Understanding Mood Disorders: A Comprehensive Guide

(written by Greg Rennie, RP in Toronto Ontario who treats mood disorders and has lived experience)

Mood disorders—including Major Depressive Disorder (MDD), Persistent Depressive Disorder (PDD) also known as Dysthymia, Bipolar Disorder, and Cyclothymic Disorder—represent a significant portion of mental-health concerns in Canada. These conditions impact emotional regulation, cognitive functioning, and daily life engagement.

Major Depressive Disorder (MDD)

Major Depressive Disorder—often referred to as clinical depression—is characterized by a sustained depressed mood or loss of interest or pleasure in activities. Symptoms must be present most days, for a minimum of two consecutive weeks, and cause clinically significant impairment in functioning.

Key Symptoms of Major Depressive Disorder

• Persistent low mood, emptiness, or hopelessness

• Marked loss of interest in previously enjoyed activities

• Significant fatigue or psychomotor changes

• Impaired concentration and decision-making

• Sleep disturbances (insomnia or hypersomnia)

• Appetite or weight fluctuations

• Excessive guilt or feelings of worthlessness

• Recurrent thoughts of death or suicidal ideation

Potential Causes

• Genetic vulnerability

• Stressful or traumatic life events

• Chronic medical conditions or pain

• Hormonal or endocrine changes

• Neurotransmitter dysregulation

• Environmental and lifestyle stressors

Persistent Depressive Disorder (PDD)/Dysthymia

Persistent Depressive Disorder, also known as Dysthymia is classified under depressive disorders in the DSM-5-TR and is defined by a chronically depressed mood lasting at least two years in adults (or one year in children and adolescents).

Because symptoms are long-lasting and often milder than major depressive episodes, PDD can go undetected for years. Many individuals struggle with functioning at work, maintaining motivation, or staying connected socially, yet remain unaware that these experiences are part of a diagnosable condition.

Key Symptoms of Persistent Depressive Disorder

To meet diagnostic criteria, individuals must experience a depressed mood for most of the day, more days than not, along with at least two of the following:

1. Poor Appetite or Overeating

People may experience chronic changes in appetite, often influenced by stress, emotional fatigue, or longstanding mood patterns.

2. Insomnia or Hypersomnia

Sleep difficulties are common and may include trouble falling asleep, staying asleep, or sleeping excessively.

3. Low Energy or Fatigue

A persistent sense of exhaustion can interfere with productivity and daily routines.

4. Low Self-Esteem

Individuals may see themselves as inadequate, incompetent, or unworthy, often internalizing these beliefs as part of their identity.

5. Poor Concentration or Difficulty Making Decisions

Cognitive slowing and reduced mental stamina are frequent features.

6. Feelings of Hopelessness

A pervasive sense that things will not improve is central to dysthymia and differentiates it from temporary mood fluctuations.

Potential Causes

Persistent Depressive Disorder is believed to result from a combination of biological, psychological, and environmental factors.

1. Genetic and Biological Factors

A family history of depression or mood disorders increases vulnerability. Chronic alterations in neurotransmitter systems (serotonin, dopamine, norepinephrine) may also contribute.

2. Early Life Stress or Trauma

Neglect, chronic stress, or adverse childhood experiences can shape long-term emotional patterns and coping mechanisms.

3. Personality Factors

Individuals with high levels of neuroticism, self-criticism, or chronic pessimism are at higher risk.

4. Environmental Stressors

Long-term interpersonal conflict, socioeconomic challenges, or ongoing stress can reinforce depressive patterns.

Diagnosis of Persistent Depressive Disorder

Diagnosis requires a comprehensive clinical assessment, including:

• A detailed psychosocial and medical history

• Symptom evaluation and duration

• Screening for major depressive episodes

• Assessment for co-occurring conditions (anxiety disorders, substance use, ADHD)

• Functional impairment across work, relationships, and daily routines

Because symptoms are chronic and sometimes mild, clinicians often rely on careful interviews and longitudinal assessment to ensure accurate diagnosis.

