What’s the Difference Between Bipolar I and II Disorders?

Bipolar disorder is a mental health condition that impacts about 2% of the global population. It causes changes in your mood, called “mood episodes.”

Bipolar disorder exists on a spectrum, and not everyone experiences it the same way.

There are four types of bipolar disorder:

• bipolar I disorder
• bipolar II disorder
• cyclothymic disorder
• bipolar disorder unspecified

If you live with this condition, you may cycle between moods over a period of days, weeks, or months, according to the American Psychiatric Association (APA).

Symptoms of bipolar disorder vary. They may present as mania (or hypomania), depressive episodes, or a combination of both. You may also have periods where you don’t experience extreme highs or lows.

Mania, or a manic episode, is the main diagnostic criteria for bipolar I disorder.

You may have a manic episode for a week or more, during which you’ll feel unusually high in energy or self-confidence, according to the National Institute of Mental Health (NIMH).

During a manic episode, you may talk quickly and jump from topic to topic. You may have difficulty controlling impulses, leading to behaviors like spending more money than usual or driving at high speed.

Sometimes, people with manic episodes also experience symptoms of psychosis. These symptoms often require urgent medical care and can include:

• hallucinations
• delusions
• disorganized thinking and speech

Psychosis can also occur during depressive episodes, but it’s more common during mania.

Hypomania is one of the diagnostic criteria of bipolar II disorder.

A hypomanic episode is similar to a manic episode but considered milder. While many of the symptoms overlap, they differ in the level of intensity.

During a hypomanic episode, you may feel a sense of euphoria or a general “good mood.” It could arrive as a sudden onset of new ideas or creativity. Perhaps you sleep less or have a hard time turning off your brain from racing thoughts.

You may feel more social than usual or have an increased desire for sex. You may also find that you have more energy to do things that you normally feel too tired to do.

This sudden boost in energy levels is not as extreme as during episodes of mania.

A depressive episode may occur in all types of bipolar disorder. Though, contrary to popular belief, it is not required for a diagnosis of bipolar I disorder.

Some signs of a depressive episode include:

• an overwhelming sense of sadness or despair
• appetite or weight changes
• extreme fatigue or exhaustion
• inability to enjoy your favorite activities
• insomnia or trouble falling asleep
• irritability or angry outbursts
• sensory sensitivities (noise, touch, etc.)
• thoughts of self-harm or suicide

While they’re considered separate diagnoses, there are many overlaps between bipolar I and bipolar II disorders.

Onset

For the majority of people, symptoms of bipolar disorder first emerge between the ages of 15 and 24, regardless of the subtype.

In the United States, research shows that 66% of those with a bipolar disorder diagnosis received it before the age of 19. In Europe, it’s about 33%.

Causes

Researchers still don’t know exactly what causes bipolar disorder, but genetics, neurotransmitters, and hormones are thought to play a role.

In both bipolar I and bipolar II, symptoms may be exacerbated by substance use, history of childhood trauma, death of a loved one, or persistent significant stress.

Symptoms

In order to receive a diagnosis of any type of bipolar disorder, you must experience intense changes in mood that differ from your usual state.

You must also experience at least one episode of mania or hypomania.

General symptoms of these episodes may include:

• elevated energy level
• feeling restless
• needing less sleep
• increased self-confidence
• being more talkative than normal
• having a rush of new plans and ideas
• working on multiple projects at once
• being easily distracted
• having decreased inhibitions
• increased libido

Prevalence

Research suggests that bipolar I disorder is the more prevalent of the two.

In one study across 11 countries, researchers found that 0.6% of people live with bipolar I disorder, while 0.4% live with bipolar II disorder.

Depression

There is new research to suggest that those who live with bipolar II disorder may have a higher genetic chance of major depressive disorder (MDD) than those with bipolar I disorder.

In bipolar II disorder, depression may occur more frequently. It may even be your dominant experience.

Symptoms

There are some crucial differences in how the two types are diagnosed.

Everyone’s experience with bipolar disorder is unique.

Treatment of bipolar disorder may include a combination of:

• psychotherapy
• medication
• lifestyle changes
• self-care strategies

You may have additional specifiers in your bipolar disorder diagnosis, like rapid cycling or features of psychosis, that can modulate the type of treatment that’s best for you.

Seeking the help of a mental health professional is highly advisable. They will work with you to create a treatment plan that fits your individual needs and experiences.

Medication

In general, treatment for bipolar I disorder may include mood stabilizers, antipsychotics, and sleep aids.

Treatment for bipolar II disorder may include mood stabilizers and antidepressants, as depressive episodes may show up more often.

Psychotherapy

Some form of therapy is recommended for all types of bipolar disorder.

There are five modalities that may be effective for this condition, according to the National Alliance on Mental Illness (NAMI).

These include:

• cognitive behavioral therapy (CBT)
• family-focused therapy (FFP)
• interpersonal and social rhythm therapy (IPSRT)
• dialectical behavioral therapy (DBT)
• group psychoeducation (aka, group therapy)

Inpatient treatment

Those who live with bipolar I disorder may benefit from hospitalization or inpatient treatment, particularly during manic episodes with symptoms of psychosis. However, this is not the rule, and only a health team can recommend what’s best for you at the time you’re presenting symptoms.

If you’ve been living with bipolar disorder for a while, you may have seen your symptoms shift over time. This is natural as you age and try out different treatments.

With that said, researchers don’t yet know if you can experience one type of bipolar disorder first and then another. Some experts assert that it’s possible, though more studies are needed.

In one older study, 42% of those diagnosed with cyclothymia transitioned to bipolar II or bipolar I disorder. Of those with a diagnosis of bipolar II disorder, 17% changed to a diagnosis of bipolar I disorder.

Living with bipolar disorder, no matter which type it is, can be a challenge.

If your mood episodes occur frequently, feel intense, and sometimes require hospital care, it may be bipolar I disorder.

If your mania symptoms feel more mild, and you experience depressive episodes more often, it may be bipolar II disorder.

Only a mental health professional can provide the right diagnosis. In any case, symptoms of bipolar disorder can be managed and recovery is possible.

To explore your options for diagnosis and treatment, consider these resources:

• American Psychiatric Association’s Find a Psychiatrist tool
• American Psychological Association’s Find a Psychologist tool
• Asian Mental Health Collective’s therapist directory
• Association of Black Psychologists’ Find a Psychologist tool
• National Alliance on Mental Illness Helplines and Support Tools
• National Institute of Mental Health’s Helpline Directory
• National Queer and Trans Therapists of Color Network
• Inclusive Therapists