Diagnosing mental illness is an imperfect science. The DSM (Diagnostic and Statistical Manual) describes bipolar, borderline personality disorder (BPD) and post-traumatic stress disorder (PTSD) as distinct problems, but they share a lot of the same symptoms and can be very hard to distinguish. They also can occur together, which makes it even tougher to sort out.
Some common symptoms of these illnesses are trouble sleeping, thoughts of suicide, not being able to maintain relationships, feeling worthless, racing thoughts, inability to focus, low energy, and feeling heightened emotions. Bipolar, BPD and PTSD can all cause these problems, but for different reasons. For example, someone with bipolar may have trouble sleeping because they are in a manic episode, but someone with PTSD may not be able to sleep because of nightmares or flashbacks. Someone with BPD may have frequent mood swings because of their emotional sensitivity, which can be mistaken for bipolar disorder. A person can have racing thoughts because of bipolar disorder, or because they are triggered by the memory of abuse (PTSD), or because they fear being abandoned (BPD).
So why does the DSM distinguish between these problems? Because although they look alike, they are in fact different. They have different etiologies - they are caused by different things - and need to be treated through different approaches.
Bipolar disorder is a disease and genetics play an important role in whether or not you have bipolar disorder. Research shows that brains of people with bipolar disorder look different than brains of people without the disorder. Treating bipolar disorder often includes use of medication in order to prevent manic or depressive episodes. This is important because these episodes can cause damage to the brain. In addition to medication there are a number of other approaches to treating bipolar disorder, including psychotherapy, taking supplements, exercise and light therapy.
Borderline Personality Disorder (BPD)
The causes of BPD aren't completely known, though we do know that approximately 75% of people with BPD have a history of childhood abuse. There may also be a genetic component, but that's not quite clear yet. Once upon a time BPD was considered an intractable diagnosis. Research over the last several decades, mainly by Dr. Marsha Linehan (founder of Dialectical Behavior Therapy or DBT), has shown that BPD is NOT a lifelong sentence but in fact you can get better. DBT has been studied over the last 30 years and has been shown to be incredibly effective at treating BPD. BPD is a learned response, and therefore it can be unlearned and you can "build a life worth living". What's really fantastic about DBT, though, is it can help anyone live better, happier lives. You can "building a life worth LOVING". I teach DBT to other therapists and use it in my own life, but that's a topic for another day.
Post-Traumatic Stress Disorder (PTSD)
PTSD is caused when you experience a traumatic event - either feeling that your life is threatened or that someone else's life is threatened. PTSD is not caused by the event itself, but rather by the perception of the event. Not everyone who experiences a traumatic event will get PTSD. For example, not everyone in 9-11 has PTSD. Traumatic events can include war, natural disaster, car accidents, invasive medical procedures, physical abuse, childhood abuse or neglect, sexual abuse, domestic violence and so on. Note that both BPD and PTSD have a relationship with childhood abuse and neglect. That's one of the reasons it's hard to separate out these two different diagnoses, and why it's not uncommon for someone to have both. PTSD and trauma aren't treated very effectively by medication, although some medications can put a band-aid on the symptoms. The most effective treatment is therapy, and specifically, therapy targeted at trauma (no, not all therapy is the same).
Even though these diagnoses are caused by different things and should be treated differently, I see them as a spectrum of problems. Therapists and psychiatrists are required to come up with a diagnosis after meeting with someone for one time (if they are going to bill insurance), but it's difficult to be sure. Sometimes it takes months of assessment and re-assessment to make sure you understand what's going on and how to treat it. Make sure you're getting the right treatment for the right problem.
Remember that diagnoses are just a tool. They should never be used to label or limit people, but rather to explain and help people understand. Never confuse the person with the diagnosis. Treat the person.
I'd love to hear your thoughts and experiences about this. Please feel free to leave a comment below.