Evidence-Based Treatment for PDD

Persistent Depressive Disorder is highly treatable, and combining therapy with medication often leads to the best outcomes.

1. Psychotherapy

Several modalities have strong evidence:

• Cognitive Behavioural Therapy (CBT)
  Helps individuals challenge negative thought patterns and develop healthier coping strategies.

• Cognitive Behavioural Analysis System of Psychotherapy (CBASP)
  A specialized treatment designed specifically for chronic depression.

• Interpersonal Therapy (IPT)
  Addresses interpersonal stressors and relationship patterns that contribute to chronic low mood.

• Mindfulness-Based Interventions
  Improve emotional regulation and reduce rumination.

2. Lifestyle Interventions

Although not a replacement for formal treatment, supportive strategies can improve outcomes:

• Regular exercise

• Sleep hygiene

• Structured routines

• Nutrition support

• Stress management techniques

4. Combined Treatment

For many individuals with PDD, combining psychotherapy and pharmacotherapy yields the strongest and most durable improvement.

When to Seek Professional Help

Because PDD is often subtle and long-lasting, many individuals delay seeking help. It is important to reach out if you or someone you know is experiencing:

• A consistently low mood lasting two years or more

• Loss of interest in normal activities

• Difficulty maintaining motivation or relationships

• Chronic fatigue or cognitive difficulties

• Persistent feelings of hopelessness

Early intervention can significantly improve long-term functioning and reduce the risk of developing major depressive episodes.

Bipolar Disorder

Bipolar disorder is a complex, chronic mood disorder characterized by significant shifts in mood, energy, activity level, and functioning. These changes occur in distinct episodes of depression, mania, or hypomania. While many people experience fluctuations in mood, bipolar disorder involves changes that are more intense, longer-lasting, and disruptive to daily life.

As one of the most researched psychiatric conditions, bipolar disorder affects approximately 1–5% of the population worldwide. Early recognition and evidence-based treatment substantially improve long-term outcomes, making accurate information essential.

Core Features of Bipolar Disorder

Bipolar disorder is defined by two primary mood states:

1. Depressive Episodes

These episodes resemble major depressive disorder (severe) and may include:

• Persistently low mood or hopelessness

• Loss of interest or pleasure

• Fatigue or decreased energy

• Sleep disturbances (insomnia or hypersomnia)

• Changes in appetite

• Difficulty concentrating

• Thoughts of worthlessness or suicidal ideation

Depressive episodes can be severe and disabling, often prompting individuals to seek treatment.

2. Manic Episodes

A manic episode is a hallmark feature of bipolar disorder, characterized by a distinct period of abnormally elevated, expansive, or irritable mood that significantly impacts daily functioning. Clinically, a manic episode typically lasts at least one week (or any duration if hospitalization is necessary) and is accompanied by increased energy or activity.

Key Symptoms of Manic Episodes
During a manic episode, individuals may experience a combination of the following symptoms:

• Elevated or irritable mood: Feeling euphoric, unusually optimistic, or excessively irritable.

• Increased energy and activity: Restlessness, hyperactivity, or an urge to engage in multiple projects simultaneously.

• Grandiosity: Inflated self-esteem or unrealistic beliefs in one’s abilities or powers.

• Reduced need for sleep: Feeling rested after only a few hours of sleep.

• Racing thoughts and rapid speech: Difficulty focusing due to fast-moving ideas and pressured speech.

• Impulsivity or risky behaviors: Overspending, reckless driving, hypersexuality, or unwise business decisions.

• Distractibility: Easily drawn to irrelevant external stimuli.

Clinical Significance
Manic episodes can cause severe disruptions in personal, social, and occupational functioning. In some cases, mania may escalate into psychotic features, including delusions or hallucinations, requiring urgent psychiatric intervention. Proper diagnosis and timely treatment are critical to managing symptoms and preventing long-term complications in bipolar disorder.

