Are women especially vulnerable to depression?

Yes, but...: Statistically, women are twice as likely to be diagnosed with depression. Men are 2-3 times more likely to become alcoholics. Bipolar disorder, which is part of the depression spectrum effects men and women equally. Imo, men are equally likely to have depression, but tend to get diagnosed less frequently than women and use alcohol instead.

Yes : In some population studies, women outnumber men by 2:1 with depression. Other series have the gap smaller, but women still outnumber men. Women are susceptible to a wider array of potential depressogenic events than men: such as pms, pmdd, postpartum depression. If you count these conditions the ratio is close to 2:1 females to males. See http://www.Mayoclinic.Com/health/depression/mh00035.