Medical assessment - likelihood of impairment Affective Medical assessments

Psychiatric disorders can result in either a persistent or episodic impairment of the functions necessary for driving.

The role of insight

A driver’s level of insight is a critical consideration when assessing the risk of an episodic impairment of functional ability due to a psychiatric disorder.

Drivers with good insight are more likely to be diligent about their treatment regime and to seek medical attention and avoid driving when experiencing acute episodes. Poor insight may be evidenced by non-compliance with treatment, trivializing the driver’s role in a crash or repeated involuntary admissions to hospital, often as a result of discontinuing prescribed medication.

Mood disorders - Major Depressive Disorder, Bipolar Disorder, Dysthymia (Axis I)

Cognitive abilities that may be affected by mood disorders include:

  • attention and concentration
  • memory
  • information processing
  • reaction time, and
  • psychomotor functioning.

Anxiety disorders (Axis I)

The research on the effects of anxiety disorders on functional ability is limited.  Findings from studies examining the effects of anxiety disorders on cognitive functioning are equivocal.  Neurobiological studies suggest that medial and temporal lobe structures are affected in anxiety disorders.  These are structures that are responsible for memory and higher order executive functioning.  From a clinical perspective, the potential for diminished attention or perseverating on errors (including “freezing”) in the face of unexpected risks on the road may be of concern for driving.

Attention-Deficit/Hyperactivity Disorder (Axis I)

The pattern of deficits in adults with ADHD is similar to that in children and adolescents. One of the primary cognitive functions that may be affected is the ability to sustain attention, particularly when performing demanding cognitive tasks.  In addition to attentional impairments, individuals with ADHD often experience other cognitive deficits such as difficulties with:

  • planning and forethought
  • flexibility
  • problem solving
  • working memory, and
  • response inhibition.

Symptoms of ADHD referenced in the DSM-IV-TR that may be relevant to driving include:


  • often fails to give close attention to details or makes careless mistakes in school work, work or other activities
  • often has difficulty sustaining attention in tasks or play activities
  • often is easily distracted by extraneous stimuli


  • often is “on the go” or acts as if “driven by a motor”
  • often has difficulty awaiting his or her turn

Schizophrenia (Axis I)

Neuropsychological deficits associated with Schizophrenia may impact driving.  The degree of functional impairment associated with Schizophrenia varies between the acute and residual phases of the disorder.  Neuropsychological functions that may be impaired include:

  • attention
  • executive function
  • spatial abilities
  • memory, and
  • motor and tactile dexterity.

Personality disorders (Axis II)

The characteristics of personality disorders most likely to affect driving include:

  • affectivity (e.g. aggression, frustration, anger)
  • interpersonal functioning (e.g. failure to conform to social norms, reckless disregard for the safety of others), and
  • poor impulse control.

Suicidal ideation

Suicidal ideation is an important consideration regarding drivers with psychiatric disorders because of the risk of traffic suicide.

Pharmacological treatment

In addition to the direct effects of psychiatric disorders on functional ability to drive, the impact of pharmacological treatment is an important consideration when assessing drivers.  The effects of drug treatment are considered in Chapter 15, Psychotropic Drugs.


Drivers with psychiatric disorders are not able to compensate for their impairments.

14.6Guidelines for assessment

14.6.1 Psychiatric disorder - All drivers

National Standard

Note: Requires ballot as 6 months is dropped

All drivers eligible for a licence if

  • the condition is stable
  • the driver has sufficient insight to stop driving if condition becomes acute
  • the functional abilities necessary for driving are not impaired
  • a treating physician supports a return to driving, for drivers who have stopped driving due to a psychiatric disorder, and
  • the conditions for maintaining a licence are met
BC Guidelines
  • If further information regarding an individual’s medical condition is required, RoadSafetyBC may request
    • a Driver’s Medical Examination Report
    • additional information from the treating physician
    • additional information from the individual’s mental health team, or an assessment from a psychologist or psychiatrist
  • If the treating physician indicates that the individual may have persistent functional impairment as a result of the condition or its treatment, RoadSafetyBC may request functional assessment(s) as appropriate for the type of impairment(s) and class of licence held
Conditions for maintaining licence

RoadSafetyBC will impose the following conditions on an individual who is found fit to drive

  • you must stop driving and report to RoadSafetyBC if you are hospitalized due to a mental health issue or if you have a relapse or deterioration of your mental health condition; and
  • you must remain under regular medical supervision and follow your physician’s advice regarding treatment
  • For individuals who have had a psychotic episode, RoadSafetyBC will re- assess annually until the treating physician indicates there have been no further psychotic episodes
  • Otherwise, RoadSafetyBC will determine the appropriate re-assessment interval for individuals with a psychiatric disorder on an individual basis
Information from health care providers
  • Opinion of treating physician whether the condition is stable and controlled
  • Opinion of treating physician whether the driver has sufficient insight to stop driving if condition becomes acute
  • Opinion of treating physician whether the functional abilities necessary for driving may be persistently impaired by the condition or its treatment, and if yes, the results of a functional assessment
  • Whether the driver remains under regular medical supervision
  • Details of any prescribed psychotropic medication regime or other recommended treatment and opinion of treating physician whether the driver is compliant with the treatment
  • A specialist’s report supporting a return to driving, for drivers who have stopped driving due to a psychotic episode
  • Date of most recent psychotic episode
  • Opinion of treating physician as to the appropriate reassessment interval
Rationale Given the nature of psychiatric disorders, assessment must rely primarily on the clinical judgment of health care professionals involved in treatment.  Where the disorder results in a persistent impairment, the impact of that impairment should be functionally assessed