Treatment Approaches
Management of manic episodes often involves a combination of:

• Mood stabilizers (e.g., lithium, valproate)

• Atypical antipsychotics for acute mania

• Psychotherapy (CBT, psychoeducation) to help patients recognize triggers and manage stress

• Lifestyle interventions including sleep regulation, structured routines, and stress management

3. Hypomanic Episodes

A hypomanic episode is characterized by a distinct period of elevated, expansive, or irritable mood, lasting at least four consecutive days, which represents a clear change from an individual’s baseline functioning. Unlike full manic episodes, hypomania does not cause severe functional impairment or necessitate hospitalization, though it can significantly impact interpersonal relationships, work performance, and decision-making.

Symptoms of Hypomania
During a hypomanic episode, patients may exhibit a combination of the following symptoms:

• Elevated or irritable mood: Unusually cheerful, enthusiastic, or quick to anger.

• Increased energy and activity: Heightened goal-directed activity at work, school, or socially.

• Reduced need for sleep: Feeling rested after only a few hours of sleep.

• Racing thoughts and distractibility: Rapid idea generation and difficulty maintaining focus.

• Increased talkativeness or pressured speech: Speaking more than usual and often more loudly.

• Inflated self-esteem or grandiosity: Overconfidence in abilities, sometimes bordering on risk-taking behavior.

• Engagement in risky behaviors: Impulsive spending, sexual indiscretions, or hasty business decisions.

Clinical Significance
Although hypomanic episodes are less severe than manic episodes, they are critical in the diagnosis of bipolar disorders, particularly Bipolar II Disorder, where major depressive episodes alternate with hypomania rather than full mania. Recognition of hypomania is essential because it often precedes depressive episodes, and early intervention can improve long-term outcomes.

Diagnosis and Treatment
Hypomania is diagnosed through clinical evaluation, patient history, and mood charting. Effective management may include psychotherapy (such as cognitive-behavioral therapy), mood stabilizers (like lithium or lamotrigine), and psychoeducation to help patients recognize early signs of mood elevation. Timely treatment can reduce episode frequency, improve functioning, and prevent progression to more severe mania.

Types of Bipolar Disorder

Accurate diagnosis depends on the pattern, duration, and intensity of mood episodes.

Bipolar I Disorder

• Defined by at least one manic episode, with or without depressive episodes.

• Mania lasts at least seven days or requires hospitalization.

• Depressive episodes are common but not required for diagnosis.

Bipolar II Disorder

• Involves at least one hypomanic episode and one major depressive episode.

• Hypomania does not involve psychosis or require hospitalization.

• Depressive symptoms tend to be more frequent and often more burdensome.

Mixed Features

Some individuals experience mixed episodes, where symptoms of mania and depression occur simultaneously.
Examples include:

• Feeling depressed but restless and agitated

• Having racing thoughts but also feeling hopeless

• Increased energy paired with suicidal ideation

Mixed states increase clinical risk and can complicate treatment, making early recognition crucial.

Rapid Cycling

Rapid cycling is defined as experiencing four or more mood episodes within a 12-month period. These episodes can be manic, hypomanic, depressive, or mixed, and they may occur in succession or alternate. Rapid cycling can affect both Bipolar I and Bipolar II disorder and is often associated with a more severe course of illness.

Symptoms of Rapid Cycling

Unlike standard bipolar disorder, where mood episodes may last months, rapid cycling causes frequent and often unpredictable shifts, leading to significant distress and functional impairment.

Causes and Risk Factors

The exact causes of rapid cycling are not fully understood, but several factors may contribute:

• Genetic predisposition: Family history of bipolar disorder increases risk

• Biological factors: Neurotransmitter imbalances and circadian rhythm disruptions

• Hormonal changes: Particularly in women (e.g., thyroid dysfunction, menstrual cycle variations)

• Medication factors: Certain antidepressants can trigger rapid cycling in some individuals

• Stress and lifestyle factors: Chronic stress, sleep disruption, and substance use

Diagnosis

Diagnosis of rapid cycling requires a comprehensive psychiatric assessment, including:

• Detailed history of mood episodes

• Identification of episode frequency and duration

• Screening for medical conditions that may mimic mood symptoms

• Assessment of medication effects and substance use

Early recognition is critical, as rapid cycling is associated with higher relapse rates and increased risk of comorbid conditions, such as anxiety disorders or substance misuse.

Treatment Options for Rapid Cycling

Managing rapid cycling requires a multifaceted approach:

Psychotherapy

• Cognitive-behavioral therapy (CBT): Helps identify triggers and develop coping strategies

• Interpersonal and social rhythm therapy (IPSRT): Focuses on stabilizing daily routines and sleep patterns

• Psychoeducation: Empowers patients and families to recognize early signs of mood shifts

Lifestyle and Supportive Strategies

• Maintaining a regular sleep schedule

• Stress management through mindfulness, exercise, and relaxation techniques

• Avoiding alcohol or recreational drugs

• Building a strong support network

Prognosis

While rapid cycling can be challenging to treat, early intervention and a combination of medication, psychotherapy, and lifestyle management can significantly reduce episode frequency and severity. Patients who actively engage in treatment often experience improved mood stability and quality of life.

What Causes Bipolar Disorder?

Bipolar disorder arises from a combination of factors:

Biological Factors

• Strong genetic component (first-degree relatives have significantly higher risk)

• Neurotransmitter dysregulation involving dopamine, serotonin, and glutamate

• Differences in brain circuitry related to emotion regulation and energy balance

Psychological and Environmental Factors

• Childhood trauma

• Chronic stress

• Irregular sleep patterns

• Substance use

• Major life events

Most cases result from the interaction between biological vulnerabilities and environmental triggers.

How Bipolar Disorder Is Diagnosed

Diagnosis typically includes:

• Comprehensive psychiatric assessment

• Detailed history of mood episodes

• Collateral information from family (when appropriate)

• Rule-out of medical causes (e.g., thyroid disorders, neurological conditions)

• Screening for substance-induced symptoms

Because symptoms often overlap with depression, ADHD, PTSD, or personality disorders, proper evaluation by a trained clinician is essential.

Evidence-Based Treatments for Bipolar Disorder

Psychotherapy

Effective approaches include:

• Cognitive Behavioural Therapy (CBT)

• Interpersonal and Social Rhythm Therapy (IPSRT)

• Psychoeducation

These therapies support mood regulation, relapse prevention, lifestyle stabilization, and improved insight.

Lifestyle and Support Interventions

• Consistent sleep schedule

• Routine physical activity

• Minimizing substances (alcohol, cannabis, stimulants)

• Stress reduction

• Strong therapeutic alliance and ongoing monitoring

Long-Term Outlook

Bipolar disorder is a lifelong condition, but with proper treatment, most individuals experience significant improvement in stability, functioning, and quality of life. Early intervention, consistent medication adherence, and structured psychosocial support are key protective factors.

Cyclothymic Disorder

Cyclothymic disorder is a chronic mood disorder involving at least two years (one year for children and adolescents) of numerous periods with hypomanic symptoms and numerous periods with depressive symptoms that do not meet the full criteria for a hypomanic episode or a major depressive episode.

People with cyclothymia often describe their mood as “up and down” in ways that feel difficult to explain but impossible to ignore. While symptoms may be less intense than bipolar disorder, the long-term instability can still cause significant emotional, social, and occupational challenges.

How Cyclothymic Disorder Differs From Bipolar Disorder

Cyclothymia sits on the bipolar spectrum but is clinically distinct.

Cyclothymia vs. Bipolar I

• Bipolar I involves full manic episodes, which cyclothymia does not include.

• Cyclothymia involves subthreshold symptoms.

Cyclothymia vs. Bipolar II

• Bipolar II includes clear hypomanic episodes and major depressive episodes.

• Cyclothymia involves constant mood fluctuations but no full episodes of either type.

Cyclothymia vs. “Moodiness”

This disorder is not simply emotional variability—it is a persistent, diagnosable condition with biological, psychological, and social components.

Causes and Risk Factors

While no single cause has been identified, research suggests a combination of:

• Genetic vulnerability: Higher likelihood in individuals with a family history of bipolar disorder or mood disorders.

• Neurobiological factors: Differences in emotional regulation, neurotransmitter functioning, and stress-response systems.

• Environmental triggers: Trauma, chronic stress, inconsistent sleep patterns, and unstable interpersonal environments can intensify cycles.

Cyclothymia often begins in adolescence or early adulthood, though many individuals may not seek treatment until later in life.

Diagnosis of Cyclothymic Disorder

A qualified mental health professional—such as a psychiatrist, psychologist, or psychotherapist—conducts a thorough clinical assessment including:

• Symptom timeline (two years minimum)

• Mood patterns and triggers

• Medical and psychiatric history

• Rule-out of bipolar I/II, major depression, ADHD, borderline personality disorder, and substance-related mood disturbances

Because symptoms can feel subtle or normalized by the individual, diagnosis often requires detailed history-taking and observation.

Treatment Options for Cyclothymic Disorder

While cyclothymia is a long-term condition, evidence-based treatment significantly improves stability, insight, and functioning.

Psychotherapy (First-Line Treatment)

Psychotherapy is a central component of managing cyclothymic disorder. Effective modalities include:

• Cognitive Behavioural Therapy (CBT): Addresses thought patterns and behaviours that contribute to mood swings.

• Dialectical Behaviour Therapy (DBT): Helps with emotional regulation, distress tolerance, and interpersonal stability.

• Interpersonal Therapy (IPT): Supports relationship health and communication.

• Psychoeducation: Teaching patients to identify early mood changes and implement preventative strategies.

Consistent therapy helps individuals recognize patterns, reduce impulsivity, and build healthier daily routines.

Lifestyle Interventions

Long-term mood regulation is improved by:

• Stable sleep routines

• Consistent physical activity

• Stress-reduction practices (mindfulness, yoga, relaxation techniques)

• Limiting substance use

• Balanced nutrition

These habits help regulate the circadian rhythm, which plays a major role in bipolar-spectrum conditions.

Prognosis and Long-Term Outlook

Cyclothymic disorder is highly responsive to treatment when recognized early. Many individuals achieve:

• Greater emotional stability

• Better relationship functioning

• Stronger coping strategies

• Reduced intensity and frequency of mood fluctuations

Because the disorder is chronic, ongoing support and monitoring are often recommended to maintain long-term stability.

When to Seek Professional Help

If you notice persistent mood changes that affect your work, relationships, or sense of control, reaching out to a mental health professional is an important first step. Early treatment can prevent symptoms from intensifying and can reduce the risk of developing bipolar disorder.

Evidence-Based Treatment Options for Mood Disorders in Toronto

Greg Rennie, RP who specializes in treating mood disorders inToronto offers a comprehensive mental-health treatment landscape, including psychotherapy, psychiatry, holistic interventions, and innovative therapies for mood disorders.

Psychotherapy

Clinical, evidence-based therapeutic approaches include:

• Cognitive Behavioral Therapy (CBT)

Targets maladaptive thought patterns and associated behaviors; widely used for depression and anxiety.

• Interpersonal and Social Rhythm Therapy (IPSRT)

A leading intervention for bipolar disorder focusing on stabilizing routines and interpersonal functioning.

• Integrative Supportive Psychotherapy

Greg Rennie in Toronto combines CBT, DBT, ACT, and trauma-informed approaches to meet complex clinical needs.

• Holistic and Lifestyle Interventions

Long-term recovery is strengthened by:

• Sleep hygiene improvements

• Regular exercise

• Balanced nutrition

• Mindfulness or meditation

• Psychoeducational and peer support groups

Emerging and Innovative Treatments

Toronto is at the forefront of novel interventions for treatment-resistant mood disorders and Greg Rennie has been trained in Ketamine-Assisted Therapy (KaT) and supervises the therapeutic process.

Ketamine-Assisted Therapy (KaT)

Provides rapid symptom reduction for treatment-resistant depression and bipolar depression under trained clinical supervision.

Greg Rennie, Psychotherapist Specializing in Mood Disorders

In Toronto, finding a mental health professional who deeply understands mood disorders is invaluable. Greg Rennie, a Registered Psychotherapist (RP) with over 20 years of experience helping individuals and families navigate the challenges of bipolar disorder, depression, trauma, and addiction may be someone to consider.

A Therapist With a Unique Blend of Professional and Lived Insight

Greg isn’t just a clinician — his journey is informed by both his professional training and personal lived experience: he’s worked in mental health and addiction settings for over 20 years, and he also has personal insight into bipolar disorder through family experience.

This dual perspective – clinical and personal – gives his work a richness and empathy that clients often mention in testimonials. He meets people “where they are on the spectrum,” whether they’re already diagnosed or suspect they might have a mood disorder.

Areas of Specialization

Bipolar Disorder & Mood Disorders

Greg’s primary focus is on bipolar disorder — both type I and type II — and mood dysregulation more broadly. He has specialized training in Interpersonal and Social Rhythm Therapy (IPSRT), an evidence-based therapy particularly well-suited for bipolar disorder, since it helps people regulate their daily routines (sleep, activity, social rhythms), which can have a major impact on mood stability. He also supports family members (parents and partners) impacted by bipolar disorder.

Addiction and Co-Occurring Disorders

In addition to mood disorders, Greg has extensive experience in addiction therapy — covering substance use, behavioral addictions, and sex or porn addiction. He’s worked in prominent addiction treatment centers like Homewood Health Centre and Bellwood Health Services.

Importantly, he treats co-occurring conditions — for example, a client with bipolar disorder and substance use may benefit from his integrated understanding of both.

Trauma

Greg also supports clients with trauma, utilizing evidence-based modalities such as Cognitive Processing Therapy (CPT) and Prolonged Exposure (PE), alongside more general trauma-informed approaches.

Innovative Treatment: Ketamine-Assisted Psychotherapy

One of the more cutting-edge aspects of Greg’s practice is his use of Ketamine-Assisted Therapy (KaT) for bipolar depression. He is also trained in Psychedelic-Assisted Therapy, adding to his toolkit for clients who have not responded fully to more traditional treatments.

Therapeutic Approach & Philosophy

Greg’s therapeutic style is characterized by warmth, compassion, and a deeply person-centered approach. He believes in meeting people exactly where they are — not just in terms of symptoms, but in their life context, relationships, and personal goals.

He draws from a variety of therapeutic modalities, including:

• Cognitive Behavioral Therapy (CBT) — to help people identify and reframe harmful thought patterns.

• Dialectical Behavior Therapy (DBT) — which can be useful for emotion regulation.

• Interpersonal and Social Rhythm Therapy (IPSRT), as noted, for rhythm stabilization.

• Motivational Interviewing — especially in addiction work.

• Solution-Focused Brief Therapy (SFBT) — for goal-setting and practical change.

He also provides psychoeducation to clients and families, helping them understand the biological, psychological, and social factors in mood disorders and addiction.

Credentials & Training

• Education: He holds a Bachelor of Social Work from the University of Waterloo, and a diploma in Addiction Carework from McMaster University.

• Professional Registration: He is registered with the College of Registered Psychotherapists of Ontario (CRPO), license number 004569.

• Specialized Training: Certificate in Psychedelic-Assisted Therapy from ATMA CENA.

• Personal Practice: He’s also a longtime meditator (Zen Buddhism) and has experience with non-ordinary states of consciousness (e.g., breathwork), which informs his empathy for clients exploring more novel therapies.

Practice Details

• Location: His clinic is located at 1600 Steeles Avenue W, Unit 316, Vaughan, ON.He sees Toronto clients, both virtually and in person.

• Hours: In-person and virtual sessions are available; his online booking shows times on Wednesdays, Thursdays, and Fridays.

• Insurance: He provides receipts for insurance reimbursement (many major Canadian insurers accepted)

• Intro: He offers a free 15-minute phone consultation to help prospective clients decide if his style is a good fit. To book a consult/resonance check click here.

Clients who work with Greg often report that his approach helps them feel seen — not just as someone with a diagnosis, but as a whole person. By combining structured therapies (like IPSRT) and novel approaches like ketamine-assisted therapy, he helps people build resilience, stability, and self-understanding.